The Association between blood glucose and length of hospital

stay due to Acute COPD exacerbation

Yusuf Kasirye, Melissa Simpson, Naren Epperla, Steven Yale

Blood glucose and acute COPD Blood glucose and acute COPD exacerbationsexacerbations

● Introduction● Methods● Results● Discussion

IntroductionIntroduction

● Chronic Obstructive Pulmonary Disease (COPD) is the fourth most common cause of death in the United States, affecting ~ 24 million people

● Several studies have looked at hospitalizations due to acute COPD exacerbations (AECOPD) and comorbidities such as diabetes mellitus and metabolic syndrome

● Two studies of hospital admissions found a marginal association between DM and length of hospital stay

● Did not examine blood glucose levels

● Another study found that increased blood glucose is associated with longer hospitalization

● Analyzed highest inpatient BG value only● Looked at length of stay as <9 days (good) compared to

≥ 9 days (bad)

IntroductionIntroduction

IntroductionIntroduction

● The purpose of this study is to examine the association between inpatient blood glucose (BG) levels and the following clinical outcomes in patients hospitalized for AECOPD:

● In hospital complications● Length of hospitalization ● Thirty day re-hospitalization (all cause)● Ninety day mortality (all cause)

MethodsMethods

●Retrospective cohort of 209 patients hospitalized for AECOPD (physician validated) from 1-1-2—4 to 12-31-2008 at St. Joseph’s hospital (Marshfield WI)● Inclusion criteria:●COPD diagnosis (according to GOLD criteria) at some point

prior to index hospitalization●AECOPD diagnosis at admission and discharge●A BG measurement within 6 hours of hospitalization●≥ 2 BG measurements during hospitalization (analyzed

both fasting and random blood glucose measurements)

Study population and design

MethodsMethods

●In-hospital complications: the presence of cardiac, respiratory, neurologic, renal, or septic complications during index hospitalization ●Length of hospital stay: the time from admission

until discharge from hospital, measured in days ●Thirty day readmission: hospitalization for any

cause within 30 days of the discharge date of index hospitalization●Ninety day all cause mortality: death due to any

cause within 90 days of index hospitalization

Outcomes

MethodsMethods●Outcomes modeled as follows:

●LOS: analyzed both as a discrete and categorical (≤2 days vs. > 2 days) outcome

●Thirty day readmission: analyzed as a categorical outcome●Ninety day all-cause mortality: analyzed as a categorical outcome.

●Blood glucose was analyzed as a continuous variable and was calculated as mean per day (ng/ml), odds ratios reported for a 100 ng/ml decrease in BG

●Logistic regression analyses accounting for repeated BG measurement during hospitalization were used for odds ratio estimation (SAS, proc genmod, Cary NC)●Age and DM were forced into adjusted models, other covariates were

included if they had a significance level of ≤ 0.05 or changed the beta estimate for BG by ≥ 10%

Statistical analysis

ResultsResultsIn-hospital complications

Complications during index

hospitalization

No Complications during index

hospitalization Univariate analysis Adjusted analysisCharacteristic: n = 24 n = 185 OR 95% CI p-value OR 95% CI p-valueBlood glucose (100 ng/ml decrease in daily mean) 1.81 0.81-4.05 0.15 1.81 0.95-3.47 0.07

Age (years) at hospital admission - mean (±sd) 67.3(9.5) 64.5(8.1) 1.05 0.99-1.11 0.12 1.08 0.97-1.19 0.15Diabetes Mellitus at hospital admission - n(%) 7(29) 56(30) 0.95 0..37-2.42 0.91 1.06 0.37-3.07 0.92Male sex - n(%) 7(29) 73(39) 0.63 0.25-1.60 0.33Corticosteroids given within 24 hours of hospitalization - n(%) 0(0) 176(96) *Current smoker - n(%) 75(41) 110(59) 0.73 0.30-1.80 0.50Body mass index in kg/m2 - mean (±sd) 32.6(8.7) 31.1(8.8) 1.02 0.97-1.07 0.45 1.08 1.01-1.16 0.02Inhaled medications at the time of presentation - n(%) 20(83) 165(89) 0.61 0.19-1.95 0.40History of chronic steroid use - n(%) 1(4) 21(11) 0.34 0.04-2.63 0.30Received respiratory support during hospitalization - n(%) 5(21) 23(12) 0.54 0.18-1.59 0.26Number of blood glucose measurements taken per day - mean (±sd) 1.7(1.9) 2.6(1.8) 0.66 0.47-0.93 0.02

