Evaluation of allopurinol use in patients with gout

Abstract

The use of long-term allopurinol therapy in patients with gout was evaluated. A pharmacy computer printout was used to identify all outpatients for whom allopurinol had been prescribed during a six-month period in 1985 at a large Veterans Administration medical center. Medical records were reviewed to (1) classify patients as either having or not having definite indications for allopurinol treatment, (2) determine whether physicians had ordered roentgenographic and laboratory tests for presence of monosodium urate crystals, uric acid excretion, and renal function, and (3) identify gout-associated risk factors and disease entities that could cause hyperuricemia. A pharmacy record of all allopurinol and probenecid prescriptions for the six-month period was obtained, along with cost data. Of the 286 patients who received allopurinol, 32 received the drug for an indication that could not definitely be established as gout. Of the 254 remaining patients, only 45 (17.7%) had a definite indication for allopurinol use as defined by the pharmacy and therapeutics committee. Although pretreatment measurement of serum creatinine was common, only a few patients underwent joint aspiration, a 24-hour urine collection, or roentgenography of affected joints. Large proportions of the patients were found to have gout-associated risk factors. If the 209 patients without definite indications for allopurinol therapy had been treated with probenecid instead of allopurinol, the annual cost savings would have been about $3700. Most of the patients receiving allopurinol for gout could reasonably have been treated with a uricosuric agent such as probenecid at a lower cost. Generally, physicians did not use diagnostic tests optimally before prescribing allopurinol and did not attempt to modify risk factors for gout.