Subclinical atherosclerosis in patients with rheumatoid arthritis

Abstract

Objective To evaluate the prevalence of subclinical atherosclerosis in rheumatoid arthritis (RA) and the related risk factors. Methods Fifty RA patients without overt atherosclerotic disease and 121 control subjects matched for age and sex were recruited. Duplex carotid sonography was used to measure intimamedia thickness (IMT) and plaque formation assessment. Differences between RA and the control group were compared, and the risk factors were explored. RA patients then were divided into two subgroups according to IMT and the comparison between the two subgroups were completed. T test, Mann-Whitney U test, chi-square test, Pearson's correlation and Logistic regression analysis were used for statistical analysis. Results Although RA patients had lower level of serum lipids and body mass index than the control group, the mean IMT value was significantly higher in the RA group than that in the control group [(0.78±0.18) mm vs (0.62±0.14) mm, t=5.853, P=0.000], and plaque formation was more prevalent [56.0%(28/50) vs 36.4% (44/121), χ2=5.596, P=0.018]. The difference was especially significant in the younger groups (<50 years old group and 50-60 years old group). Logistic regression showed that the presence of RA [OR=7.34, 95%CI (2.53, 21.25)], male [OR=2.0, 95%CI (91.25, 3.17)] and old age [OR=1.1, 95%CI (1.04, 21.15)] were the independent risk factors for abnormal IMT (thickened or the presence of carotid plaques). The RA patients were divided into two subgroups according to IMT. Compared with patients with normal IMT, patients with abnormal IMT were older and more common in postmenopausal, and had longer RA duration and higher cholesterol level. In treatment, less patients with abnormal IMT had been taking methotrexate (MTX) for more than 3 months compared with patients with normal IMT. Among these parameters, old age [OR=1.13, 95%CI (1.03, 1.23)] was shown to be the independent risk factor for abnormal IMT in RA patients, and more than 3 months of MTX treatment [OR=0.12, 95% CI (0.02, 0.71)] was the protective factor. Conclusion Atherosclerosis occurs frequently and prematurely in patients with RA and the presence of RA is an independent risk factor for atherosclerosis. Early primary prevention for atherosclerosis should be recommended. MTX probably has a positive effect on preventing atherosclerosis for RA patients, which needs to be confirmed by further study. Key words: Arthritis, rheumatoid; Arteriosclerosis; Ultrasonography