Compliance with allopurinol therapy among managed care enrollees with gout: a retrospective analysis of administrative claims.

OBJECTIVE: Poor compliance with gout medications has been recognized, but seldom studied. We investigated compliance with allopurinol among managed care enrollees suspected to have gout.
METHODS: This was a retrospective, administrative claims-based analysis of patients with gout. Compliance with allopurinol was measured using prescription-fill dates and days-supplied amounts. Compliance was defined for each prescription period as the presumed use of allopurinol on at least 80% of the days of that period.
RESULTS: Of 9482 patients identified, 65.9% filled at least one prescription for allopurinol during the 24 month followup period; 10.4% of allopurinol users filled one prescription and then discontinued use. Of the remaining patients, 13.7% never achieved compliance with therapy; 18% were compliant throughout the entire followup period. Patients were compliant with therapy for an average of 56% of their treatment periods and noncompliant for an average of 44%. In multivariate analysis, male sex was associated with decreased compliance (p < 0.01), although the effect was mitigated by increasing age. For subjects of both sexes, increasing age was associated with increased compliance (p < 0.05).
CONCLUSION: Compliance with allopurinol in this population was low. Because untreated gouty arthritis can lead to serious adverse outcomes (such as recurrent gouty arthritis, chronic gouty arthropathy, tophi, and urolithiasis) that are usually avoidable with antihyperuricemic therapy, efforts to achieve better compliance are warranted.