perceptions of usability and design ... - diabetes spectrummost important features to them in...

16 Diabetes Spectrum Volume 26, Number 1, 2013

Abstract

Feature Article / Perceptions of Insulin Pens for Type 2 Diabetes

Address correspondence to Louise Heron, MA, Adelphi Mill, Grimshaw Lane, Bollington, Cheshire, SK10 5JB, U.K.

Perceptions of Usability and Design for Prefilled Insulin Delivery Devices for Patients With Type 2 DiabetesLouise Heron, MA, Matthew Reaney, MSc, Norbert Hermanns, PhD, Linda Abetz, MA, and Laura Gregg, BA

Diabetes has become one of the most common noncommunicable dis-eases globally and has been deemed one of the most challenging health problems of the 21st century.1 In the United Kingdom alone, diabetes affects 4.9% of the population (~ 2.1 million people) and accounts for 5% of the total National Health Service expenditure.1,2 Furthermore, type 2 diabetes represents 90% of all cases of diabetes in the United Kingdom.2 The goal for diabetes management in type 2 diabetes patients is to main-tain normalized blood glucose levels,

reducing the risk of micro- and mac-rovascular complications.

Multiple oral and injectable medication classes exist for type 2 diabetes; each class affects blood glucose control through different mechanisms and has different effects on glucose profiles and on other important clinical outcomes such as weight.3 Insulin is the most effective class of medication in lowering blood glucose,3 although the estimated time frame for onset of insulin use in type 2 diabetes patients is ~ 8–10 years after diagnosis.4

Although many patients with type 2 diabetes are initially managed through lifestyle modification, most eventually require insulin therapy. However, insulin initiation is often delayed because of factors such as patients’ resistance to insulin therapy and worries about injections. Such delays affect glycemic control, have a direct effect on patient encounters, and may affect medication adher-ence. Insulin pen delivery systems may address some of these concerns.

This study had two phases. First, semi-structured qualitative inter-views were conducted to identify the most important features of insulin delivery devices for prandial use from the perspective of patients (n = 8) and health care professionals (HCPs; n = 10). From phase 1, a 26-item questionnaire was developed. In phase 2, patients (n = 33 insulin naive, n = 78 pen users) and HCPs (n = 151) were asked to indicate the most important features to them in insulin delivery devices. Patients then simulated injection using three differ-

ent pens (SoloSTAR, KwikPen, and FlexPen) and ranked them based on the same features.

The most important features were knowing that the entire dose has been injected, ease of reading the dose correctly, and ease of cor-recting if the dose is over-dialed. In the simulation study, KwikPen and SoloSTAR scored significantly higher (paired t test, P < 0.05) than FlexPen on “knowing if you have injected the entire dose” (mean score out of 10: KwikPen, 8.9; SoloSTAR, 8.6; and FlexPen, 8.4). No other significant differences among the pens were noted in usability or design, and the mean ranking (from 1 to 3) of the pens was similar (KwikPen, 2.0; FlexPen, 2.1; and SoloSTAR, 1.9). By identifying which insulin delivery pens offer these features, HCPs can choose the most appropriate delivery device for patients, which may lead to earlier insulin initiation, greater patient adherence, and better clinical outcomes.

17Diabetes Spectrum Volume 26, Number 1, 2013

Feature Article / Heron et al.

For many of these patients, poor glycemic control is evident for a long period of time before initiation of insulin.5 The inappropriate intensifi-cation of treatment to insulin therapy further affects glycemic control, has a direct impact on patient encoun-ters, and may affect adherence to medications.6–10 Earlier use of insulin in patients with type 2 diabetes has therefore been recommended by the European Association for the Study of Diabetes and the American Diabetes Association.3

Delays in initiating insulin therapy may result from patients’ psychological resistance to insulin, clinical inertia, or a combination thereof.11,12 Insulin is commonly initiated as basal therapy and may be intensified by the use of short- or rapid-acting insulin before meals (prandial insulin), or by using biphasic (premixed) insulin for-mulations.3,13,14 In some European countries, prandial insulin is also frequently used within initial insulin regimens.15 Insulin regimens can therefore be complex, requiring patients to administer multiple daily injections and health care provid-ers (HCPs) to provide appropriate training and support.16 Furthermore, patients’ fears regarding insulin treatment often concern handling problems, hypoglycemia,17 and insu-lin self-injection,18–20 as well as the perception that insulin therapy is an indication that self-management (and therefore the patient) has “failed.”21 This highlights the importance of considering patient burden in the management of type 2 diabetes.

In addition to the reluctance to initiate insulin therapy, nonadher-ence to insulin is a significant issue in the management of type 2 diabe-tes,22 with estimates of nonadherence ranging from 7 to 64% depending on the population and therapy stud-ied.23–25 Poor adherence to insulin has been associated with reduced therapeutic effectiveness, poor metabolic outcomes, decreased time to onset and progression of severe microvascular complications, hospi-talizations, emergency department visits, and mortality.4,23,26–30 The additional cost to U.S. health care system of nonadherence to pharma-

cotherapy in type 2 diabetes has been estimated to be as much as $846 per patient per year.31

Insulin pen delivery systems may help to address some patient concerns regarding insulin therapy. Studies have shown more favorable patient-reported outcomes (e.g., acceptability, treatment satisfac-tion, ease of use, convenience, less injection pain, and decreased social stigma) with insulin pen delivery systems than with vial-and-syringe delivery systems.32–35

Since the launch of the first insulin pen delivery system in the mid-1980s (NovoPen, Novo Nordisk), pharmaceutical and device manufacturers have developed sev-eral easy-to-use prefilled disposable pen devices. These disposable pens are common and are generally more convenient for patients than reusable pens.31,36

This study sought first to understand the relevant features of prefilled disposable insulin pens from the perspective of patients and HCPs. It then aimed to elicit patients’ and HCPs’ perceptions of pen usability and design when simulat-

ing a prandial insulin injection using three of the global market–leading prefilled disposable pens: SoloSTAR (Sanofi Aventis, Paris, France), KwikPen (Eli Lilly, Indianapolis, Ind.), and FlexPen (Novo Nordisk, Copenhagen, Denmark).

Study Methods

Study designThe study was conducted in two phases, as illustrated in Figure 1. Patients who were insulin-naive and current or previous prefilled insu-lin pen users were recruited to the study. The HCP sample comprised diabetologists and diabetes nurse educators (DNEs).

For both phases, the inclusion criteria for patients were as follows:• Insulin-naive patients: < 80 years

of age, at least 2 years’ duration of type 2 diabetes, only receiving oral antihyperglycemic agents, not using injectables for any other condition, comfortable and open to discussing insulin injection at interviews, able to complete simu-lated injections without assistance from others.

Figure 1. Study design and quantitative phase process.



