Original articleTraditional cardiovascular risk factors in rheumatoid arthritis: A meta-analysis
Introduction
Rheumatoid arthritis (RA) is associated with an increased risk for cardiovascular (CV) disease such as myocardial infarction, stroke and cardiac heart failure [1]. In large retrospective cohort studies of RA patients, the relative risk (RR) for myocardial infarction adjusted for CV risk factors showed a two- to three-fold increase, and the RR for stroke was 1.5 compared with control groups [1]. Compared with controls, RA patients have twice the risk of developing cardiac heart failure [2]. Finally, RA patients have a higher prevalence of preclinical atherosclerosis. For instance, asymptomatic carotid atherosclerotic plaques were reported more frequently in RA patients than in controls [3].
As expected, CV morbidity excess confers higher CV mortality. In a recent meta-analysis, Meune et al. calculated the standardized mortality ratios (SMRs) of CV mortality by pooling data of 17 studies (for a total of 91,916 patients). The overall pooled SMR was 1.6 (95% CI 1.5, 1.8) [4]. This increased risk of CV disease observed in RA might result from an interaction between traditional and non-traditional risk factors, both modulated by chronic inflammation. Among traditional risk factors, most of the studies show an increased prevalence of smoking in RA [1], [5], [6], [7], while the prevalence of hypertension [1], [3], [7], [8], diabetes mellitus [1], [7], [9] and dyslipidemia [10], [11], [12] is still a matter of debate.
Some less traditional CV risk factors, such as endothelial dysfunction, or paradoxical CV risk factors, such as low body mass index, were reported in RA [13], [14]. Furthermore, epidemiological data suggest that the inflammatory condition independently increases CV disease in RA even after adjustment on traditional CV risk factors. Del Rincon et al. compared the 1-year occurrence of CV-related hospitalizations and CV deaths in 236 RA patients and 4635 controls included in epidemiologic studies of atherosclerosis and CV disease. After adjusting for CV risk factors, the RR (95% CI) for incident CV events in RA patients was 3.17 (1.33-6.36) [15].
In the present study, we performed a systematic review of the literature and a meta-analysis to look for differences in the prevalence of traditional CV risk factor between RA patients and controls.
Section snippets
Methods
We followed standard guidelines for this meta-analysis. We identified all published studies that evaluated the prevalence of major CV risk factors in patients with RA by conducting a search of Medline from 1950 through December 2008 using the following combination of index terms: “smoking” or “hypertension” or “diabetes mellitus” or “lipoproteins” or “dyslipidemias” and “arthritis, rheumatoid”.
Studies were selected by two of us: we independently reviewed abstracts and made a first selection of
Results
Our initial search yielded 903 potential literature citations (Fig. 1). Three hundred and forty-three trials were automatically rejected when limiting the research to “age more than 19” and “humans”. Five hundred and fifteen articles were excluded after title and abstract screening because there was no control group, or because CV risk factors were not characterized according to the pre-specified criteria. The inter-observer agreement for the study selection was satisfactory (kappa = 0.94).
In the
Discussion
The results of our meta-analysis show that some traditional CV risk factors, such as smoking, diabetes mellitus or lower HDL cholesterol levels, are more prevalent in RA patients, while others, such as hypertension or hypercholesterolemia, appear to be similar to controls. However, significant heterogeneity among studies was found for diabetes mellitus and HDL cholesterol levels.
Our meta-analysis shows that smoking is more prevalent in RA. Smoking has been shown to increase the risk for
Conflict of interest statement
None of the authors has any conflicts of interest to declare.
Acknowledgments
This study was conducted with methodological support of the INSERM U558 unit.
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