To examine the association between the use of statins and the risk of systemic lupus erythematosus (SLE) with focus on describing the patterns of risks over time.Setting
A population-based cohort study using the UK Clinical Practice Research Datalink.Participants
All patients aged 40 years or older who had at least one prescription of statins during the period 1995–2009 were selected and matched by age, sex, practice and date of first prescription to non-users. The follow-up period of statin users was divided into periods of current, recent and past exposure, with patients moving among these three exposure categories over time. Current statin users were also stratified into ≤1 year or >1 year of use.Main outcome measures
Time-dependent Cox models were used to calculate HRs of SLE, adjusted for disease history and previous drug exposure.Results
We included 1 039 694 patients, of whom 519 847 were statin users. Current statin users did not have an increased risk of developing SLE among patients aged ≥40 years (HRadjusted 0.75, 95% CI 0.53 to 1.07). Current statin users who continued the therapy for >1 year had a 38% lower risk of developing SLE (HRadjusted 0.62, 95% CI 0.42 to 0.93). When more specific definitions for SLE were used, this latter finding, however, was not observed.Conclusions
Our findings showed no effect of statins on the risk of developing SLE among patients aged ≥40 years. Further research is needed to study the long-term effects of statins on SLE.