Poor medication adherence has been demonstrated in patients with incident gout initiating allopurinol therapy, particularly in women, younger individuals, and patients with fewer comorbidities, according to a retrospective data analysis published in Rheumatology (Oxford). Medication adherence also remained low even in individuals who reinitiate treatment after a gap in therapy.
The investigators conducted an analysis using data from the UK Clinical Practice Datalink between 1987 and 2014 to examine non-persistence and non-adherence to the urate-lowering therapy (ULT) allopurinol in patients with newly diagnosed gout and to identify the factors linked to poor medication adherence. A total of 48,280 patients ≥40 years with incident gout who began allopurinol treatment were evaluated. Kaplan-Meier statistics were used to estimate the percentage of patients who were non-persistent, defined as a first medication gap of ≥90 days after 1 and 5 years, along with the median time until an initial 90-day gap. Non-adherence, defined as the percentage of days covered <80%, over the full observation period was also calculated.
The presence of non-persistence increased from 38.5% after 1 year of allopurinol initiation (95% CI, 38.1-38.9) to 56.9% after 5 years of allopurinol initiation (95% CI, 56.4-57.4). The median time until an initial 90-day gap was 1029 days (95% CI, 988-1078), with 61% of participants considered non-adherent. Although 43.3% of patients restarted treatment within 1 year after an initial gap (95% CI, 42.7-43.9), only 52.3% persisted with the treatment for 1 year (95% CI, 51.4-53.1).
Female gender and current smoking status increased the risk for non-adherence and non-persistence, whereas older age; being overweight; receiving antihypertensive medication or colchicine; and having dementia, diabetes, or dyslipidemia all decreased that risk.
The investigators concluded that adherence to allopurinol in patients with incident gout who restart treatment after a medication gap remains low. These findings highlight the need for research on medication adherence to ULT in patients with gout. Target groups for adherence interventions should include patients at higher risk.
Scheepers LEJM, Burden AM, Arts ICW, et al. Medication adherence among gout patients initiated allopurinol: a retrospective cohort study in the Clinical Practice Research Datalink (CPRD) [published online June 8, 2018]. Rheumatology (Oxford). doi:10.1093/rheumatology/key155