ResultsResultsLOS

Hospitalization ≤ 2 days

Hospitalization > 2 days Univariate analysis Adjusted analysis

Characteristic: n = 109 n= 100 OR 95% CI p-value OR 95% CI p-value

Blood glucose (100 ng/ml decrease in daily mean) 1.44 1.01-2.04 0.04 1.58 1.09-2.29 0.01

Age (years) at hospital admission - mean (±sd) 64.5(8.5) 65.2(8.1) 1.01 0.98-1.04 0.54 0.97 0.93-1.01 0.18

Diabetes Mellitus at hospital admission - n(%) 32(29) 31(31) 1.08 0.60-1.95 0.80 1.22 0.60-2.50 0.59

Received respiratory support during hospitalization - n(%) 22(18) 6(6) 3.96 0.53-10.23 0.005

Complications during hospitalization - n(%) 20(18) 4(4) 5.39 1.77-16.39 0.003

Male sex - n(%) 42(39) 38(38) 0.98 0.56-1.71 0.94

Corticosteroids given within 24 hours of hospitalization - n(%) 105(97) 95(95) 0.54 0.13-2.33 0.41

Current smoker - n(%) 37(34) 46(46) 1.66 0.95-2.90 0.08

Body mass index in kg/m2 - mean (±sd) 31.4(9.4) 31.1(8.2) 1.00 0.97-1.03 0.80

Inhaled medications at the time of presentation - n(%) 98(90) 87(87) 0.75 0.32-1.76 0.51

History of chronic steroid use - n(%) 12(11) 10(10 0.91 0.37-2.21 0.83

Number of blood glucose measurements taken per day - mean (±sd) 2.3(2.0) 2.7(1.6) 1.13 0.97-1.32 0.12

ResultsResultsLOS

• Unadjusted, BG modeled continuously was not associated with LOS (OR: 1.25, 95% CI: 0.87-1.81, p-value: 0.22)

• Adjusting for age and DM, decreased BG was associated with a longer LOS (OR for 100 ng/ml decrease: 1.39, 95% CI 1.04-1.87, p-value: 0.03)

ResultsResultsThirty day readmission

• Thirty six people were readmitted within 30 days of discharge from index hospitalization

• BG was not associated with 30 day readmission • Unadjusted OR: 1.34, 95% CI: 0.78-2.28, p-value

0.29• Adjusting for DM, age, and BMI: 1.34, 95% CL

0.75-2.41, p-value: 0.33

ResultsResultsNinety day mortality

• Eight people died due to any cause within 90 days of index hospitalization

• BG was not associated with 90 day all cause mortality• Unadjusted OR: 2.68, 95% CI: 0.92-7.79, p-value

0.07• Adjusting for DM, age, and BMI: 1.93, 95% CL

0.55-6.75, p-value: 0.30

ResultsResultsMediation analysis

• Tested how much of the association between in-hospital complications and length of stay could be attributed to BG.• Found that 4% of that association is due to BG (p =

0.07)

DiscussionDiscussion

• Decreased BG has a marginal and weak association with in-hospital complications and longer LOS• BG may be reflective of overall health in this

population• No association with 30 days readmission or

90 day all-cause mortality• BG (as we measured it) probably of little

prognostic utility in AECOPD patients

DiscussionDiscussion

• Different than the study by Baker et al.• May be due to difference in exposure and

outcome definition• Repeated their method on our data and found no

association

DiscussionDiscussion

• Future studies• Employ continuous glucose monitoring to fully

understand the complexities of corticosteroid usage, the glycemic response and clinical outcomes in this group of people

• Study the association between metabolic syndrome and clinical outcomes and how much glycemic status contributes to that association

DisclosureDisclosure

The authors do not have conflicts of interest to report.

This study was funded by a Marshfield Clinic Research Foundation resident research grant.