• Prefilled pen users: < 80 years of age, at least 2 years’ dura-tion of type 2 diabetes, currently injecting prandial insulin using a prefilled pen delivery system with or without oral antihyperglycemic agents or a basal (long-acting) insulin, not using injectables for any other condition, comfortable and open to discussing insulin injection at interviews, able to complete simulated injections without assistance from others.

To ensure that HCPs could speak about patients’ perceptions with confidence, the inclusion criteria for HCPs were as follows:• Diabetologists: Qualified for

more than 4 years, consultants (specialists) only, workload of > 100 patients per month with at least 60 patients per month consulting on type 2 diabetes, personally makes the decision to initiate insulin therapy and chooses the insulin brand to prescribe, currently prescrib-ing prandial insulin delivered through at least two of the three pen brands of interest (FlexPen, KwikPen, and SoloSTAR).

• DNE: Qualified for more than 4 years, workload of > 20 diabetes patients per month, person-ally trains patients on insulin injections or devices, currently prescribing prandial insulin deliv-ered through at least two of the three pen brands of interest.

Questionnaire development for phase 1 (qualitative phase)The qualitative phase of the study aimed to identify concepts related to insulin pens that were important to measure and therefore to optimize the questionnaire design for the quantitative phase. Patients were recruited in the United Kingdom via fieldwork agencies that used HCPs and patient associations to identify potential patients from their databases. With their permission, patients were screened for eligibility.

The study was completed in accordance with current British Healthcare Business Intelligence Association guidelines.37 Semi-structured interviews were conducted with a small cohort of

patients with type 2 diabetes (n = 4 insulin-naive, n = 4 pen users), DNEs (n = 5), and specialist physicians (n = 5). Patients and HCPs gave written informed consent. After open-ended concept elicitation to understand important features of insulin pens for prandial insulin delivery, an existing questionnaire containing 18 items on the features of insulin pens38 was provided to participants, who were asked about its comprehensiveness and ease of understanding. The interviews were conducted as 30-minute telephone calls with HCPs and 60-minute face-to-face meetings with patients.

The interviews were digitally recorded and analyzed thematically for missing concepts or features, lack of clarity, and redundancy in the questionnaire.39 The question-naire38 was then adapted according to the qualitative results to provide a comprehensive survey of the key fea-tures of prefilled insulin pens. Two versions of this questionnaire were created: one to evaluate the impor-tance of the features and another to evaluate the perception of the insulin pens on these features.

Data collection for phase 2 (quantitative phase) Using the same inclusion criteria, additional patients were recruited through fieldwork agencies to par-ticipate in a simulation study. These patients had not participated in the qualitative phase. The simulation study aimed to quantify the impor-tance of different insulin pen features to patients, quantify patient percep-tions of these pens, and quantify prescribers’ perceptions of what patients feel is important in insulin pens.

At the start of the study, patients who provided written informed consent were asked to complete a sociodemographic form and a questionnaire to rate the importance of pen features identified in phase 1. Patients were then asked to simulate the preparation and delivery of insu-lin using SoloSTAR, KwikPen, and FlexPen disposable pens. For each device in turn, patients were asked to prime the pen (i.e., remove air bubbles that may be in the pen and dial the dose) and then deliver 20

units of insulin into an injection pad. The order of device use was rotated through a simultaneous algorithm to minimize order bias. After each simulated injection, patients were asked to complete a questionnaire to rate the features of the pen they had just used.

HCPs were recruited through fieldwork agencies and, after pro-vision of consent, completed an Internet-based sociodemographic form and a questionnaire to rate their perception of the importance of features of insulin pens to their patients. No simulation or pen rat-ing was performed with HCPs. An overview of the process followed for the quantitative phase is provided in Figure 1.

Statistical analysesBecause this was an exploratory study, no power calculations were conducted. Sample sizes were chosen to provide meaningful data from a variety of patient and HCP sub-groups (i.e., insulin-naive patients vs. current insulin users and users of the three different pen types) and therefore to allow subanalyses to be conducted. A target sample of 100 patients, 75 diabetologists, and 75 DNEs was determined; the final sample size of the study was 111 patients, 75 diabetologists, and 76 DNEs. The sample chosen was considered to be sufficient for the exploration of the data.

All analysis variables were assessed descriptively; discrete data were summarized presenting counts and percentages, whereas for continuous data counts, means with standard deviations (SDs), medians, quartiles, and ranges were calculated. To aid interpretation of the descriptive analysis, tests for statistical significance (t tests) were performed at a 5% significance level to assess differences in perceptions of pen design and usability. Summary statistics were performed using SPSS software (version 14, IBM, Armonk, N.Y.).

Study Results

Phase 1: qualitative phase Eight patients (n = 4 insulin-naive, n = 4 pen users) and 10 HCPs (n = 5




Table 1. Characteristics of Patients With Type 2 Diabetes Who Participated in the Quantitative PhaseAll Patients (n = 111) Insulin-Naive Patients (n = 33) Pen Users (n = 78)

Age range (n [%])18–39 years40–59 years60–80 years

5 (5)39 (35)67 (60)

0 (0)8 (24)25 (76)

5 (6)31 (40)42 (54)*

Sex (n [%])MaleFemale

60 (54)51 (46)

18 (55)15 (45)

42 (54)36 (46)

Level of education (n [%])Secondary educationNoncompulsory secondary educationVocation education/trade schoolUniversity degreePostgraduate university degreeOther

81 (73)8 (7)7 (6)

11 (10)3 (3)1 (1)

23 (70)1 (3)2 (6)5 (15)2 (6)0 (0)

58 (74)7 (9)5 (7)6 (8)1 (1)1 (1)

Employment status (n [%])Working full- or part-timeFull-time homemakerStudentRetiredOut of work (because of diabetes)Out of work (not looking for work)Other

27 (24)8 (7)1 (1)

52 (47)9 (8)5 (5)9 (8)

7 (21)1 (3)0 (0)

19 (58)1 (3)2 (6)3 (9)

20 (26)7 (9)1 (1)

33 (42)8 (10)3 (4)6 (8)

Ethnicity (n [%])AsianCaucasian

3 (3)108 (97)

1 (3)32 (97)

2 (3)76 (97)

Comorbidities (n [%])Heart diseaseStrokeRenal failureVisual impairmentDexterity problemsDiabetic foot problemsDiabetic neurological problemsHigh lipid levelsHigh blood pressureOther comorbidities

30 (27)4 (3)4 (3)

41 (36)25 (22)24 (21)5 (4)

61 (54)58 (52)38 (34)

9 (27)0 (0)0 (0)

15 (45)4 (12)6 (18)0 (0)

19 (57)19 (57)9 (27)

21 (26)4 (5)4 (5)

26 (33)21 (26)18 (23)5 (6)

42 (53)39 (50)29 (37)

Living circumstances (n [%])Living aloneLiving with partnerLiving with partner and childrenLiving with childrenOther

32 (29)52 (47)18 (16)7 (6)2 (2)

10 (30)15 (46)3 (9)4 (12)1 (3)

22 (28)37 (48)15 (19)3 (4)1 (1)

Duration of diabetesMean (SD) duration in monthsDuration < 12 years (144 months) (n [%])Duration ≥ 12 years (144 months) (n [%])

139.3 (91.41)63 (57)47 (42)

104.7 (64.08)26 (78)7 (21)

154.1 (97.53)37 (48)40 (51)*

Number of injections per dayMean SDRange (minimum–maximum)

NANANA

NANANA

3.61.481–11

*Significant difference in insulin-naive patient population and pen users (t test P < 0.05).NA, not applicable; SD, standard deviation



specialists, n = 5 DNEs) participated in the qualitative questionnaire development phase.

