Background/Purpose: Fibromyalgia randomized controlled trials (RCTs) have become more common in the past 15 years, in part due to industry sponsorship. Recently, there has been growing concern that financial conflicts of interest (FCOIs) among authors and funding source may affect reporting of results in RCTs. These issues have not yet been adressed for fibromyalgia RCTs. The objective of this study was to determine the prevalence of pharmaceutical industry funding and and FCOIs among authors of RCTs of drug therapy for fibromyalgia and assess their association with study outcome. 

Methods: MEDLINE and Cochrane Central Register of Controlled Trials databases were searched for fibromyalgia drug therapy RCTs published between 1997 and 2011. Eligible studies were original, randomized, parallel design drug trials with clinical efficacy as primary outcome. Two reviewers independently assessed each RCT for funding source (industry, non-profit, mixed), FCOI disclosure by author, and outcome [positive (statistically significant result favoring experimental drug for the primary outcome) or not positive]. RCTs with and without different types of FCOIs were compared using Chi-square, Fisher’s exact or likelihood ratio test.

Results: Of 47 eligible RCTs, study sponsors were industry (25, 53.2%), non-profit (9, 19.1%), mixed (5, 10.6%), and unspecified (8, 17%). A higher likelihood of positive outcomes was associated with industry sponsorship (22/25, 88%) and unspecified funding (6/8, 75%) compared to other funding types [non-profit 4/9 (44.4), mixed 3/5 (60%); P = 0.073]. Industry funded RCTs were significantly associated with positive outcome compared to non-profit funded RCTs (P = 0.017).  FCOIs among authors were reported in 30 (63.8%) RCTs. RCTs with author(s) employed by the industry sponsor or author(s) who received consultancy fee/honoraria from the industry sponsor had significantly higher likelihood of positive outcome (Table). All RCT’s (15/15) of the three Food and Drug Administration-approved drugs (duloxetine, pregabalin, and milnacipran) were industry sponsored and all had positive outcomes. Adjustment for potential confounding factors, such as type of experimental drug, study duration, and number of enrolled patients, could not be performed due to small number of eligible RCTs.

Conclusion: Industry sponsorship and FCOIs are common in published fibromyalgia drug therapy RCTs and are more likely to be associated with positive outcomes. The small number of eligible trials precluded adjustment for potential confounders to assess whether these represent independent association with study outcome.

Table. Association of positive study outcome with types of financial conflicts of interest.

Relationship to drug industry	FCOI present n/N (%)	FCOI absent n/N (%)	p-value
Any FCOI	25/29 (86.2)	10/18(55.6)	0.037
Employee status	19/19 (100)	16/28 (57.1)	0.001
Consultancy fees/honoraria	15/16 (93.8)	20/31(64.5)	0.037
Stock ownership	10 /11 (90.9)	25/36 (69.4)	0.244
Research grant	16/20(80)	19/27 (53.8)	0.517

n: Number of RCTs with positive outcome within each group

N: Total number of RCTs in each group

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/financial-conflicts-of-interest-and-industry-sponsorship-are-associated-with-positive-outcomes-in-fibromyalgia-randomized-controlled-trials/