Healthcare organization mergers: a systematic review of the literature on clinical outcomes

Background: A wave of healthcare organization mergers have been pursued for more than two decades in different countries regardless the type of health systems, although little attention is paid to their impact and assessment. The objective of this work is to synthesize evidence on the effect on clinical outcomes of patients after a merger of a healthcare organization, through a systematic review of the literature Methods: This systematic review was conducted according to the Population-Intervention-Comparison-Outcome model, using specific keywords and Boolean operators to build a search string, and by querying 3 electronic databases. Articles that reported quantitative evaluation of the impact of mergers on clinical outcomes were included. Titles, abstracts, and data extraction performed by 2 independent investigators Results: From a total of 28748, 5 studies met our inclusion criteria and 37 indicators were identified: 54.1% didn’t show any variation, 32.4% worsened and only 13.5% improved significantly after the merger. In particular, orthopedic care didn’t show any statistically significant variation in 44.5% indicators, while 33.3% showed a worsening and 22.2% an improvement in clinical outcomes. Obstetrics and neonatal indicators care didn’t change in 50.0% and 33.3% of them showed a statistically significant worsening. Cardiovascular disease indicators showed that acute myocardial infarction mortality didn’t variate in 75.0% of the indicators but 25.0% worsened. Indicators of heart failure, percutaneous coronary intervention and coronary artery bypass graft mortality didn’t improve significantly. Eventually, 60.0% of stroke mortality indicators showed a significant worsening. Conclusions: The impact of mergers showed contrasting effect on health outcomes that should be considered when these activities are intended to be pursued. These processes should be followed by a periodic assessment and actions that try to continuously improve and reach the targeted results Key messages: Mergers may imply important consequences in terms of clinical outcomes that should not be underestimated. A continuous evaluation approach to health risks linked to this type of intervention is suggested.