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Among patients with gout and diabetes, allopurinol nonpersistence and interruptions in treatment are common and are linked to more prescriptions for prednisone, according to results of a study published in Seminars in Arthritis and Rheumatism.
The researchers sought to characterize persistence, patterns of use, and predictors of allopurinol use in a population-based cohort of patients with gout and diabetes.
Administrative health care data from Ontario, Canada, between April 1, 2002, and March 31, 2009, were collected. The Ontario Drug Benefit was used to access data on prescription medication use, which was available for patients older than 65 years. The study cohort included patients with diabetes who had received a prescription for allopurinol after the age of 66 years, which was selected because prescription claims data are available in Ontario beginning at 65 years. The index date was the date of the first allopurinol prescription after age 66 years, with no allopurinol usage in the previous year.
All patients were followed-up until the earlier occurrence of death or 3 years from the date of the initial allopurinol prescription (ie, the index date). Outcomes evaluated in the study included allopurinol nonpersistence (ie, discontinuation of allopurinol at any time during the follow-up) and indicators of gout severity during follow-up (ie, prescriptions for prednisone or colchicine, hospitalization/emergency department visits for gout, and outpatient visits for gout).
Regarding patterns of usage, patients were divided into 3 groups: adherers (ie, allopurinol used continuously throughout the follow-up period); discontinuers (ie, nonpersistence with subsequent resumption); and interrupters (ie, nonpersistence with no subsequent resumption).
A total of 22,056 patients with diabetes (13,640 men) who filled a new prescription for allopurinol after age 66 years were followed-up for a maximum of 3.0 years (range in total cohort, 0.16-3.0 years). The median number of allopurinol prescriptions per patient was 12 (IQR, 7-15). The median prescription duration was 82.5 days (IQR, 45-94.2 days). The median daily allopurinol dose was 200 mg (IQR, 180-300 mg).
Overall, 58.8% (n=12,964) of the patients were persistent with allopurinol use during follow-up and received treatment with allopurinol continuously for 3.0 years (range, 62 days to 3.0 years). In 41.2% (n=9092) of the participants, nonpersistence with allopurinol was noted, with a median time to drug discontinuation of 0.36 years (IQR, 0.09-1.14 years).
Several variables were significantly associated with a higher risk for nonpersistence: female sex (hazard ratio [HR], 1.28; 95% CI, 1.23-1.33); dementia (HR, 1.23; 95% CI, 1.11-1.35); and an outpatient visit for gout in the previous year (HR, 1.19; 95% CI, 1.09-1.29).
Overall, a total of 12,964 patients with allopurinol adherence, 4618 with allopurinol interruption, and 4474 with allopurinol discontinuation were identified. Compared with the adherers, allopurinol interrupters and discontinuers had indicators of more severe gout over time, which included a higher likelihood of receiving a prescription for prednisone.
The researchers concluded that suboptimal allopurinol adherence may not only increase an individual’s risk for complications from gout, but may potentially enhance complications from diabetes because of the greater use of prednisone and its negative effects on glycemic control.
The added, “Additional studies are required understand the barriers to allopurinol use in individuals with [comorbid] diabetes, develop comprehensive strategies for optimizing adherence, and evaluate the relationships between allopurinol adherence and clinical gout and diabetes outcomes.”
Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.
Reference
Weisman A, Tomlinson GA, Lipscombe LL, Perkins BA, Hawker GA. Allopurinol adherence, persistence and patterns of use in individuals with diabetes and gout: a retrospective, population-based cohort analysis. Semin Arthritis Rheum. 2021;51(6):1162-1169. doi:10.1016/j.semarthrit.2021.09.003
