ADDITION-EUROPE

The Anglo-Danish-Dutch Study of Intensive Treatment In People with Screen-Detected Diabetes in Primary Care (ADDITION) is an international population-based screening and intervention study for type 2 diabetes in general practice.

Primary aim

The study aims to examine the effect of intensive multifactorial treatment (compared to routine treatment) on cardiovascular disease among people with screen-detected type 2 diabetes.

Target population

The target population for diabetes screening is close to 400,000 people (aged 40-69 years). The screening programme differs between countries and targets different risk groups with impaired fasting blood glucose, impaired glucose tolerance or increased cardiovascular disease risk without dysglycemia. 

Included participants

A total of 379 general practices and 3,057 persons with type 2 diabetes participate in the study (Denmark: 1,533 persons; UK Cambridge: 867 persons; UK Leichester: 159 persons; and the Netherlands: 498 persons). The general practitioners were randomised to either routine care or intensive care. The routine care group followed the national guidelines for diabetes treatment. The intensive care group was educated to provide intensive multi-factorial treatment according to the treatment algorithm developed for the study.

Follow-up at 5 and 10 years

Primary endpoint data were available for 3055 (99·9%) of the screen-detected participants. The mean duration of follow-up was 5.3 years. The improvements  in cardiovascular risk factors (HbA1c and cholesterol concentrations and blood pressure) were slightly, but significantly, better in the intensive treatment group. The incidence of first cardiovascular event was 7.2% (13.5 per 1000 person-years) in the intensive treatment group and 8.5% (15.9 per 1000 person-years) in the routine care group (HR: 0.83, 95% CI: 0.65–1.05). All-cause mortality was 6.2% (11.6 per 1000 person-years) and 6·7% (12.5 per 1000 person-years; 0.91, 0.69–1.21). The ten-year follow-up of the ADDITION study is currently taking place, and results will soon be presented.