The association of Raynaud's syndrome with rheumatoid arthritis--a meta-analysis.

Rheumatoid arthritis (RA) has traditionally been included among the diseases associated with Raynaud's syndrome (RS). The prevalence of RS in patients with RA is not well defined. The objective of this paper was to assess the prevalence of RS in patients with RA-a meta-analysis of published data was performed. The PubMed database of the National Library of Medicine and ISI Web of Knowledge was used for studies dealing with RS and RA. The studies provided sufficient data to estimate the prevalence of RS in patients with RA. A forest plot was determined by the revealed prevalences. Statistical analysis was based on methods for a random effects meta-analysis and a finite mixture model for proportions. Publication bias was investigated with the linear regression test (Egger's method). A meta-regression was conducted by the year of publication. Twenty-eight eligible studies, contributing data on 3,730 subjects, were included in this meta-analysis. For RA, a pooled prevalence of 12.3% and 95% CI = 0.093-0.157 were obtained. A mixture model analysis found five latent classes. Statistically and graphically, publication bias was present (p = 0.031). In the meta-regression, the estimated prevalence decreased within the observation period (1977-2010) from 11.2% to 9.4%. Despite some heterogeneity, there is a possible indication of an association for RS and patients with RA.