Objective: To assess the association of industry funding with the characteristics, outcome and reported quality of randomised controlled trials (RCTs) of drug therapy for rheumatoid arthritis (RA).

Methods: MEDLINE and Cochrane Central Register of Controlled Trials databases were searched to identify original RA drug therapy RCTs published in 2002-03 and 2006-07.  Two reviewers independently assessed each RCT for the funding source, characteristics, outcome (positive (statistically significant result favouring experimental drug for the primary outcome) or not positive) and reporting of methodological measures whose inadequate performance may bias treatment effect assessment.  RCTs registered at ClinicalTrials.gov and completed in the study years were assessed for publication bias.

Results: 103 eligible RCTs were identified with following funding sources: 58 (56.3%) industry; 19 (18.4%) non-profit; 6 (5.8%) mixed; and 20 (19.4%) unspecified.  Industry funded RCTs had significantly more study centres and subjects; while non-profit funded RCTs had longer duration, and were more likely to study different treatment strategies.  Outcome could be assessed for 86 (83.5%) RCTs.  Funding source was not associated with higher likelihood of positive outcomes favouring the sponsored experimental drug (industry (75.5%), non-profit (68.8%), mixed (40%) and unspecified (81.2%); p = 0.37).  Industry funded RCTs had a trend towards higher likelihood of non-publication (38.6% vs 16.7%, p = 0.093).  Industry-funded RCTs reported more frequent performance of double-blinding, adequate participant flow description and intention-to-treat analysis.

Conclusions: Industry funding was not associated with higher likelihood of positive outcomes of published drug therapy RCTs for RA, and reported better on some key RCT quality measures.