Compliance with Allopurinol Therapy Among Managed Care Enrollees with Gout: A Retrospective Analysis of Administrative Claims

AYLIN A. RIEDEL, MICHAEL NELSON, NANCY JOSEPH-RIDGE, KATRINE WALLACE, PATRICIA MacDONALD, and MICHAEL BECKER

ABSTRACT.

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. (J Rheumatol 2004;31:1575-81)

Key Indexing Terms:

GOUT
ALLOPURINOL
PATIENT COMPLIANCE
RETROSPECTIVE STUDIES
MANAGED CARE PROGRAMS

---

From Ingenix Pharmaceutical Services, Eden Prairie, Minnesota, and TAP Pharmaceutical Products Inc., Lake Forest, Illinois, USA.

Supported by TAP Pharmaceutical Products, Inc. Dr. Becker provides consulting services to TAP Pharmaceutical Products, Inc.

A.A. Riedel, PhD; M.A. Nelson, PharmD, Ingenix Pharmaceutical Services; N. Joseph-Ridge, MD; P. MacDonald, NP, TAP Pharmaceutical Products Inc.; K.L. Wallace, MA, TAP Pharmaceutical Products, Inc. and University of Illinois at Chicago School of Public Health, Chicago, IL; M.A. Becker, MD, University of Chicago, Chicago, IL.

Address reprint requests to Dr. A.A. Riedel, Research and Data Solutions Group, Ingenix, Inc., 12125 Technology Drive, MN002–0258, Eden Prairie, MN 55344.

Submitted October 24, 2003; revision accepted February 4, 2004.

---