Studies With Direct Industry Affiliation Are More Likely to Report Positive Results in Randomized Controlled Trials for Platelet-Rich Plasma Use in Rotator Cuff Tears: A Systematic Review.

Abstract

To perform a systematic review to evaluate the effect of industry affiliation on the outcomes of randomized controlled trials for platelet-rich plasma (PRP) injections in rotator cuff tears METHODS: The PubMed, SPORTDiscus, and Scopus databases were searched from 2010 to the present for the terms "rotator cuff" and "platelet-rich plasma." The inclusion criteria were randomized controlled trials comparing PRP with controls for the treatment of rotator cuff tears, and the exclusion criteria were systematic reviews, meta-analyses, case reports, cohort studies, basic science studies, studies of Level III or below, and studies not in English. Degree of industry affiliation was categorized into 3 groups: directly, indirectly, and not affiliated. Direct affiliation required the study or its authors to receive financial support from the company manufacturing the devices used in the study to prepare or administer PRP. Indirect affiliation required financial association with a different company that produces or administers PRP than the company in the study. Studies were classified as favorable if study outcomes achieved significance (P < .05) of PRP over controls or as analogous if there was no statistical significance between PRP and controls. Data were analyzed using the χ² test and Fisher exact test. Of the 47 studies selected for analysis, 8 (17.0%) had no direct industry affiliation; 9 (19.1%) had indirect affiliation; and 30 (63.8%) had no industry affiliation. Of the studies, 22 (46.8%) reported favorable results with PRP compared with controls and 25 (53.2%) showed analogous results between PRP and controls. Degree of industry affiliation was significantly associated with an increased likelihood of reporting favorable study outcomes (P = .041). Directly affiliated studies had a significantly increased likelihood of reporting favorable results (P = .024) compared with indirectly affiliated studies. Studies that used PRP produced by companies that directly funded the studies or were financially affiliated with the authors were significantly more likely to report favorable results. Level II, systematic review of Level I and II studies.