Background/Purpose:

Given their lipid-lowering and anti-inflammatory properties, statins may
have dual cardioprotective and anti-rheumatic benefits in psoriasis or
psoriatic arthritis. These effects may confer survival benefits in this
particular patient population, at least similar to those observed in the JUPITER
trial 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. To address this knowledge gap, we
evaluated the impact of statin initiation on the risk of mortality among
patients with psoriasis or psoriatic arthritis in a general population context.

Methods:

We conducted an incident user cohort study with time-stratified propensity
score matching in a United Kingdom general population database. We compared
all-cause mortality between statin initiators and non-initiators among patients
with a new diagnosis of psoriasis or psoriatic arthritis (n=36,228) between
January 2000 and December 2012. 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 disease
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
18,114 statin initiators, 1831 died during the follow up period (mean=4.64
years), whereas among 18,114 matched non-initiators, 2374 died during the
follow up period (mean=4.37 years). This corresponds to incidence rates of
21.8/1000 person-years (PY) and 29.9/1000 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 30%
reduction in all-cause mortality (HR 0.70, 95% CI 0.66-0.75) (Figure 1a).
When we compared the unmatched cohorts to examine the effectiveness of our
propensity score matching, the statin initiators (n=20,120) actually showed a
49% higher risk of mortality (HR 1.49, 95% CI 1.39-1.59) than non-initiators
(n=20,120 randomly selected, without propensity score matching) due to
confounding by indication (Figure 1b).

Conclusion:

Findings
from this general population study indicate that statin initiation is
associated with a survival benefit among patients with psoriasis or psoriatic
arthritis, and its magnitude appears larger than that shown in the JUPITER
trial.