Duration and dose of allopurinol needed to attain the serum urate target in gout

Objective: To examine, in patients with gout using escalating urate-lowering therapy (ULT), the treatment duration and allopurinol dose required to attain the serum urate (SU) target (< 360 μmol/L; < 6 mg/dL). Method: We studied patients in the NOR-Gout prospective cohort with a recent gout flare and increased SU (> 360 μmol/L). Patients escalated allopurinol dosage until reaching the SU treatment target of <360 µmol/L, switching, if needed, to febuxostat. Results: Of 211 patients, 95.2% were male; mean ± sd age was 56.7 ± 13.7 years, disease duration 8.1 years, 16.6% had clinical tophi, and 12.8% used allopurinol at cohort entry. Mean SU (μmol/L) was reduced from 500 at baseline to 312 at 1 year and 325 at 2 years. Target SU was attained at least once during year 1 by 197 patients (93.4%). Median time to attaining the treatment target was 2 months (mean 2.9 months), and median allopurinol dose was 200 mg (mean 243 mg). Eighty per cent of patients reached the treatment target by 3 months. Patients with SU >480 μmol/L at baseline needed a median of 3 months to attain target SU versus 2 months for patients with SU <480 μmol/L (log-rank p < 0.001). A switch to febuxostat was seen in 12.4% at year 1 and 15.1% at year 2. Conclusion: Treat-to-target ULT using allopurinol leads to attainment of the SU target within 2–3 months at low doses for most patients. Very few patients did not achieve the treatment target at least once during year 1. Trial registration: ACTRN12618001372279.