Adherence to guidelines and the Screening Tool of Older Persons' potentially inappropriate Prescriptions criteria for colchicine dosing for gout treatment in beneficiaries of the Nova Scotia Seniors' Pharmacare Program

Introduction: Colchicine is a drug commonly used to prevent and treat gout however, older persons have higher risks of adverse effects. Longer durations of colchicine use > 3 months is potentially inappropriate in older persons. Recent evidence also suggests lower dosing of colchicine is as effective and results in fewer adverse effects as compared to higher colchicine dosing. The objectives of this study were to determine the dose and duration of colchicine and to evaluate adherence to international guidelines and recommendations for colchicine use in older persons. Methods: A retrospective, observational study was completed from April 1, 2006 to March 31st, 2011 to evaluate colchicine use. Patients enrolled in the Nova Scotia Seniors' Pharmacare Program who had gout and who filled at least one prescription for colchicine during the study period were included. Colchicine dose and duration were reported. Findings: A total of 518 individuals were dispensed 1327 courses of colchicine during the study period. The average daily dose of colchicine ranged from 1.39mg to 1.50mg. Inappropriate doses of colchicine > 1.2mg were prescribed in approximately a third of the study population. Colchicine was prescribed for > 90 days in 14.2% of treatment courses and for > 180 days in 8.1% of treatment courses. Female sex was the only predictor of treatment duration > 90 days. Implications: This study is the first to report on colchicine dose and duration in a specific cohort of older persons with gout. Strategies to improve colchicine prescribing in older persons are needed.