”When an entire country is a cohort”Frank, Science 2000

”The epidemiologist’s dream: Denmark”

Frank, Science 2003

Several important papers

Denmark - The epidemiologist’s dream?

Data landscape

Personal Registration NumberAll Danish citizens are assigned a unique civil registration number (CPR), which enables accurate linkage between these registries.

Danish Civil Registration system, including:• Current and historical information on address in Denmark

(municipality, street, house number) • Information on address is complete from 1971

Data

Danish Civil Registration system, including:• Current and historical information on address in Denmark

(municipality, street, house number) • Information on address is complete from 1971

Strengths of Danish data sources

• Public health care system• Record linkage at the individual level• Time and money saving• Data-collection independent of research question• Large populations and long-term follow up• Liberal data law enabling data access• Relatively inexpensive to get data

Validity

Positive predictive value (%)

Storage of administrativepatient data

Storage of medical patient data

Use of a computer during consultation

Use of a decision support system via a health portal (www.sundhed.dk)

E-mail consultation and renewal of medication

Transfer of medicalpatient data to other carers

Denmark has the worlds’ most “computerised” general practice

Transfer of lab resultsfrom the laboratory

Patients receive resultsfrom laboratory by mail

Sentinel Data capturePC in clinic

PC in clinic

Serverin

clinic

DAMD Server

NIPNational Indicator Project

DAMD Reportserver

Danish healthcare data net

Transferring data from DAMD til NIP

DAMD generates quality feedback reports

GPs have access to reports from their patient group through secure logon

Quality feedback reports are generated individually for each practice on the basis of the accumulated data and available online only for the specific practice.

The feedback reports includes a benchmark section which enables the GP to compare his own quality with other GPs locally and nationally.

pop-up

Proportion of diabetes patients, percent

HbA1c, median

Total cholesterol , median

Systolic blood-pressure, median

Percent of patients investigated last year

Percent of patients investigated last year

Percent of patients investigated last year

Percent of patients investigated last yearU-Alb/Crea, median

Wakefield Lancet 1998

Timing of symptoms

MMR and Autism

Vaccination cohortRegistries

Civil Registration system, Central psychiatric Register, National Hospital Register, Medical Birth Register, National Health Service

CohortDanish children born 1991-1998 (N= 537,000)

MMR vaccinated (N=439,251)

OutcomeAutism (N= 316), Autism spectrum disorder (N= 422)

Febrile seizures (N=17,986)

MMR vaccination

Autism Autism spectrum disorder

No

Yes

1.00 (reference)

0.92 (0.68-1.24)

1.00 (reference)

0.83 (0.65-1.07)

MMR and Autism

Does feedback improve diabetes care?• DAMD – Danish General Practice Database (Oct. 2009)

~ 506,000 patients~ 14,500 patients with type 2 diabetes

We included patients with type 2 diabetes with at least twodiabetes recordings (yearly controls) from Oct. 2009 to Oct. 2010

• The number of included patients was 7988;5805 with recorded bloodpressure 7122 with recorded cholesterol levels 

Oct. 2009, N(%)

Oct. 2010, N(%)

Absolute risk reduction (95% CI)

Diabetes control (HbA1c>7% and no antidiabetic medication) 235 (2.94) 127 (1.59)

1.35%(0.89-1.81), p<0.001

Bloodpressure (Systolic>130 and no antihypertensive medication) 722 (12.44) 460 (7.92)

4.51%(3.42-5.61), p<0.001

Cholesterol (>4.5 mmol/l and no cholesterol-lowering medication)

1226 (17.21)

889 (12.48)4.73% (3.56-5.90),

p<0.001

Proportion of patients with values above recommendations among the 7988 included type 2 diabetes patients

(5805 with recorded bloodpressure, 7123 with recorded cholesterol levels)

Results

• BP control rate 33.2% (CI: 32.7-33.7). • BP control rate, diabetes: 16.5% (CI: 15.8-17.3) • BP control rate, comorbidities: 42.9% - 51.4% for

patients with ischemic heart diseases, cerebrovascular or peripheral vascular diseases.

• Other comorbidities such as cancer, psychiatric disease or chronic obstructive pulmonary diseases, never reduced the odds of BP control

Challenges

• Validity of the diagnoses• Missings data

Strengths

• No selection bias• Size matters• Data is collected prosepctively

Data Protection in Denmark• Complies with European Union rules• Waives the need for informed consent when data are

used for ”statistical and scientific purposes of significance to society”

• Stipulates rules for handeling of data• Allows the use of individual information while minimizing• the spread of these data• No breaches after more than thirty years

Informed consent is a cornerstone in all medical research

The Helsinki Declaration: ‘the health of my patient will be my first consideration’ and ‘while the goal of the primary purpose of medical research is to generate new knowledge, this goal can never take precedence over the rights and interests of individual research subjects’.

”If we are using data that already exist and the research can be done with no risk for the people under study, there may well more ethical problems in not doing the research than in doing it. ”

Most countries record births, deaths and several diseases, and some in addition record use of medicine, treatment procedure, diagnostic data etc. Much of this is done without having informed consent.

Getting informed consent after data collection will be difficult, in most cases even impossible.

The existence of these data is a threat to privacy, but not necessarily in the use of the data for research.

No date – no knowledge – no development

Quality assurance

Research

CME

Aerobec Initial analyses

InclusionInitiation cohort EF Total

All 1086 84294

At least 1 outcome ICS

860 61649

1 yr bsl and 1 yr outcome

854 61237

Exclude ICS/LABA FDC*

726 57780

Exclude COPD** 666 54773

No maintenance OS

661 54570

*R03AK07 or 08, **LAMA during baseline or outcome period

Step-up cohort EF Non-EF

All 164 61125

At least 1 outcome ICS

147 51664

1 yr bsl and 1 yr outcome

147 51425

Excluding ICS/LABA FDC*

137 48364

Excluding COPD** 130 45672

No maintenance OS

130 45331

*At least 1 baseline ICS and 50% step-up at index date

Severe exercabationsInitiation Cohort

Non-EF EF Total

No Severe Exer.

48197 (89%) 602 (91%) 48799 (89%)

At least 1 Sev. Exer.

5712 (11%) 59 (9%) 5771 (11%)

Total 53909 (100%)

661 (100%) 54570 (100%)