Diabetes prevalence, process of care and outcomes in relation to practice size, caseload and deprivation: national cross-sectional study in primary care

Objective To examine the association between practice list size, deprivation and the quality of care of patients with diabetes. Design Population-based cross-sectional study using Quality and Outcomes Framework data. Setting England and Scotland. Participants 55 522 778 patients and 8970 general practices with 1852 762 people with diabetes. Interventions None. Main outcome measures Seventeen process and surrogate outcome measures of diabetes care. Results The prevalence of diabetes was 3.3%. Prevalence differed with practice list size and deprivation: smaller and more deprived practices had a higher mean prevalence than larger and more affluent practices (3.8% versus 2.8%). Practices with large patient list sizes had the highest quality of care scores, even after stratifying for deprivation. However, with the exception of retinal screening, peripheral pulses and neuropathy testing, differences in achievement between small and large practices were modest (< 5%). Small practices performed nearly as well as the largest practices in achievement of intermediate outcome targets for HbA1c, blood pressure and cholesterol (smallest versus largest practices: 57.4% versus 58.7%; 70.7% versus 70.7%; and 69.5% versus 72.7%, respectively). Deprivation had a negative effect on the achieved scores and this was more pronounced for smaller practices. Conclusion Our study provides some evidence of a volume-outcome association in the management of diabetes in primary care; this appears most pronounced in deprived areas.