Mergers of primary care organizations: a systematic review of the literature

Background Mergers as large-scale collaborations in primary care organizations have become a commonplace in developed countries to offer economies of scale and more efficient delivery of care to population. The aim of this systematic review is to summarize the scientific evidence on the relationship between the increase in the size of organizations providing primary care services and their performance. Methods The PICO model was adopted and three electronic databases (Medline, Scopus, ISI Web of Knowledge) were searched using appropriate keywords. Screening by title and abstract and data extraction were performed by two independent investigators. Articles, written in English, evaluating the performance after increasing the size of an organization were included. Selected articles were assessed for quality and risk of bias using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Process and outcome quality indicators were used for evaluation. Results From a total of 1337, 12 studies met the inclusion criteria and 103 indicators were identified: 59.2% did not show any variation, 33.9% improved significantly after the merger, 6.9% worsened after the merger. In particular, diabetes care did not show any statistically significant variation in 40.0 % of the indicators, while 10.0 % showed an improvement and 10.0% a worsening in clinical outcomes. A significant negative association was found between practice list size and reported non-urgent or urgent doctors’ availability (P < 0.05, both). The process of merging also created perceptions of takeover and had a negative effect on staff. Conclusions The effects of mergers are conflicting and there is little evidence that the performance is associated with the size of the structures involved. Assessment on the impact of primary care mergers should to be related to the population needs and the context where these processes are carried out