Who attends a UK diabetes screening programme? Findings from the ADDITION-Cambridge study.

AIMS: One of the factors influencing the cost-effectiveness of population screening for Type 2 diabetes may be uptake. We examined attendance and practice- and individual-level factors influencing uptake at each stage of a diabetes screening programme in general practice. METHODS: A stepwise screening programme was undertaken among 135, 825 people aged 40-69 years without known diabetes in 49 general practices in East England. The programme included a score based on routinely available data (age, sex, body mass index and prescribed medication) to identify those at high risk, who were offered random capillary blood glucose (RBG) and glycosylated haemoglobin tests. Those screening positive were offered fasting capillary blood glucose (FBG) and confirmatory oral glucose tolerance tests (OGTT). RESULTS: There were 33 539 high-risk individuals invited for a RBG screening test; 24 654 (74%) attended. Ninety-four per cent attended the follow-up FBG test and 82% the diagnostic OGTT. Seventy per cent of individuals completed the screening programme. Practices with higher general practitioner staff complements and those located in more deprived areas had lower uptake for RBG and FBG tests. Male sex and a higher body mass index were associated with lower attendance for RBG testing. Older age, prescription of antihypertensive medication and a higher risk score were associated with higher attendance for FBG and RBG tests. CONCLUSIONS: High attendance rates can be achieved by targeted stepwise screening of individuals assessed as high risk by data routinely available in general practice. Different strategies may be required to increase initial attendance, ensure completion of the screening programme, and reduce the risk that screening increases health inequalities.

How much might cardiovascular disease risk be reduced by intensive therapy in people with screen-detected diabetes?

AIMS: To assess the cardiovascular disease (CVD) risk of people with screen-detected Type 2 diabetes and to estimate the risk reduction achievable through early intensive pharmacological intervention. METHODS: In ADDITION-Cambridge, diabetic patients were identified among people aged 40-69 years through a stepwise screening procedure including a risk score, random and fasting capillary blood glucose, HbA(1c) and oral glucose tolerance test. In those without prior macrovascular disease, 10-year CVD risk was computed using UK Prospective Diabetes Study (UKPDS) and Framingham engines. The absolute risk reduction achievable and its plausible range were predicted using relative risk reductions for individual therapies from published trials and sensitivity analysis. RESULTS: Of the 867 individuals with undiagnosed diabetes, 19% had pre-existing CVD, 97% were overweight or obese, 86% had hypertension, 75% had dyslipidaemia, 20% had microalbuminuria and 18% were smokers. Of those with hypertension, 35% were not prescribed drugs and 42% were suboptimally treated. Of participants with dyslipidaemia, 68% were not prescribed medications and 22% were poorly controlled. Median 10-year CVD risk was 34.0%[interquartile range (IQR) 26.2-44.6] in men and 21.5% (IQR 15.7-28.7) in women using the UKPDS engine; 38.6% (IQR 27.8-53.0) in men and 24.6% (IQR 17.2-32.9) in women using Framingham equations. In the most conservative scenario (no additive effect of therapies), the absolute risk reduction achievable through multifactorial therapy ranged from 4.9 to 9.5% (UKPDS) and from 5.4 to 10.5% (Framingham). The corresponding ranges of numbers needed to treat were 11-20 and 10-19. CONCLUSIONS: People with screen-detected diabetes have an adverse cardiovascular risk profile, which is potentially modifiable through application of existing treatment recommendations.