A simple pragmatic system for detecting new cases of type 2 diabetes and impaired fasting glycaemia in primary care

Background: Although whole population screening for type 2 diabetes is not currently considered to be justified, targeted screening within higher risk groups may be more cost-effective, and more pragmatic. Objectives: Our aim was to investigate the feasibility and performance of a pragmatic system for identifying patients with type 2 diabetes and impaired fasting glycaemia (IFG). Methods: A clustered observational survey of the prevalence of diabetes and IFG was carried out in randomly selected patients from four at-risk groups. Patients were identified by computerized searching of practice databases for age and body mass index (BMI) risk criteria. Sixteen practices in South West England screened 1287 Caucasian patients from four groups with progressive levels of theoretical risk (age >70 and BMI ≥33, age >65 and BMI ≥31, age >60 and BMI ≥29, and age >50 and BMI ≥27). Fasting plasma glucose was measured and repeated if abnormal to determine the prevalence of new cases in each group. BMI and age data were validated against measures taken at the clinic. Results: The response rate was 60.6% and the prevalence of new cases of type 2 diabetes in each group was 4.7% [95% confidence interval (CI) 2.8–7.7], 5.7% (95% CI 4.0–8.2), 3.8% (95% CI 2.4–6.0) and 2.6% (95%CI 1.4–4.7), respectively. An additional 5.2–8.4% had IFG. Conclusions: Targeted screening by searching existing GP records for age and BMI criteria is feasible for use in general practice in the UK. Screening of patients with a BMI of ≥27 and aged >50 by fasting glucose identified a substantial prevalence of undetected type 2 diabetes and IFG. The relative costs and benefits as well as the pragmatic advantages of different systems need further evaluation.