Background/Purpose: Randomized controlled trials (RCTs) are considered the gold standard for assessment of healthcare interventions. Recently, there have been growing concerns about the quality of reporting of results in RCTs. Factors such as pharmaceutical industry sponsorship and financial conflicts of interest among authors are may create bias and influence study quality. No studies have addressed these issues in fibromyalgia RCTs. Our objective was to assess the quality of reporting in drug therapy randomized controlled trials (RCTs) of fibromyalgia and their effect on study outcome.

Methods: MEDLINE and Cochrane Central Register of Controlled Trials databases were searched to identify original fibromyalgia drug therapy RCTs published between 1997 and 2011. Eligible studies were identified by screening the title and abstract for original, randomized, parallel design drug trials with clinical primary outcome(s). Two reviewers independently assessed each RCT for study characteristics, outcome [positive (statistically significant result favoring experimental drug for the primary outcome) or not positive], and quality measures (sample size calculation, adequacy of randomization, allocation concealment, double-blinding, follow-up description, and intention-to-treat (ITT) analysis). RCTs with and without different types of quality measures were compared using Chi-square, Fisher’s exact or likelihood ratio test. 

Results: 47 eligible RCTs were identified. In 21 (44.6%) RCT’s, random sequence generation and allocation concealment were described adequately. Statistical power calculation was reported in 28 (62.2%) RCTs (2 RCTs were excluded as they were phase 2 studies). Double-blinding was reported in 21 (44.6%) of trials. In 30 (63.8%) RCTs, ITT analysis and prospectively defined follow-up schedule were also described. There were no significant assocations between specific quality measures and study outcome (Table).

Conclusion: Study quality measures are not consistently reported in fibromyalgia drug therapy RCTs. The presence of specific types of study quality measures in RCTs was not associated with higher likelihood of positive study outcome.

Table. Association of positive study outcome with types of study quality measures.

Study Quality Measure	Quality measure present n/N (%)	Quality measure absent n/N (%)	p-value
Sample Size Calculation	20/28 (71.4%)	14/17 (71.4%)	0.493
Randomization	18/21 (85.7%)	17/26 (65.4%)	0.179
Allocation concealment	16/20 (80.0%)	19/27 (70.4%)	0.517
Double-blinding	14/21 (66.7%)	21/26 (80.8%)	0.326
Description of follow-up	23/30 (76.7%)	12/17 (70.6%)	0.733
Intention-to-treat analysis	24/30 (80.0%)	11/17 (64.7%)	0.306

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/quality-of-reporting-in-pharmacological-randomized-controlled-trials-for-fibromyalgia/