A meta-research study finds unclear impact of institutional conflicts of interest on conclusions of studies investigating volume-outcome relationships.

Abstract

Objective: This study aimed to explore institutional conflicts of interest (COIs) in volume-outcome studies investigating whether higher hospital volume is associated with better patient outcomes.

Study design and setting: We used a sample of studies (n=68) included in a systematic review on the hospital volume-outcome relationship in total knee arthroplasty. For studies in which at least one of the study authors was affiliated with a hospital, we contacted the study authors by email to obtain their institutional volume and to survey them about their opinion on institutional COIs. We categorized the studies' conclusions (positive vs. non-positive) and authors' hospital volume (high, intermediate, low). We compared conclusions for high vs. intermediate/low hospital volume categories RESULTS: Of 29 hospital-affiliated authors contacted, 20 replied. Authors from high-volume institutions were more likely to conclude that a hospital volume-outcome relationship existed compared to authors from intermediate- or low-volume institutions, although this was not statistically significant (odds ratio, OR: 2.0; 95% confidence interval, CI: 0.21; 18.7). Six out of 17 authors (35%) believed that institutional factors such as the case volume were (very) likely to influence the study design, analysis, or conclusions of research in the field of volume-outcome studies; 4/17 (24%) were neutral; and 7/17 (41%) believed that this was (very) unlikely.

Conclusion: This is the first study explicitly investigating institutional financial interests with benefit through increasing services provided by the institution. The findings suggest the possibility that institutional COI may influence the conclusions of volume-outcome studies, although the results are inconclusive. Surveyed authors had divergent opinions on whether institutional factors are likely to influence research integrity. Further research is needed to investigate institutional COIs.