The effect of screening on the prevalence of diagnosed type 2 diabetes in primary care.

OBJECTIVE To investigate to what extent differences in diagnosed diabetes prevalence can be attributed to differences in the general practitioner's (GP) screening activity. DESIGN An analysis of electronic patient files in combination with a survey among GPs. Setting. Ten primary healthcare centres with 44 GPs in the Netherlands. PATIENTS General population (n = 58,919) and type 2 diabetic patients (n = 2582). MAIN OUTCOME MEASURES Each GP filled in a questionnaire with questions concerning screening methods for diabetes. The presence of diabetes and date of diagnosis were determined. The potential confounding variables age, sex, and postal code (which we used to determine socioeconomic status) were retrieved from patient records. RESULTS The yearly point prevalence of diabetes increased significantly from 2.92% in 2000-2001 to 4.25% in 2005-2006 (p = 0.002). The incidence increased from 3.29/1000 person-years to 5.13/1000 person-years (p = 0.019). High screening activity of the general practitioner resulted in statistically significantly higher odds (1.35; p = 0.015) of being diagnosed as a patient with diabetes. The effect was independent of the influence of age, gender, and socioeconomic status. CONCLUSION Screening activity of the GP has a statistically significant and relevant influence on the prevalence of diagnosed diabetes. General practitioners should evaluate their screening activity to optimize the identification of diabetic patients.