Influences on the variation in prevalence of type 2 diabetes between general practices: practice, patient or socioeconomic factors?

backgroundThe prevalence of type 2 diabetes is known to vary between countries, districts and general practices. The influence of early detection and screening on the variation of prevalence between general practices has not previously been investigated.

aimTo test the hypothesis that the prevalence of type 2 diabetes is associated with awareness of and screening for diabetes within general practices and to explore other factors that may explain the variation in prevalence between practices. DESIGN OF STUDY: Cross-sectional study of general practices.

settingForty-two general practices in Newcastle and North Tyneside; 20% random sample of patients with type 2 diabetes (n = 1056).

methodFactors thought to be associated with the variation of type 2 diabetes prevalence were collected from general practices through practice managers, medical records, and patient questionnaire. Pearson's correlation coefficient was used to quantify the association, and variables significant at the 5% level were entered into a multiple linear regression model.

resultsThere was a wide inter-practice variation in age/sex standardised type 2 diabetes prevalence (range = 0.69% to 2.73%; P < 0.001). There was no significant association between the prevalence of type 2 diabetes and the proportion of patients detected outside primary care or the proportion of patients detected through screening, accounting for only 2% and 3% of the variation in type 2 prevalence between practices, respectively. The mean Townsend deprivation score accounted for 42% of the variation in type 2 diabetes prevalence between practices, with more deprived practices having a higher prevalence.

conclusionThis study suggests that socieconomic deprivation, rather than detection through screening or awareness of diabetes, accounts for much of the variation in prevalence of type 2 diabetes between practices.