OBJECTIVE: To determine whether Cochrane Musculoskeletal Group (CMSG) systematic reviews and corresponding primary studies of rheumatoid arthritis interventions report and analyze the data needed to assess the effectiveness of interventions in reducing socioeconomic differences in health and/or improving the health of the poor. METHODS: We selected all CMSG reviews on rheumatoid arthritis published since issue 1, 2003. Fourteen reviews were identified; 147 of the 156 primary studies included in these reviews were obtained and assessed. We extracted data on whether the dimensions place of residence, race/ethnicity/culture, occupation, gender, religion, education, socioeconomic status, and social capital and networks (PROGRESS) were reported or analyzed, and whether any interventions were aimed at disadvantaged or low- and middle-income country populations. RESULTS: Among the dimensions of PROGRESS reported at baseline in 147 primary studies, gender (89%) was the most commonly reported, followed by education (25%) and race/ethnicity (18%). Less than 50% of the systematic reviews reported dimensions of PROGRESS even when they had been reported in the primary study. Of 147 primary studies, 6 (5%) were aimed specifically at disadvantaged populations; another 6 reported on effectiveness by at least 1 dimension of PROGRESS. CONCLUSION: Primary studies of interventions for rheumatoid arthritis generally reported few variables necessary to answer questions about health inequalities. Most CMSG systematic reviews failed to assess those variables even when described in the primary studies. The Cochrane Health Equity Field welcomes the opportunity to provide guidance to systematic review authors on incorporating equity considerations into their reviews.