Adherence and treat to target benchmarks in older adults with gout initiating urate lowering therapy in Ontario, Canada: a population-based study

Objectives — We sought to evaluate urate lowering therapy (ULT) adherence and treatment-to-target (T2T) serum uric acid (SUA) levels amongst older adults with gout starting ULT.

Methods — We performed a population-based retrospective cohort study in Ontario, Canada in patients with gout aged ≥66 years newly dispensed ULT between 2010 and 2019. We defined successful T2T as patients having SUA levels <360 μmol/L (6 mg/dL) within 12-months after ULT dispensation. We also assessed adherence to ULT. Multi-level logistic regression clustered by ULT prescriber evaluated patient, physician and prescription factors associated with reaching target SUA levels.

Results — Among 44,438 patients (mean (SD) age 76.0±7.3 years; 64.4% male), 30,057 (67.6%) patients had ≥1 SUA test completed. Overall, 52.3% patients reached SUA target within 12-months, improving from 45.2% in 2010 to 61.2% in 2019 (p < 0.0001). ULT adherence was 55.3% overall and improved annually. Key factors associated with achieving T2T included febuxostat use (OR 11.40, 95% CI 5.10-25.43) (was only dispensed in 88 patients), ULT adherence (OR 5.17, 95% CI 4.89-5.47) allopurinol starting doses >50 mg (OR 2.53, 95% CI: 2.14-2.99), colchicine/oral corticosteroids co-prescription (OR 1.24, 95% CI: 1.14-1.34) and ULT prescription from a rheumatologist.

Conclusions — Only 52.3% of patients achieved an optimal SUA level within 1 year of ULT initiation. ULT adherence was suboptimal though improving over time. ULT adherence and higher allopurinol starting doses had the strongest associations of achieving a target SUA level. This study highlights room for improvement in gout management and potential strategies to address care gaps.