The Dynamics of Chronic Gout Treatment: Medication Gaps and Return to Therapy

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 (