To assess the policy proposed by the American Diabetes Association of universal screening in general practice of all patients aged over 45 years for diabetes.
Cross sectional population study.
Local general practice in the United Kingdom.
All patients aged over 45 not known to have diabetes.
Main outcome measures
Prevalence of diabetes in the screened population, cardiovascular risk profile of patients diagnosed as having diabetes after screening.
Of 2481 patients aged over 45 and not known to have diabetes, 876 attended for screening. There were no significant demographic differences between the screened and unscreened patients. Prevalence of diabetes in patients with age as a sole risk factor was 0.2% (95% confidence interval 0% to 1.4%). Prevalence of diabetes in patients with age and one or more other risk factors (hypertension, obesity, or a family history of diabetes) was 2.8% (1.6% to 4.7%). Four hours a week for a year would be needed to screen all people over 45 in the practice's population; about half this time would be needed to screen patients with risk factors other than age. More than 80% of patients newly diagnosed as having diabetes had a 10 year risk of coronary heart disease >15%, 73% (45% to 92%) were hypertensive, and 73% (45% to 92%) had a cholesterol concentration >5 mmol/l.
Screening for diabetes in general practice by measuring fasting blood glucose is feasible but has a very low yield in patients whose sole risk factor for diabetes is age over 45. Screening in a low risk population would best be targeted at patients with multiple risk factors.
What is already known on this topic
Between a third and a half of cases of diabetes are undiagnosed at any one time
New cases can be identified by screening groups of patients at risk
The American Diabetes Association has proposed the screening of all patients aged over 45 every three years
What this study adds
Screening for diabetes in general practice by measuring fasting blood glucose is feasible but requires much staff time
Screening solely on the basis of age has a very low yield and screening would best be targeted at patients with multiple risk factors for diabetes