Persistence with urate-lowering therapy in Australia: A longitudinal analysis of allopurinol prescriptions.

ABSTRACT

AIM: Gout is the most common form of inflammatory arthritis in men. Despite the availability of effective urate-lowering therapies (ULT), the management of gout is suboptimal due to poor persistence with ULT. This study examined national prescribing patterns of ULT to determine persistence with allopurinol in Australia. METHODS: A 10% sample of the Australian Pharmaceutical Benefits Scheme dispensing claims database was used to identify individuals initiated on allopurinol between April 2014 and December 2019. The number of allopurinol scripts dispensed was used to estimate persistence with allopurinol. Persistence was defined as the number of months from initiation until discontinuation (last prescription with no further scripts acquired for a period thereafter). Kaplan-Meier curves were used to examine persistence, while Cox regression analysis was used to examine the influence of gender, concomitant colchicine and age. RESULTS: The largest drop in persistence occurred immediately after initiation, with 34% of patients discontinuing allopurinol 300-mg therapy in the first month. Median persistence with allopurinol 300 mg was 5 months (95% confidence interval 4.76-5.24), with around 63% of individuals not persisting with this therapy for more than 12 months. Concomitant prescription of colchicine on the day of allopurinol initiation only occurred in 7% of allopurinol initiations. No increase in persistence was observed for those co-prescribed colchicine. CONCLUSION: Persistence with allopurinol was poor. More effective methods targeting prescribers, patients and systems are required to promote persistence with allopurinol. Improving persistence to allopurinol is an important public health goal given the proven potential of this medication to eliminate gout.