The impact of primary care supply on quality of care in England

Many countries use regulation or financial incentives to try and increase the supply of general practitioners (GPs) to areas perceived as underserved. Such policies rest on the premise that increasing the supply of primary care will improve the access to health services, the quality of care received, and in turn the health of the individuals in the area. Although the premise is plausible, its evidence base is rather weak. Studies to date on the link between primary care supply and health, which have mainly used state-level data from the USA, suggest that increased supply of primary care improves health, but little is known as to how this effect is achieved. The aim of this study is to assess the relationship between primary care supply and the quality of primary care in England. We use data from the English Longitudinal Study of Aging (ELSA) which provides a panel of individuals aged 50 and over living in England. Wave 2 to 4 (2004 to 2009) include data on a number of indicators developed for assessing the quality of care of the consultations. The survey data are linked to Primary Care Trusts (PCT) level data on primary care supply measured by the number of GPs in the area of residence and the average distance to the general practice. We use multilevel and longitudinal data modelling regression analysis to investigate the impact of GP supply on quality of care after controlling for individual and area covariates. We analyse 35 indicators of quality of care covering 13 medical conditions. In the pooled analysis across all 35 indicators, our findings suggest that, after controlling for individual demographic characteristics, socioeconomic factors, perceived health, and area level factors, a larger number of GPs in the area has a statistically significant and positive impact on quality of care, and distance from GP practice has a statistically significant and negative impact. These impacts were concentrated in indicators of care related to cardiovascular diseases and arthritis, and on specific indicators for diabetes, incontinence and hearing problems. This study identifies a link between supply of primary care and the quality of services provided in England, and thus provides evidence for one mechanism by which primary care supply might affect health. Furthermore, our findings are of interest in a health system where increasing emphasis is placed on quality improvement and where the evolving role of GPs as commissioners in the NHS in England might restrict their contact time with patients, effectively reducing the supply of GPs.