Change in serum urate level with urate-lowering therapy initiation associates in the immediate term with patient-reported outcomes in people with gout

Abstract

ObjectiveTo examine the associations of changes in serum urate (SU) with health-related quality of life (HRQOL) in gout. MethodsWe used the first 6-months of data from four interventional trials and one observational, open-label study of urate-lowering therapy (ULT) use. HRQOL were assessed at baseline and every 3-months, and SU was measured monthly. Primary outcome measures were Short-form 36 physical and mental component summary scores, Health Assessment Questionnaire Disability Index (HAQ-DI), Sheehan Disability Scale (SDS), Patient Global Assessment, and pain scores in the last week. Linear mixed models for each outcome were adjusted as appropriate for current SU, change in urate in the last month, number of flare-affected days in the last month, baseline BMI, age, comorbidities, sex, ethnicity, trial/study and treatment combination, and tophi status (fixed effects); subject, and the trial/study month were random effects. ResultsHigher current SU correlated with reduced physical and mental HRQOL, and increased SDS and pain but not with HAQ-DI score. In the first 6-months of new/escalating ULT use, absolute change in SU levels associated with poorer outcomes on the HAQ-DI scale (β (95% CI) = 0.013 (0.007–0.019)) and poorer outcomes on SDS, SF-36 MCS, patient global and pain scales. Reduction of SU associated with poorer outcomes in all six measures. ConclusionHigh SU levels were associated with poorer HRQOL, pain and Sheehan disability score. Recent SU level fluctuations are associated with poorer outcomes, primarily driven by a reduction in SU. Clinical emphasis on slow rather than fast SU reduction and the routine use of effective, anti-inflammatory medications at ULT initiation/escalation may avoid short-term poor outcomes.