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

Abstract

Purpose: To perform a systematic review to evaluate the effect of industry affiliation on the outcomes of randomized controlled trials (RCTs) for platelet-rich plasma (PRP) injections in rotator cuff tears.

Methods: PubMed, SPORTdiscus, and Scopus databases were searched from 2010 to the present for terms "rotator cuff" and "platelet-rich plasma." Inclusion criteria were RCTs comparing PRP to controls for treatment of rotator cuff tears and exclusion criteria were systematic reviews, meta-analyses, case reports, cohort studies, basic science studies, other level 3 and below studies, and studies not in English. Degree of industry affiliation was categorized into three groups: direct, indirect, 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 one used in the study. Studies were classified as favorable if study outcomes achieved significance (p < 0.05) of PRP over the control, or analogous if there was no statistical significance between PRP and control. Data was analyzed using chi-squared and fisher's exact tests.

Results: Of the 47 studies selected for analysis, 8 (17.0%) had no direct industry affiliation, 9 (19.1%) indirect affiliation and 30 (63.8%) no industry affiliation. 22 (46.8%) studies reported favorable results with PRP compared to the control and 25 (53.2%) showed analogous results between PRP and control. Degree of industry affiliation was significantly associated with increased likelihood of reporting favorable study outcomes (p = 0.041). Directly affiliated studies had a significantly increased likelihood of reporting favorable results (p = 0.024) compared to indirectly affiliated.

Conclusions: Studies that used PRP produced by companies that directly fund the study or were financially affiliated with the authors were significantly more likely to report favorable results.

Level of evidence: Systematic review of Level I and II studies.