Background Given their lipid-lowering and anti-inflammatory properties, statins may have dual cardioprotective [1] and anti-rheumatic benefits [2] in rheumatoid arthritis (RA). These effects are expected to confer survival benefits in RA patients, at least similar to those observed in the JUPITER trial [1] among otherwise healthy individuals with low LDL-cholesterol but with elevated hsCRP (i.e., a 20% reduction in overall mortality). However, no relevant data are available in the field.

Objectives To address this knowledge gap, we evaluated the impact of statin initiation on the risk of mortality among RA patients in a general population context.

Methods We conducted an incident user cohort study with time-stratified propensity score matching in a UK general population database. Our primary definition of RA required an RA diagnostic code with at least one use of a DMARD [3]. We compared statin initiators and non-initiators among patients with a new diagnosis of RA between January 2000 and December 2012. The outcome of interest was all-cause mortality. To closely account for confounding by indication and potential calendar-time effects, we employed propensity score-matched cohorts of statin initiators and non-initiators within 1-year cohort accrual blocks. Propensity scores (i.e., the predicted probability of statin initiation) were estimated using 50 variables, including RA duration, demographics, socio-economic status, body mass index, lifestyle factors, comorbidities, medication use, and healthcare utilization. We used Cox proportional hazard models to calculate hazard ratios for mortality.

Results Of 2,943 statin initiators, 432 died during the follow up period (mean=4.51 years), whereas among 2,943 matched non-initiators, 513 died during the follow up period (mean = 4.29 years) (Table 1). This corresponds to incidence rates of 32.6/1000 person-years (PY) and 40.6/1000 PY in the statin initiator and comparator groups, respectively. The baseline characteristics were well-balanced in the two groups. Statin initiation was associated with a 21% reduction in all-cause mortality (HR 0.79, 95% CI 0.68-0.91) (Figure 1a). When we defined RA by its diagnosis code alone (not requiring DMARD use), the corresponding HR was 0.81 (95% CI 0.74-0.90). When we compared the unmatched cohorts to examine the effectiveness of our propensity score matching, the statin initiators (n=3,438) actually showed a 46% higher risk of mortality (HR 1.46, 95% CI 1.28-1.67) than non-initiators (n=3,438) due to confounding by indication (Figure 1b).

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Conclusions Findings from this general population study indicate that statin initiation is associated with a survival benefit among RA patients, and its magnitude is similar to that shown in the JUPITER trial among non-RA patients [1].

References

1. The New England Journal of Medicine. 2008. 359(21):2195-2207.

2. Lancet. 2004. 363(9426):2015-2021.

3. Arthritis and Rheumatism. 2008. 59(9):1314-1321.

Disclosure of Interest None declared