After qualitative thematic analy-sis39 according to a predefined coding frame, several changes were made to the original 18-item question-naire.38 Three items were added to the questionnaire after their impor-tance as attributes was highlighted: “how well you can grip it,” “hear the clicks as you dial the dose,” and “tell how much is left in the cartridge.” Other items were expanded to provide further detail (e.g., “its size” was expanded into three items “its length,” “its width,” and “its diam-eter”; and “changing the pen needle” was changed to “putting on the pen needle,” “taking off the needle cap,” and “taking off the needle [after injection]”). Some items were deleted because of perceived redundancy or irrelevance to the quantitative study. Further changes were made to the wording of items to increase clar-ity and avoid misinterpretation of statements.

Finally, statements within the questionnaires were re-ordered to match the process followed when patients use the prefilled insulin pens. The final questionnaire was 26 items long and included 14 items on design and 12 items on usability. Two versions of this questionnaire were created:1. The “importance questionnaire,”

through which respondents rated the importance of design and usability features of prefilled insulin pens for the delivery of prandial insulin on a scale of 1 to 10 (where 1 was “not at all important” and 10 was “extremely important”). This questionnaire had different introductory text for insulin-naive patients, current pen users, and HCPs, although the items were the same. The questionnaire was designed so that patients could rate the importance of the features to them personally and HCPs could answer with refer-ence to what they believed is important to their patients (rather than to themselves).

2. The “rating questionnaire,” through which respondents

evaluated each pen on the same features on a scale of 1 to 10 (where 1 was “extremely dislike” [design questions] or “extremely difficult” [usability questions] and 10 was “extremely like” [design questions] or “extremely easy” [usability questions]). Because they used the same items, the rating questionnaire could be mapped directly to the impor-tance questionnaire. In addition, patients were asked to rank the three pens overall to provide their preferred choice of pens.

Phase 2: quantitative phaseA total of 111 patients (33 insulin-naive and 78 current prefilled pen users) with a mean age of 60 years completed the quantitative phase. Overall, 54% were male, 97% were Caucasian, and close to 50% were retired. Thirty-six percent of patients had visual impairment. Sixty-eight percent used concomi-tant oral antihyperglycemic agents. Approximately 50% had hypercho-lesterolemia or hypertension (Table 1). There were only two significant differences between the patient groups, related to the duration of diabetes (significantly more patients with a duration of diabetes > 12 years in the group of current pen users) and the number of patients aged 60–80 years (higher in the group of current pen users).

Among pen users (n = 78, 70.2%), the mean number of injections per day was 3.6 (SD 1.48, range 1–11). The average number of units per injection varied depending on type of insulin administered, but overall for the first injection (n = 78) was 24.4 (SD 17.87, range 3–80) and for the

second injection (n = 76) was 34.2 (SD 38.78).

A total of 151 HCPs com-pleted the quantitative phase, 50% of whom were diabetolo-gists (n = 75) and 50% were DNEs (n = 76) (Table 2).

Importance of usability featuresAmong patients, the importance of usability features was largely similar between insulin-naive patients and experienced pen users, with the two most important usability features for both groups being knowledge that the entire dose was delivered (mean score 9.3, SD 1.29, out of 10, where 10 was “extremely important”) and ability to read the dose (mean score 9.1, SD 1.26). All other usability features (in terms of ease of use) were also considered important to patients; the items with the lowest score in both groups (priming the pen and replacing the pen cap) still had scores on average closer to the “extremely important” anchor (score of 10) than to “not at all important” (score of 1) (mean scores 7.6, SD 2.3, and 7.2, SD 2.37, respectively) (Table 3).

The only statistically significant difference between non-naive and naive patients was in being able to hear the clicks when they dialed the dose; experienced pen users did not rate this feature to be as important as naive patients (7.0 [SD 2.74] vs. 8.8 [SD 1.52], P < 0.05). Although not statistically significant, naive patients ranked most usability features to be more important than experienced pen users, with the exception of putting the needle on the pen (8.6 for both) and applying the force to inject (8.6 [SD 1.81] for pen users

Table 2. HCP Characteristics (Quantitative Research)

Variable Diabetologists (n = 75) DNEs (n = 76)

Primary practice base (n [%])

Teaching/university 47 (63) 31 (41)

Patient consultation in clinic 28 (37) 45 (59)

Mean number of patients per month (n [range])

281 (80–1,000) 136 (20–1,000)

Mean number of patients with type 2 diabetes per month (n [range])

141 (40–700) 103 (20–800)



Table 3. Importance Scores and Ranking of Features by Importance (Ordered From Most to Least Important, by Mean Patient Score)

Feature Overall Patient

Ranking of Mean

Importance (1–26)

Patients(mean score on 1–10 scale

[SD])

Overall HCP

Ranking of Mean

Importance (1–26)

HCPs(mean score on 1–10 scale [SD])

Insulin-Naive

(n = 33)

Pen Users

(n = 78)

All Patients (n = 111)

Diabetologists (n = 75)

DNEs (n = 76)

All HCPs (n = 151)

Knowing that you have injected the entire dose

1 9.7(0.59)

9.2(1.46)

9.3(1.29)

1 8.7(1.24)

9.6*(0.85)

9.2(1.16)

Reading the dose

2 9.2(1.18)

9.1(1.31)

9.1(1.26)

2 8.5(1.21)

9.6*(0.69)

9.1(1.13)

Correcting if you over-dial

3 9.2(1.06)

8.9(1.44)

9.0(1.34)

3 8.3(1.55)

9.5*(0.74)

8.9(1.34)

Putting the needle on the pen

4 8.6(1.84)

8.6(1.42)

8.6(1.54)

9 7.9(1.14)

8.5*(1.43)

8.2†(1.33)

