About one third of Australians with gout will cease their urate-lowering therapy (ULT) within the first month of treatment and about two-thirds within the first year, according to Australian PBS data on dispensing patterns.
The study of prescriptions of ULT and colchicine between April 2014 and December 2019 found allopurinol was the overwhelming choice for ULT (98.4%).
The monthly average number of allopurinol scripts for the 10% sample of the PBS was 10,828. Most people who purchased a script were males, over 60 years and concessional card holders.
The study found the 300mg dose accounted for 68.3% of all allopurinol scripts and the 100 mg dose in the 200 pack size accounted for 25.1% while increasing as a proportion of all scripts after September 2017.
The 100 pack size of 100 mg allopurinol only only accounted for 5% of scripts purchased and was discontinued in November 2018.
The study, published in the British Journal of Clinical Pharmacology, found the largest drop in persistence occurred immediately after initiation – with 34% of patients discontinuing the allopurinol 300 mg therapy in the first month.
“By 6 months 54% discontinued, by 12 months 63% discontinued, and by 24 months 72% had discontinued,” it said.
“This steep decline in persistence highlights that a large proportion of gout patients who are prescribed allopurinol are not receiving consistent long-term treatment.”
Similarly for the 100 mg dose, the largest reduction in persistence occurred in the first month, with 34% of patients discontinuing therapy.
“By 6 months 45% had discontinued, by 12 months 57% had discontinued, and by 24 months 67% had discontinued.”
“The asymptomatic nature of gout between gout flares is a contributing factor to the discontinuation of allopurinol,” the study said.
“We can assume that gout patients who have not experienced a gout flare for some time may consider ULT unnecessary and therefore decide to stop taking allopurinol. Comprehensive national initiatives which improve health literacy of people with gout are required to improve persistence to allopurinol.”
Joint first author on the paper Professor Ric Day told the limbic that pockets of higher ethnic risk warranted special attention as individuals with affected family and community members could perceive their condition as inevitable and not worth managing.
For example, a recent Australian study confirmed the known higher risk of gout in Maori and Pacific Islanders reflected in ED presentations and hospital admissions in Western Sydney.
The study said culturally-appropriate interventions to address gout management including medication adherence were urgently required.
Professor Day, from St Vincent’s Hospital Sydney, said fear of adverse events,“overdoing” the ULT, or being “resistant” to allopurinol were other reasons for treatment discontinuation.
“We’ve learnt in fact that [adverse events] was an overrated risk and that a lot of people kept the dose too low because of fear that they may cause the problem especially if the kidneys weren’t operating at full capacity.
“We’ve learnt you can dose to whatever dose you need to get the urate levels down to target.”
He added that the low rate (6.8%) of colchicine prophylaxis during initiation of allopurinol was unexpected as well as the fact that there was no increase in persistence for those who were co-prescribed colchicine.