The dynamics of chronic gout treatment: medication gaps and return to therapy

Leslie R. Harrold, University of Massachusetts Medical School
Susan E. Andrade, University of Massachusetts Medical School
Becky A. Briesacher, University of Massachusetts Medical School
Marsha A. Raebel, Kaiser Permanente
Hassan Fouayzi, University of Massachusetts Medical School
Robert A. Yood, University of Massachusetts Medical School
Ira S. Ockene, University of Massachusetts Medical School

Abstract

OBJECTIVE: To identify gaps in therapy with urate-lowering drugs for the treatment of gout as well as factors associated with resuming therapy.

METHODS: From 2 integrated delivery systems, we identified patients 18 years or older with a diagnosis of gout who initiated use of a urate-lowering drug from January 1, 2000 through June 30, 2006 and who had a gap in therapy. A gap was defined as a period of over 60 days after the completion of 1 prescription in which no refill for a urate-lowering drug was obtained. Survival curves were used to assess return to therapy of urate-lowering drugs. Cox proportional hazards analysis estimated the association between covariates and return to therapy.

RESULTS: There were 4166 new users of urate-lowering drugs (97% received allopurinol), of whom 2929 (70%) had a gap in therapy. Among those with a gap, in 75% it occurred in the first year of therapy. Fifty percent of patients with a gap returned to therapy within 8 months, and by 4 years it was 75%. Age 45-74 years (<45 >referent) and greater duration of urate-lowering drug use before the gap was associated with resuming treatment within 1 year. In contrast, receipt of nonsteroidal anti-inflammatory drugs or glucocorticoids in the year before the gap was associated with a reduced likelihood of resuming therapy.

CONCLUSIONS: The majority of gout patients with gaps in urate-lowering drug use returned to treatment. More investigation is needed to better understand why patients may go for months without refilling prescriptions, given the clinical consequences of nonadherence.