Risk of rheumatoid arthritis diagnosis in statin users in a large nationwide US study

Objective To evaluate the association between statin use and the risk of developing rheumatoid arthritis (RA) in a large, US case-control study. Methods Using the OptumLabs Data Warehouse, RA cases were identified as patients aged [greater than or equai to]18 years with [greater than or equai to]2 RA diagnoses between January 1, 2010 and June 30, 2019 and [greater than or equai to]1 prescription fills for methotrexate within 1 year of the first RA diagnosis. The first RA diagnosis was the index date. Cases were matched 1:1 to controls on age, sex, region, year of index date, and length of baseline coverage. Statin users were defined by having [greater than or equai to]2 statin prescription fills at least 90 days pre-index. Patients identified as statin users were further classified by statin user status (current or former), statin use duration, and intensity of statin exposure. Odds ratios for RA risk with statin use were estimated using logistic regression. Results 16,363 RA cases and 16,363 matched controls were identified. Among RA cases, 5509 (33.7%) patients were statin users compared to 5164 (31.6%) of the controls. Statin users had a slightly increased risk of RA compared to non-users (OR 1.12, 95% CI 1.06-1.18), and former statin users had an increased RA risk compared to current users (OR 1.21, 95% CI 1.13-1.28). However, risk was eliminated following adjustment for hyperlipidemia. The risk estimates for statin use duration and intensity did not reach significance. Conclusion This study demonstrates no significant increase in the risk of developing RA for statin users compared to non-users after adjustment for hyperlipidemia in addition to other relevant confounders. However, more information from prospective studies would be necessary to further understand this relationship. Keywords: Rheumatoid arthritis, Lipid-lowering medications, Risk factors