In our sample of systematic reviews focusing on treatments for glaucoma, reviews conducted by authors with a conflict of interest were more likely to reach favorable conclusions compared with reviews without conflicted authors.
Previous studies have demonstrated that authors’ conflict of interest can influence outcomes of systematic reviews. Therefore, we aimed to determine whether the presence of 1 of more conflicts was associated with more favorable results and conclusions in systematic reviews of glaucoma interventions.
Materials and Methods:
MEDLINE and Embase were searched for systematic reviews of glaucoma treatments published between September 1, 2016 and June 2, 2020. Author conflicts of interest were located using multiple databases (eg, CMS Open Payments Database, Dollars for Profs, Google Patents, the United States Patent and Trademark Office USPTO) and previously published disclosure statements. Study sponsorship was determined using each review’s funding disclosure statement.
Our study included 26 systematic reviews conducted by 108 authors. Of these reviews, 9 (35%) were conducted by at least 1 author with an undisclosed conflict of interest. Of those 9, 3 (33%) reported results favoring the treatment group, and 5 (56%) reported conclusions favoring the treatment group. Of the 17 systematic reviews with no conflicted authors, 1 (6%) reported results favoring the treatment group, and 2 (12%) reported conclusions favoring the treatment group. The Fisher exact tests demonstrated that these differences held a statistically significant association between author conflicts and the favorability of the reviews’ conclusions toward the treatment group (P=0.04).
We found that systematic reviews conducted by 1 or more authors with conflicts of interest were more likely than those with no conflicted authors to draw favorable conclusions about the investigated intervention.