Evaluating the impact of capitation funding top-up payments in primary care

Background Capitation payments account for approximately half of core funding for General Practitioner (GP) practices in England, allocated via the Global Sum Allocation (‘Carr-Hill’) formula. The formula has not been updated since 2004 and lacks adjustments for clinical diagnoses, patient communication difficulties, and deprivation which are factors known to influence workload and health outcomes. In July 2021, Leicester, Leicestershire, and Rutland (LLR) Integrated Care Board introduced the Health Equity Payment (HEP), a top-up funding scheme based on a locally developed formula incorporating these additional factors. Method: We conducted a retrospective observational study using national public data to evaluate the impact of HEP between July 2021 and April 2023. Practices receiving HEP were matched to similar practices outside LLR using Genetic Matching on demographics, disease prevalence, and baseline outcomes. Seven outcomes were assessed: three patient experience measures from the GP Patient Survey, three staffing metrics (GP, nurse, and administrative full-time equivalents per 1000 weighted patients), and Quality and Outcomes Framework (QOF) achievement. Causal effects were estimated using doubly robust regression models with g-computation to estimate the average treatment effect. Results: Sixty-two LLR practices received HEP and were matched to 62 control practices. Practices receiving HEP achieved a 3.2 percentage point higher QOF score (95% CI: 0.5 to 5.9; p = 0.02) compared to controls. No statistically significant differences were found in patient experience or staffing outcomes. Sensitivity analyses confirmed robustness to alternative time periods and outcome specifications but revealed sensitivity to missing staffing data from atypical practices. Discussion: This study provides the first causal evaluation of a capitation funding model incorporating clinical and sociodemographic factors in England. The modest improvement in QOF achievement suggests that targeted funding could be linked to enhanced care quality. The absence of effects on staffing and patient experience may reflect data limitations, short follow-up, or heterogeneity in how funds were used. These findings provide the the first evidence that locally tailored funding models could address inequalities in primary care provision and inform ongoing national reviews of the general practice capitation funding.