Knowing how much is left in the pen cartridge

5 8.9(1.81)

8.4(1.91)

8.5(1.88)

7 7.8(1.55)

9.0*(1.29)

8.4(1.53)

Dialing a dose of insulin

5 8.7(1.94)

8.4(1.82)

8.5(1.85)

5 8.0(1.38)

9.2*(1.07)

8.6(1.36)

Taking the needle off after you have injected

5 8.6(1.43)

8.4(1.90)

8.5(1.77)

8 7.7(1.54)

8.8*(1.18)

8.3†(1.47)

Applying the force to inject

5 8.2(2.13)

8.6(1.81)

8.5(1.90)

4 8.1(1.35)

9.5*(0.74)

8.8(1.28)

How well you can grip it when using it

9 8.6(1.94)

8.4(1.78)

8.5(1.82)

6 8.2(1.3)

8.8*(1.45)

8.5(1.41)

Taking off the needle cap

10 8.2(2.13)

8.3(1.68)

8.3(1.82)

12 7.5(1.3)

8.4*(1.52)

7.9(1.48)

Its robustness/durability

11 8.4(2.12)

7.8(1.97)

8.0(2.03)

11 8.1(1.33)

8.2(1.58)

8.1(1.46)

How it feels in your hand when using it

11 7.4(2.76)

7.8(2.04)

7.7(2.27)

12 7.6(1.4)

8.2*(1.77)

7.9(1.61)

Hearing the clicks as you dial the dose

13 8.8(1.52)

7.0*(2.74)

7.6†(2.57)

9 7.8(1.39)

8.5*(1.34)

8.2(1.41)

Priming the pen

13 7.8(2.16)

7.5(2.36)

7.6(2.30)

16 7.2(1.57)

8.0*(1.7)

7.6(1.69)

Ease of carrying it with you

15 7.8(2.66)

7.5(2.48)

7.6(2.53)

15 7.8(1.49)

7.5(1.92)

7.7(1.72)

How well the pen cap fits

16 7.4(2.89)

7.4(2.50)

7.4(2.61)

19 7.4(1.38)

7.3(1.95)

7.3(1.69)

continued on p. 22



vs. 8.2 [SD 2.13] for naive patients) (Table 3).

When examining results by demographic group, importance rankings for “hearing the clicks as you dial” were significantly higher for patients > 60 years of age (n = 65) than for younger patients (n = 46) (8.0 [SD 2.43] vs. 7.0 [SD 2.68], P < 0.05) and for female patients (n = 60) compared to male patients (n = 51) (8.2 [SD 2.02] vs. 7.0 [SD 2.86], P < 0.05). Female patients also ranked the following param-eters significantly higher than males: “dialing a dose of insulin” (9.0 [SD

1.34] vs. 8.1 [SD 2.13], P < 0.05), “taking the needle off after you have injected” (8.8 [SD 1.38] vs. 8.2 [SD 2.01], P < 0.05), and “replacing the pen cap” (7.8 [SD 2.11] vs. 6.8 [SD 2.48], P < 0.05). Patients with visual impairment (n = 41) scored “hear-ing the clicks as you dial the dose” as significantly more important than patients without visual impair-ment (n = 70) (8.2 [SD 2.27] vs. 7.2 [SD 2.68], P < 0.05). There were no significant differences in the impor-tance scores between patients with different levels of education or work status.

Statistically significant differ-ences (P < 0.05) were noted between DNEs (n = 76) and diabetologists (n = 75) across all usability features, with DNEs consistently rating pen usability features as being of greater importance to patients. However, when the scores for each usability feature were ranked in order of importance, results were similar: as with patients, both DNEs and diabe-tologists ranked “knowing the entire dose has been administered” and “reading the dose” as being the most important usability features, whereas “priming the pen” and “replacing

Table 3. Importance Scores and Ranking of Features by Importance (Ordered From Most to Least Important, by Mean Patient Score)

Feature Overall Patient

Ranking of Mean

Importance (1–26)

Patients(mean score on 1–10 scale

[SD])

Overall HCP

Ranking of Mean

Importance (1–26)

HCPs(mean score on 1–10 scale [SD])

Insulin-Naive

(n = 33)

Pen Users

(n = 78)

All Patients (n = 111)

Diabetologists (n = 75)

DNEs (n = 76)

All HCPs (n = 151)

Replacing the pen cap

17 7.8(2.21)

7.0(2.40)

7.2(2.37)

16 7.3(1.53)

7.9*(1.71)

7.6(1.65)

Its discreet-ness when using it

18 7.2(2.90)

6.8(2.73)

6.9†(2.77)

19 7.5(1.66)

7.5(1.98)

7.5(1.82)

Its discreetness in carrying it with you

19 7.3(2.78)

6.6(2.63)

6.8†(2.68)

16 7.7(1.39)

7.5(1.98)

7.6(1.71)

How far the dose button sticks out to dial 40 units

20 6.8(2.84)

6.3(2.93)

6.4†(2.90)

12 7.3(1.87)

8.6*(1.63)

7.9(1.86)

Number of turns it takes to dial 40 units

21 6.3(3.17)

6.0(2.71)

6.0†(2.84)

19 7.2(1.72)

7.7(1.78)

7.5(1.76)

Its length 22 5.6(2.98)

5.7(2.81)

5.7†(2.85)

22 6.7(1.56)

6.8(2.15)

6.8(1.88)

Its width 23 5.3(2.92)

5.6(2.83)

5.5†(2.84)

24 6.6(1.49)

6.6(2.13)

6.6(1.84)

Its weight 24 6.0(3.17)

5.4(2.91)

5.6†(2.99)

23 6.7(1.62)

6.7(2.03)

6.7(1.83)

Its exterior design

25 4.1 (3.06) 4.8 (3.14)

4.6†

(3.12)25 6.6

(1.85)6.0*

(2.09)6.3

(2.0)

Its color 26 3.3(2.78)

4.0(2.98)

3.8†(2.93)

26 5.5(2.08)

5.0(2.07)

5.3(2.08)

Note: Grey rows denote the design features of the pens; white rows reflect usability features. Rating scale: 1 (not at all important) to 10 (extremely important). *Significant difference in scores between patient type or HCP type (t test P < 0.05).†Significant difference in scores between all patients and all HCPs (t test P < 0.05).



