Effect of statin use on the risk of rheumatoid arthritis: A systematic review and meta-analysis

Objectives: Anti-inflammatory and immune-modulating effects of statins suggest that they may play a role in the risk of rheumatoid arthritis (RA). We aimed to perform a systematic review and meta-analysis of studies assessing the risk of RA in statin-users versus non-users. Methods: We searched Medline from inception to 01/22/2019 and Embase from 1988 to Week 03 2019 for studies that examined the association between statin use and RA without restrictions on language. Results: We identified 1,161 references; of them 8 studies (5 cohort studies and 3 case-control studies) were included in the systematic review. Four cohort studies comparing statin-users versus non-users were included in the meta-analysis. The pooled risk ratio (RR) was 1.01; 95%CI 0.93–1.10; I² = 17%. Case-control studies showed highly heterogeneous results (I² = 92%) and were not included in the meta-analysis. One cohort study and one case-control study assessing persistence with or intensity of treatment with statins showed lower risk of RA with higher versus lower treatment persistence or intensity of statin use (pooled RR 0.66; 95%CI 0.5–0.87; I² = 83%). The certainty in the evidence was low. Conclusion: In this systematic review and meta-analysis, we observed no difference in risk of RA in statin users vs non-users. Risk of RA may be lower in patients with higher versus lower statin treatment persistence or intensity. Future observational studies with guards against selection bias and confounding are needed to further elucidate the impact of statin use on the risk of RA, considering potential differences by dosage, duration of use, study population and other factors.