Non-adherence to urate lowering therapy in gout after 5 years is related to poor outcomes: results from the NOR-Gout study.

Objectives: Patients with gout need to adhere to medication over time to achieve good outcomes. We assessed self-reported adherence to medication with urate lowering therapy (ULT) 5 years after a treat-to-target intervention and studied how non-adherence was related to baseline demographic and disease variables.

Methods: Patients in the NOR-Gout observational study were included after a recent gout flare and serum urate >360 µmol/l. Patients [mean age 56.2 (S.D. 13.6), 94.5% males, 17.2% with tophi] attended tight-control visits over one year with escalating urate lowering therapy using a treat-to-target strategy. Five-year follow-up included the Medication Adherence Report Scale (MARS-5) questionnaire (range 5-25) for adherence. Flares and SUA target achievement were compared for 5-year adherence to medication.

Results: At 5 years most of the 163 patients used ULT (95.1%). MARS-5 adherence scores after 5 years were high (median 24, interquartile range 22-25). Patients in the lowest MARS-5 quartile had, compared with the highest quartile, more often a flare during the last year of follow-up (33.3% vs 9.5%, P = 0.004) and reached the 5-yr serum urate treatment target less frequently (45.2% vs 87.5%, P < 0.001). Baseline lower age (OR 0.56, 95%CI 0.39-0.79), non-European origin (OR 0.22, 95%CI 0.06-0.80), lower SF-36 mental health scores (OR 0.94, 95%CI 0.91-0.98) and less joint pain during last flare (OR 0.73, 95%CI 0.58-0.92) were independent risk factors for non-adherence to medication.

Conclusions: Patients reported high adherence to medication after 5 years. Non-adherence was related to more flares and less urate target achievement. Younger age and non-European origin were associated with non-adherence.