Table 4. Mean Patient Scores for Each Pen, With Rankings (Based on Mean Score) Among Pens (all patients, n = 111; scale of 1 [extremely difficult/extremely dislike] to 10 [extremely easy/extremely like])

Importance (by Mean

Patient Score from Table 3)

Feature

KwikPen SoloSTAR FlexPen

Ranking Versus Other Pens

Mean Score (SD)


Mean Score (SD)

Ranking Versus

Other Pens

Mean Score (SD)

1 Knowing that you have injected the entire dose

1 8.9(1.57)

2 8.6(1.83)

3 8.4*(2.08)

2 Reading the dose 1 9.0(1.45)

2 8.8(1.54)

1 9.0(1.50)

3 Correcting if you over-dial 1 9.0(1.28)

2 8.8(1.61)

2 8.8(1.28)

4 Putting the needle on the pen 1 8.8(1.54)

1 8.8(1.64)

1 8.8(1.47)

5 Knowing how much is left in the pen cartridge

3 8.8(1.51)

1 8.5(2.04)

2 8.4(2.06)

5 Dialing a dose of insulin 1 8.9(1.65)

3 8.9(1.45)

2 8.7(1.74)

5 Taking the needle off after you have injected

1 8.1(2.25)

3 7.7(2.70)

2 7.9(2.58)

5 Applying the force to inject 2 7.9(2.27)

3 7.8(2.49)

1 8.0(2.32)

9 How well you can grip when using it

1 8.0(2.04)

3 8.0(2.17)

1 7.9(2.04)

10 Taking off the needle cap 2 8.8(1.46)

2 8.8(1.73)

1 8.9(1.54)

11 Its robustness/durability 3 8.0(1.75)

2 8.2(1.71)

1 8.1(1.62)

11 How it feels in your hand when using it

1 8.0(1.95)

3 8.0(2.09)

1 8.0(1.83)

13 Hearing the clicks as you dial the dose

2 8.7(1.74)

3 8.5(1.95)

1 8.8(1.64)

13 Priming the pen 1 8.9(1.37)

2 8.6(1.75)

2 8.6(1.73)

15 Ease of carrying it with you 3 7.9(1.95)

2 8.2(1.75)

1 8.0(1.73)

16 How well the pen cap fits 1 8.0(1.99)

3 8.3(1.73)

1 8.3(1.79)

17 Replacing the pen cap 1 9.1(1.40)

2 8.9(1.52)

2 8.9(1.79)

18 Its discreetness when using it 1 7.5(2.20)

3 7.5(2.13)

1 7.6(1.96)

19 Its discreetness in carrying it with you

1 7.6(2.11)

3 7.7(2.11)

2 7.8(1.88)

20 How far the dose button sticks out to dial 40 units

2 8.0(1.98)

2 7.8(2.10)

1 7.8(1.79)

21 Number of turns it takes to dial 40 units

2 8.2(1.84)

3 8.0(1.98)

1 7.9(1.86)

continued on p. 24



the pen cap” were seen as the least important (Table 3).

There were few significant differ-ences in the scores for the usability features between patients and HCPs. Of note was that patients scored the importance of putting the needle on the pen significantly higher than HCPs (8.6 [SD 1.54] vs. 8.2 [SD 1.33], respectively, P < 0.05). Taking the needle off after injection was also scored as significantly more impor-tant by patients compared to HCPs (8.5 [SD 1.77] vs. 8.3 [SD 1.47], respectively, P < 0.05) (Table 3).

Importance of design featuresPatients generally scored design fea-tures as less important than usability features, with the exception of “how well you can grip while using it” (mean score 8.4 [SD 1.78]), pen robustness or durability (mean score 7.8 [SD 1.97]), and “how it feels in your hand when using it” (mean score 7.8 [SD 2.04]), which were the three most important design features to patients (Table 3). Female patients scored the importance of several fea-tures significantly higher than males: “its discreetness in carrying it with you” (7.6 [SD 2.28] vs. 6.1 [SD 2.83], P < 0.05), “its discreetness when using it” (8.1 [SD 1.85] vs. 6.0 [SD 3.04], P < 0.05), and “how it feels in your hand when using it” (8.2 [SD

1.84] vs. 7.2 [SD 2.50], P < 0.05). Patients with visual impairment also scored the importance of three design features significantly higher than those who did not have visual impairment: “how it feels in your hand when using it” (8.2 [SD 2.10] vs. 7.3 [SD 2.31], P < 0.05), “how far the dose button sticks out to dial 40 units” (7.2 [SD 2.81] vs. 6.0 [SD 2.87], P < 0.05), and “the number of turns it takes to dial 40 units” (6.9 [SD 2.78] vs. 5.6 [SD 2.77], P < 0.05). There were no significant differences in scores by age, different levels of education, or work status.

HCPs’ perceptions of the importance of different design features to patients were largely similar to patients’ own rankings of importance.

Patient scoring of each pen against key featuresAfter testing the pens in the simula-tion exercise, patients scored each pen on each of the key features. Findings are detailed in Table 4, along with the ranking compared to the other pens for each usability or design feature.

The FlexPen scored significantly lower than the other two pens on the attribute “knowing if you have injected the entire dose” (paired t test, P < 0.05). No other significant

differences among the pens were noted in usability or design. The KwikPen scored highest on more of the usability features compared to the FlexPen and the SoloSTAR (5 vs. 3 and 0, respectively, out of 12). The SoloSTAR scored highest on more of the design features (7 vs. 2 and 2, out of 14).

When asked to rank the pens overall in terms of preference, cur-rent pen users were more likely to prefer their own pens to competitor pens (Figure 2).

However, when results are viewed for the whole patient population (n = 111), including both insulin-naive patients and current pen users, the mean ranking (from 1 to 3) of each of the pens was similar (KwikPen, 2.0; FlexPen, 2.1; and SoloSTAR, 1.9).

Discussion The development of insulin pens represents an important achievement in the management of diabetes, with 77% of patients reporting that pen devices facilitate adherence with their regimen.40 However, delay to progression of insulin therapy and nonadherence to therapy is an ongoing and increasing problem.16,41 It is therefore important to under-stand patients’ views on all of the components of insulin delivery,

Table 4. Mean Patient Scores for Each Pen, With Rankings (Based on Mean Score) Among Pens (all patients, n = 111; scale of 1 [extremely difficult/extremely dislike] to 10 [extremely easy/extremely like])

Importance (by Mean

Patient Score from Table 3)

Feature

KwikPen SoloSTAR FlexPen


Mean Score (SD)


Mean Score (SD)

Ranking Versus

Other Pens

Mean Score (SD)

22 Its length 3 7.8(1.89)

2 7.9(1.92)

1 7.7(1.77)

23 Its width 3 7.6(2.18)

1 7.9(2.00)

1 7.7(1.82)

24 Its weight 3 7.8(2.02)

1 7.9(1.92)

1 7.8(1.85)

25 Its exterior design 3 7.6(2.25)

2 7.9(1.90)

1 7.8(1.95)

26 Its color 3 7.6(2.34)

2 7.9(1.99)

1 7.7(1.91)

Note: Grey rows denote the design features of the pens; white rows reflect usability features.*Significant difference in scores between pens (t test P < 0.05).

