Background/Purpose: Currently, there are no guidelines in the United States on monitoring serum uric acid (sUA) levels in gout and gout treatment patterns. However, there are guidelines from the European League Against Rheumatism gout task force and the British Society for Rheumatology/British Health Professionals in Rheumatology. Our aim was to assess treatment patterns for gout and laboratory sUA monitoring in a managed care population in the U.S., relative to international guidelines.

Methods: Data were extracted from the HealthCore Integrated Research Database (HIRD^SM), which contains integrated medical and pharmacy claims and laboratory result data from a large commercial U.S. health insurer. Eligible patients had either ≥2 medical claims for gout (ICD-9-CM code = 274) or ≥1 pharmacy claim for gout medications (allopurinol, colchicine, febuxostat, probenecid, sulphinpyrazone) between 01/01/2008 and 05/31/2011. The date of the earliest relevant claim was set as the index date. We included patients ≥18 years of age on index date, with ≥12 months of continuous eligibility pre-index date. Key guidelines selected in this study included initiating dose of allopurinol, mean time to dose escalation, maximum dosing levels, and sUA lab testing. We focused on a subgroup of patients initiating urate-lowering therapies (ULTs) after a new gout diagnosis (no pre-existing gout at baseline). Additionally, for a subset of patients with available electronic laboratory data, sUA levels were assessed within a year prior to and after initiation of ULTs. Treatment patterns were assessed until end of eligibility or end of the study period using descriptive statistics.

Results: We identified 93,546 eligible patients; 26% (n=24,555) were female and 35% (n=32,729) initiated ULTs. Mean (± SD) age was 58±14.83 years and Charlson Comorbidity Index score was 1.35± 2.02. Allopurinol accounted for 96% (n=31,388) of all first-line ULT fills, followed by probenecid (n=1,032) and febuxostat (n=309). No patients initiated sulphinpyrazone. Compared to guidelines, the mean starting dose of allopurinol was higher (213±114.48 mg/day vs. 100mg) and mean time to dose escalation was longer (24±28.6 weeks vs. 2-4 weeks); however, maximum daily dosing levels (244±117.12 mg/day) were within the recommended range. While 61% (n=19,843) of patients who initiated ULT had ≥1 sUA test prior to ULT initiation, only 34% (n=11,256) had ≥1 sUA test pre- and post-ULT initiation. Among 10,926 patients with sUA levels above target range (sUA >6 mg/dL) prior to ULT initiation, only 11% (n=1,190) achieved the goal of sUA ≤6mg/dL within a year of ULT initiation.

Conclusion: Comparing the results of this study to international guidelines shows room for improvement, specifically in laboratory monitoring of sUA levels relative to gout treatment. The results may be due in part to lack of U.S. guidelines regarding the appropriate frequency of sUA testing relative to starting ULT, dose adjustment, and achievement of target sUA levels.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/treatment-patterns-and-monitoring-of-serum-uric-acid-levels-in-a-large-cohort-of-gout-patients-in-the-united-states-is-there-room-for-improvement/