The Public Health Impact score: a new measure of public health effectiveness for general practices in England.

BACKGROUND Health policy in the UK is increasingly focused on the measurement of outcomes rather than structures and processes of health care. AIM To develop a measure of the effectiveness of primary care in terms of population health outcomes. DESIGN AND SETTING A cross-sectional study of general practices in England. METHOD Twenty clinical quality of care indicators for which there was evidence of mortality reduction were identified from the national Quality and Outcomes Framework (QOF) pay-for-performance scheme. The number of lives saved by 8136 English practices (97.97% of all practices) in 2009/2010 was estimated, based on their performance on these measures, and a public health impact measure, the PHI score, was constructed. Multilevel regression models were used to identify practice and population predictors of PHI scores. RESULTS The mean estimated PHI score was 258.9 (standard deviation [SD] = 73.3) lives saved per 100 000 registered patients, per annum. This represents 75.7% of the maximum potential PHI score of 340.9 (SD = 91.8). PHI and QOF scores were weakly correlated (Pearson r = 0.28). The most powerful predictors of PHI score were the prevalence of the relevant clinical conditions (β = 0.77) and the proportion of patients aged ≥65 years (β = 0.22). General practices that were less successful at achieving their maximum potential PHI score were those with a lower prevalence of relevant conditions (β = 0.29), larger list sizes (β = -0.16), greater area deprivation (β = -0.15), and a larger proportion of patients aged ≥65 years (β = -0.13). CONCLUSION The PHI score is a potential alternative metric of practice performance, measuring the estimated mortality reduction in the registered population. Rewards under the QOF pay-for-performance scheme are not closely aligned to the public health impact of practices.