Table 4. Mean Patient Scores for Each Pen, With Rankings (Based on Mean Score) Among Pens (all patients, n = 111; scale of 1 [extremely difficult/extremely dislike] to 10 [extremely easy/extremely like]),

continued from p. 23



including the insulin delivery device, to enable steps to address the issue of nonadherence. This study sought to understand the relevant features of prefilled disposable insulin pens from the perspectives of insulin-naive patients and current pen users, in addition to HCPs’ perceptions of what is important to their patients. Attributes tested were based on a design and usability questionnaire adapted, with patient and HCP input, from Haak et al.38

The three most important features to patients all relate to the usability of the pen: knowing the entire dose has been injected, reading the dose correctly, and correcting if the dose is over-dialed. It is also note-worthy that these are the top three features that HCPs (both DNEs and physicians) perceived to be most important to patients. This suggests that HCPs understand patient prefer-ences and therefore may be able to adjust their prescribing decisions to meet these preferences.

Few significant differences were noted between HCP specialties. Although there were few discernible differences between what was per-ceived as important to current pen users and to insulin-naive patients, importance scores for current pen users tended to be lower. Although HCPs perceived design features to be significantly more important to patients than patients themselves indicated, further analysis revealed

that, although the importance score attributed to a particular feature was significantly different, the rela-tive importance of that feature was similar. Therefore, it is important that the scores given to the differ-ent usability and design features be considered within the context of the ranking with other features.

As a second objective, this study aimed to elicit patients’ and HCPs’ perceptions of prandial insulin delivery when simulating an injection using three prefilled disposable pens: SoloSTAR, KwikPen, and FlexPen. After the simulation, patients were asked to score each of the three pens on their usability and design features.

Only one significant difference was noted among the pens; fur-thermore, the absolute difference between the scores for each pen was very similar, as every feature was ranked > 7 on a 1–10 scale. In terms of usability, the KwikPen ranked as the top pen of the three examined, and the highest design scores were given to the SoloSTAR. Overall, usability features appear to be of greater importance than design features (such as width, color, length, design, and weight) to adult patients with type 2 diabetes. This is also recognized by HCPs.

Findings from this study are consistent with and augment find-ings from previous studies examining patient preferences with insulin

pen use.42–44 Our results highlight the importance patients place on knowing that the entire dose has been injected, reading the dose cor-rectly, and correcting if the dose is over-dialed.

The fact that these three fea-tures were the most important to patients would appear to support previous reports that the majority of patients using vial-and-syringe insulin delivery may incorrectly administer insulin because of timing and dosing errors.42–44 A previous study38 found that patients consid-ered insulin pens to be more socially acceptable than vials and syringes. This study confirms that patients feel aspects of social acceptability are an important design feature of insulin pens (patients’ overall mean score for a pen’s discreteness in carrying it and using it were both 7.0 on a 1–10 scale). However, patients considered other features, primarily related to usability, to be more important than the discreetness of the insulin pens.

It is important to note that patients also find glucose control, cardiovascular risk, and weight gain to be key features to consider when deciding whether to choose a glu-cose-lowering therapy.42 This was not evaluated in the current simulation study, but it is likely that an under-standing of patients’ perceptions and expectations about glucose control and side effects, as well as their needs regarding key pen features, will affect adherence.

When asked for an overall rank-ing of the pens, more than 50% of patients who were previous pen users ranked their own pen as the preferred choice. There is a poten-tial bias in the scores toward pens already used by individual patients that may result from familiarity with a specific pen (patients in this study were asked to simulate only one injection with each pen) and that may limit the generalizability of findings.

However, these results also highlight the implications of pen preference as a barrier to switching insulin delivery device, if required. Further research will be valuable to understand the requirements for switching insulin delivery devices

Figure 2. Pens ranked as the preferred choice (ranking of 1 when asked for overall ranking of pens).



in patients with type 2 diabetes and any barriers to doing so in relation to patient preferences for pen features (usability and design).

We identified more statistically significant differences (P < 0.05) between DNEs and diabetologists than between insulin-naive patients and pen users. This could be par-tially the result of different sample sizes (75 DNEs vs. 76 diabetolo-gists compared to 33 insulin-naive patients vs. 78 pen users). HCPs were not asked whether they themselves had diabetes; however, it is unlikely that this would have confounded results given that the questionnaire clearly asked what pen features they deemed to be important for their patients.

Although this study provides useful data regarding patient prefer-ences and the preferences that HCPs perceive their patients to have, there are a number of limitations to con-sider. The study focused on patients with type 2 diabetes and was limited to the delivery of prandial insulin. Therefore, the results are not general-izable to patients with type 1 diabetes (recent research has highlighted the need to improve and refine the func-tionality of insulin pen devices for use in children and adolescents45), to other types of insulin regimens (e.g., basal insulin or premixed insulin), or to reusable pens.

Although the overall patient sample size was large enough to perform many of the comparisons of interest (e.g., experienced pen users compared to insulin-naive patients), the small subsets of patients using the different types of pens (e.g., only 20 SoloSTAR users were included) prevented further analyses to determine differences in design and usability scores by insulin pen brands. Furthermore, the sample was one of convenience, and the gener-alizability is unknown. The patient characteristics were as expected, although the study purposefully over-sampled people with visual impairment (36%)46 to gain an understanding of whether patients with vision problems place differing emphasis on the importance of vari-ous pen features than those without visual impairments.

Because the numbers of patients using the different pen brands dif-fered, the higher ratings for patients’ “own” pens may have introduced a bias in ratings for those pen brands that had a greater proportion of users in the study. It is important to note that we did not adjust for mul-tiple comparisons because this was meant to be a descriptive study.

The study used newly developed questionnaires (based on an exist-ing questionnaire38) that, although content-valid, have not undergone psychometric testing. However, given that the questionnaires were reviewed at an item-by-item level, the results can still be considered scientifically robust. Nevertheless, future work to assess the reliability and validity of the questionnaires used would be valuable.

This study found few differences between insulin-naive patients and experienced pen users. However, this was a cross-sectional study. Further research examining how patients’ perceptions change over time as they move from being insulin-naive to becoming experienced insulin users may provide additional insights. Linking such information to adher-ence and satisfaction may also provide added benefit to HCPs when making prescribing decisions.

Our study asked patients to rate the importance of features and asked HCPs to rate the importance of fea-tures from their patients’ perspective. Future work could examine what HCPs themselves find important when prescribing and then compare this to patients’ perceptions. This study shows that HCPs have a clear understanding of what is important to patients, but it would be useful to examine what they themselves find important and whether their impor-tance criteria differ from those of patients.

