High risk of clinical cardiovascular events in rheumatoid arthritis: Levels of associations of myocardial infarction and stroke through a systematic review and meta-analysis.

While there are convergent data suggesting that overall cardiovascular mortality is increased in patients with rheumatoid arthritis, the relative contributions of myocardial infarction and stroke remain unclear. We sought to clarify this issue by conducting a meta-analysis of cohort studies on myocardial infarction and stroke in patients with rheumatoid arthritis. A MEDLINE search from January 1960 to September 2009 and abstracts from international conferences from 2007 to 2009 were searched for relevant literature. All cohort studies reporting on standardized mortality ratio or incidence rate ratio of myocardial or stroke associated with rheumatoid arthritis, with available crude numbers, were included. STATA meta-analysis software was used to calculate pooled risk estimates. Seventeen papers fulfilled the inclusion criteria, corresponding to a total of 124,894 patients. Ten studies reported on standardized mortality ratio for fatal myocardial infarction, which ranged from 0.99 to 3.82. The overall pooled estimate was 1.77 (95% confidence interval [CI] 1.65-1.89). Incidence rate ratio for myocardial infarction was reported in five studies; the pooled estimate was 2.10 (95% CI 1.52-2.89). Nine studies reported on fatal stroke, with standardized mortality ratio ranging from 1.08 to 2.00; the pooled estimate was 1.46 (95% CI 1.31-1.63). The pooled incidence rate ratio for stroke (three studies) was 1.91 (95% CI 1.73-2.12). Our results show that risks of myocardial infarction and stroke are increased in patients with rheumatoid arthritis. In addition, both account for the observed increased mortality in individuals with rheumatoid arthritis.