Statins and Risk of Rheumatoid Arthritis: A Nested Case-Control Study.

Objective: Statins have antiinflammatory/immunomodulatory effects that may be useful in preventing rheumatoid arthritis (RA), but previous observational studies about the risk of RA with statin use yielded conflicting results. The aim of this study was to determine whether high-intensity statin treatment is associated with reduced risk of RA.

Methods: Using data from the UK Clinical Practice Research Datalink, we performed a nested case-control analysis in a population-based cohort of patients who began receiving statins between 1997 and 2009 and were followed up until a first diagnosis of RA, death, end of registration with the physician's practice, or end of January 2011. For each case of RA, 10 age-, sex-, and calendar year-matched controls were randomly selected from risk sets. We estimated the hazard ratio (HR) of incident RA in the highest quintile of duration-weighted average statin intensity compared to the lowest, using conditional logistic regression. Models were adjusted for smoking status, total cholesterol level, obesity, history of cardiovascular disease, coexistent autoimmune disease, hypothyroidism, and persistence with treatment.

Results: The cohort included 528,654 new users of statins, with 1,357 new cases of RA occurring during a mean follow-up of 3.3 years, for an incidence rate of 7.9 per 10,000 person-years. Cases were more likely to be smokers, to have other autoimmune diseases, and to have had lower total cholesterol levels at baseline. The incidence of RA was lower in the highest statin intensity quintile (adjusted HR 0.77 [95% confidence interval 0.63-0.95]) in comparison to the lowest quintile.

Conclusion: In this large population-based study, high-intensity statin treatment was associated with a reduced risk of RA in comparison to low-intensity statin treatment.