Future research into patient-reported outcomes in diabetes focusing on insulin delivery sys-tems should consider the results of this study (in terms of the features that were important to patients and also the questionnaires used) when designing protocols. Future research may also wish to explore the demographic and clinical variables

associated with pen preference in more detail, using, for example, mul-tivariate modeling or multi-attribute utility theory analysis to determine preferences. This would provide further evidence regarding the sig-nificance of the findings of a similar study and may help to identify groups of patients for whom certain features are more important, thereby enabling physicians to recommend the most appropriate pen for their patients.

Patient preferences elicited from this research have highlighted certain pen usability and design features that are of importance to patients. Their preferences can be used to identify which of the existing insulin pens (and those in development) have these features to aid physicians in ensuring that they choose the most appropriate pens for their patients.

In a recent review of the link between satisfaction and adherence, 20 studies were found to show a positive association between treat-ment satisfaction and adherence, compliance, or persistence. The most satisfied patients were the most compliant or persistent, and the least satisfied were the least compliant or persistent.47 In an observational study on subcutaneous versus oral treatment for iron chelation therapy, greater satisfaction in the oral treatment group was found and “never thinking about stopping treatment” was associated with less treatment burden,48 indicating the importance and relevance of delivery device features in patient adher-ence. Better understanding patient preferences may ultimately lead to greater patient adherence to insulin therapy, an important issue given the clinical and economic conse-quences of nonadherence. Future research examining predictive factors in patient preferences and the link between preference and adherence is warranted.

AcknowledgmentsThis study was sponsored by and designed and conducted in part by Eli Lilly, the manufacturers of the KwikPen. Authors Gregg, Abetz, Hermanns, and Reaney designed and conducted the research. Authors



Heron, Gregg, Abetz, and Reaney interpreted results. Authors Heron and Abetz developed the manuscript, and authors Reaney, Hermanns, and Gregg provided critical comments on the manuscript drafts. All authors finalized and approved the manu-script. The authors acknowledge the assistance of Helen Smith and Lauren Lee in developing the study design and manuscript, respectively.

References1International Diabetes Federation: Diabetes Atlas. Available from http://www.idf.org/diabetesatlas. Accessed 1 June 2011 2International Diabetes Federation: Diabetes: the policy puzzle: is Europe making progress? [article online] Available from https://www.idf.org/sites/default/files/EU-diabetes-policy-audit-2008%20-2nd%20edition.pdf. Accessed 22 November 2012 3Nathan DM, Buse JB, Davidson MB, Ferrannini E, Holman RR, Sherwin R, Zinman B: Medical management of hyper-glycemia in type 2 diabetes: a consensus algorithm for the initiation and adjust-ment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes. Diabetes Care 32:193–203, 20094U.K. Prospective Diabetes Study Group: Intensive blood glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complica-tions in patients with type 2 diabetes (UKPDS 33). Lancet 352:837–853, 19985Ziemer DC, Miller CD, Rhee MK, Doyle JP, Watkins C Jr, Cook CB, Gallina DL, El-Kebbi IM, Barnes CS, Dunbar VG, Branch WT Jr, Phillips LS: Clinical inertia contrib-utes to poor diabetes control in a primary care setting. Diabetes Educ 31:564–571, 20056Phillips LS, Branch WT, Cook CB, Doyle JP, El-Kebbi IM, Gallina DL, Miller CD, Ziemer DC, Barnes CS: Clinical inertia. Ann Intern Med 135:825–834, 20017Berlowitz DR, Ash AS, Glickman M, Friedman RH, Pogach LM, Nelson AL, Wong AT: Developing a quality measure for clinical inertia in diabetes care. Health Serv Res 40:1836–1853, 20058Vigersky RA: An overview of management issues in adult patients with type 2 diabetes mellitus. J Diabetes Sci Technol 5:245–250, 20119Parchman ML, Pugh JA, Romero RL, Bowers KW: Competing demands or clinical inertia: the case of elevated glycosylated hemoglobin. Ann Fam Med 5:196–201, 200710Grant R, Adams AS, Trinacty CM, Zhang F, Kleinman K, Soumerai SB, Meigs JB, Ross-Degnan D: Relationship between patient medication adherence and subsequent clinical

inertia in type 2 diabetes glycemic manage-ment. Diabetes Care 30:807–812, 200711Leslie CA, Satin-Rapaport W, Matheson D, Stone R, Enfield G: Psychological insulin resistance: a missed diagnosis. Diabetes Spectrum 7:52–57, 199412Hayes RP, Fitzgerald JT, Jacober SJ: Primary care physician beliefs about insulin initiation in patients with type 2 diabetes. Int J Clin Pract 62:860–868, 200813Crasto W, Jarvis J, Khunti K, Davies MJ: New insulins and new insulin regimens: a review of their role in improving glycaemic control in patients with diabetes. Postgrad Med J 85:257–267, 200914Meneghini L, Artola S, Caputo S, Damci T, Dzida G, Kaiser M, Khunti K, Liebl A, Ligthelm R, Maran A, Orozco-Beltran D, Ross S, Yale JF: Practical guidance to insulin management. Prim Care Diabetes 4 (Suppl. 1):S43–S56, 201015Liebl A, Jones S, Benroubi M, Castell C, Goday A, Aline CM, Smith HT, Nicolay C, Simpson A: Clinical outcomes after insulin initiation in patients with type 2 diabetes: 6-month data from the INSTIGATE observa-tional study in five European countries. Curr Med Res Opin 27:887–895, 201116Holman RR, Farmer AJ, Davies MJ, Levy JC, Darbyshire JL, Keenan JF, Paul SK: Three-year efficacy of complex insulin regimens in type 2 diabetes. N Engl J Med 361:1736–1747, 200917Benroubi M: Fear, guilt feelings and misconceptions: Barriers to effective insulin treatment in type 2 diabetes. Diabetes Res Clin Pract 93 (Suppl. 1):S97–S99, 201118Snoek FJ, Skovlund SE, Pouwer F: Development and validation of the insulin treatment appraisal scale (ITAS) in patients with type 2 diabetes. Health Qual Life Outcomes 5:69, 200719Hermanns N, Mahr M, Kulzer B, Skovlund SE, Haak T: Barriers towards insulin therapy in type 2 diabetic patients: results of an obser-vational longitudinal study. Health Qual Life Outcomes 8:113, 201020Petrak F, Stridde E, Leverkus F, Crispin AA, Forst T, Pfutzner A: Development and validation of a new measure to evaluate psychological resistance to insulin treatment. Diabetes Care 30:2199–2204, 200721Polonsky WH, Fisher L, Guzman S, Villa-Caballero L, Edelman SV: Psychological insulin resistance in patients with type 2 diabetes: the scope of the problem. Diabetes Care 28:2543–2545, 200522Sabate E: Adherence to Long-Term Therapies: Evidence for Action. Geneva, Switzerland, World Health Organization, 2003. Available from www.who.int/chp/knowledge/publica-tions/adherence_introduction.pdf. Accessed 22 November 201223Cramer JA: A systematic review of adher-ence with medications for diabetes. Diabetes Care 27:1218–1224, 2004

