Background/Purpose:

Guidelines for initiating urate lowering therapy (ULT) in the treatment of gout recommend treatment to a target serum urate (SUA) level of ≤6mg/dl with monitoring of SUA.

Methods:

We reviewed the use of ULT with allopurinol (allop) or febuxostat (febux) in a large health care system between June 2010 and April 2012. Eligible subjects were >18 years at ULT initiation, had a diagnosis of gout, and had ≥ two outpatient prescriptions for a ULT after June 1, 2010. Demographics, ULT dose, prescribing providers, diagnosis, and SUA levels were collected from our EPIC EMR using Explorys Inc. proprietary software. A study author checked agreement of data between the subjects EMR and the Explorys data in random cases within the study population. Cleveland Clinic IRB approval was obtained.

Results:

1,870 subjects were eligible for inclusion: 74.1% male, mean age 62.8 (SD 14.2). Study subjects had been prescribed allop alone (82.5%, n=1543), febux alone (5.9%, n=188), or both (11.6%, n=217). Following initiation of ULT, 68.8% of subjects (n=1286) had a repeat SUA within our health system: 56.1% within 6 months and 65.4% within 12 months of their initial prescription. After initiation of ULT, 45.9% of subjects achieved a level of ≤6mg/dl, 22.0% had levels between 6.1-7.0mg/dl, and 32.1% never had a level ≤7.0mg/dl. There were 523 subjects on allop with SUA measurements ≥7.0mg/dl, yet only 2.3% were prescribed a daily dose of >300mg. Subjects treated by a rheumatologist (60.6%) vs non-rheumatologist (42.0%) were more likely to achieve a SUA ≤6mg/dl, odds ratio 2.1 (95% CI 1.7-2.7). The starting dose of allop was <100mg (1.0%), 100mg (59.6%), 101-300mg (38.8%). For subjects prescribed allop the maximum daily dose was ≤ 100mg in 32.4% and 101-300mg in 65.0% of subjects. Maximum dose of allop was greater than 300mg in 2.7% of subjects seen by a rheumatologist and 2.6% of non-rheumatologists. The starting dose of febux was ≤ 40mg in 87.9% of subjects. Of those who did not achieve a SUA level ≤6.0mg/dl, 38.4% had ULT adjusted to a higher dose (ULT adjustment to target may not have been completed by the time of analysis). Only 11.3% of subjects started on febux had documented allop intolerance. A statistically significant difference was found in the mean creatinine level closest to the initiation of ULT (1.3 allop vs 1.5 febux p<0.001) which may indicate renal insufficiency as a perceived reason for febuxostat.

Conclusion:

Only 45.9% of patients started on ULT achieved recommended SUA levels, only 38.4% of those not meeting target had a documented dose adjustment and > 97% of patients on allop were on < 300mg per day. This demonstrates a persistent care gap in the treatment of gouty arthritis.