Promoting population health with public-private partnerships: Where's the evidence?

Although public-private partnerships have become common in the health sector, the evidence supporting their effectiveness is limited, and when the products or services provided by the private partner are harmful to health inherent conflicts of interest may be difficult to overcome. The objective of this study is to appraise the evidence describing process or effectiveness of public-private partnerships (PPPs) that aim to promote population health, and analyse how characteristics such as independence or competing interests influence the results of their evaluation. We carried out a systematic search of Medline and Web of Science to identify scientific reports evaluating the process or effectiveness of PPPs that aim to promote population health. Two reviewers applied inclusion criteria, extracted and evaluated study quality. We classified PPPs according to the health problem tackled, the independence of the evaluation, and the potential for competition between business interests of the private partner and health promotion activity undertaken. We classified the conclusions of the evaluation as positive (supportive/tentatively supportive) or negative (semi-critical/critical). We identified 36 studies evaluating 25 PPPs. Evaluations that were favourable to the use of PPPs in health promotion were more frequently classed as "not independent" and of poor quality. On the other hand, negative evaluations were more common when the PPP involved a private partner with a high potential for competition between the health promotion activity undertaken and their financial interests. PPPs that sought to prevent non-communicable diseases were more frequently negatively evaluated compared to PPPs tackling infectious disease or other types of health problem. Almost all of the evaluations evaluated process, with only 2 papers reporting quantitative health related outcomes. There is still a lack of sound evidence supporting the effectiveness of public-private partnerships in health promotion, and the evidence base is skewed by non-independent evaluations. Public health actors should abstain from engaging in agreements with industries whose business interests have a high potential for competition with the health promotion activity undertaken.