24Lee WC, Balu S, Cobden D, Joshi AV, Pashos CL: Prevalence and economic conse-quences of medication adherence in diabetes: a systematic literature review. Manag Care Interface 19:31–41, 200625Evans JM, Donnan PT, Morris AD: Adherence to oral hypoglycemic agents prior to insulin therapy in type 2 diabetes. Diabet Med 19:685–688, 200126Ho PM, Rumsfeld JS, Masoudi FA, McClure DL, Plomondon ME, Steiner JF, Magid DJ: Effect of medication nonadher-ence on hospitalization and mortality among patients with diabetes mellitus. Arch Intern Med 166:1836–1841, 200627Gibson TB, Song X, Alemayehu B, Wang SS, Waddell JL, Bouchard JR, Forma F: Cost sharing, adherence, and health outcomes in patients with diabetes. Am J Manag Care 16:589–600, 201028Pladevall M, Williams LK, Potts LA, Divine G, Xi H, Lafata JE: Clinical outcomes and adherence to medications measured by claims data in patients with diabetes. Diabetes Care 27:2800–2805, 200429Nunes V, Nielson J, O’Flynn N, Calvert N, Kuntze S, Smithson H, Benson J, Blair J, Bowser A, Clyne W, Crome P, Haddad P, Hemmingway S, Horne R, Johnson S, Kelly S, Packham B, Patel M, Steel J: Clinical guidelines and evidence review for medicines adherence: involving patients in decisions about prescribed medicines and supporting adherence. London, National Collaborating Centre for Primary Care and Royal College of General Practitioners, 2009. Available from http://www.nice.org.uk/nicemedia/live/11766/42971/42971.pdf. Accessed 19 November 201230DCCT Research Group: The effect of inten-sive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 329:977–986, 199331Hansen RA, Farley JF, Droege M, Maciejewski ML: A retrospective cohort study of economic outcomes and adherence to monotherapy with metformin, pioglitazone, or a sulfonylurea among patients with type 2 diabetes mellitus in the United States from 2003 to 2005. Clin Ther 32:1308–1319, 201032Molife C, Lee LJ, Shi L, Sawhney M, Lenox SM: Assessment of patient-reported outcomes of insulin pen devices versus conventional vial and syringe. Diabetes Technol Ther 11:529–538, 200933Korytkowski M, Niskanen L, Asakura T: FlexPen: addressing issues of confidence and convenience in insulin delivery. Clin Ther 27 (Suppl. B):S89–S100, 200534Rex J, Jensen KH, Lawton SA: A review of 20 years’ experience with the NovoPen family of insulin injection devices. Clin Drug Investig 26:367–401, 200635Rubin RR, Peyrot M: Quality of life, treat-ment satisfaction, and treatment preference associated with use of a pen device delivering a premixed 70/30 insulin aspart suspen-



sion (aspart protamine suspension/soluble aspart) versus alternative treatment strategies. Diabetes Care 27:2495–2497, 200436Perfetti R: Reusable and disposable insulin pens for the treatment of diabetes: understanding the global differences in user preference and an evaluation of inpatient insulin pen use. Diabetes Technol Ther 12 (Suppl. 1):S79–S85, 201037British Healthcare Business Intelligence Association: Legal & Ethical Guidelines for Healthcare Market Research, October 2011. Available from http://www.bhbia.org.uk/guidelines/legalandethicalguidelines.aspx. Accessed 22 November 2012 38Haak T, Edelman S, Walter C, Lecointre B, Spollett G: Comparison of usability and patient preference for the new disposable insulin device Solostar versus Flexpen, Lilly disposable pen, and a prototype pen: an open-label study. Clin Ther 29:650–660, 200739Joffe H, Yardley L: Research methods for clinical and health psychology. In Research Methods for Clinical and Health Psychology. Marks DF, Yardley L, Eds. London, Sage Publications, 2003, p. 56–6840Graff MR, McClanahan MA: Assessment by patients with diabetes mellitus of two insulin pen delivery systems versus a vial and syringe. Clin Ther 20:486–496, 199841Salas M, Hughes D, Zuluaga A, Vardeva K, Lebmeier M: Costs of medication nonadher-

ence in patients with diabetes mellitus: a systematic review and critical analysis of the literature. Value Health 12:915–922, 200942Hauber AB, Mohamed AF, Johnson FR, Falvey H: Treatment preferences and medica-tion adherence of people with type 2 diabetes using oral glucose-lowering agents. Diabet Med 26:416–424, 200943Coscelli C, Calabrese G, Fedele D, Pisu E, Calderini C, Bistoni S, Lapolla A, Mauri MG, Rossi A, Zappella A: Use of premixed insulin among the elderly: reduction of errors in patient preparation of mixtures. Diabetes Care 15:1628–1630, 199244Newman KD, Weaver MT: Insulin measure-ment and preparation among diabetic patients at a county hospital. Nurse Pract 19:44–45, 48, 199445Hanas R, de Beaufort C, Hoey H, Anderson B: Insulin delivery by injection in children and adolescents with diabetes. Pediatr Diabetes 12:518–526, 201146World Health Organization: Diabetes fact sheet, 2011. Available from http://www.who.int/mediacentre/factsheets/fs312/en. Accessed 22 November 201247Barbosa CD, Balp MM, Kulich K, Germain N, Rofail D: A literature review to explore the link between treatment satisfaction and adherence, compliance, and persistence. Patient Prefer Adherence 6:39–48, 2012

48Rofail D, Abetz L, Viala M, Gait C, Baladi JF, Payne K: Satisfaction and adherence in patients with iron overload receiving iron chelation therapy as assessed by a newly developed patient instrument. Value Health 12:109–117, 2009

Louise Heron, MA, is a research manager, and Linda Abetz, MA, is vice president at Adelphi Values in Bollington, Cheshire, U.K. Matthew Reaney, MSc, is a senior research scientist at Eli Lilly in Windlesham, Surrey, U.K. Norbert Hermanns, PhD, is a professor at the Diabetes Research Institute in Mergentheim, Germany. Laura Gregg, BA, is a project director at Adelphi International Research, in Bollington, Cheshire, U.K.

Notes of disclosure: Mr. Reaney is employed by; Ms. Heron, Ms. Gregg, and Ms. Abetz have received consulting fees from; and Dr. Hermanns serves on an advisory panel for Eli Lilly, which manufactures the KwikPen insulin delivery device.

perceptions of usability and design ... - diabetes spectrummost important features to them in...

Documents