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Persistence with cholinesterase inhibitor therapy in a population‐based cohort of patients with Alzheimer's disease
Author(s) -
Amuah Joseph E.,
Hogan David B.,
Eliasziw Misha,
Supina Alison,
Beck Patricia,
Downey Winanne,
Maxwell Colleen J.
Publication year - 2010
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.1946
Subject(s) - medicine , discontinuation , medical prescription , cohort , proportional hazards model , cohort study , retrospective cohort study , hazard ratio , population , demography , confidence interval , environmental health , pharmacology , sociology
Purpose To estimate the risk (and determinants) of discontinuing cholinesterase inhibitors (ChEIs) in a population‐based sample of Alzheimer's disease (AD) patients. Methods This is a retrospective cohort study based on linked de‐identified administrative health data from the province of Saskatchewan, Canada. The cohort included all AD patients receiving a ChEI prescription during the first year of provincial coverage (2000–2001). Persistence was defined as no gap of 60+ days between depletion and subsequent refill of a ChEI prescription. Kaplan‐Meier analysis was used to estimate the risk of discontinuation over 40 months. Cox regression with time‐varying covariates was used to assess risk factors for ChEI discontinuation. Results The sample included 1080 patients (64% female, average age 80 ± 7 years). Baseline mean (SD) Mini‐Mental State Examination (MMSE) and Functional Activities Questionnaire (FAQ) scores were 20.8 (4.4) and 17.5 (7.7), respectively. Over 40 months, 84% discontinued therapy. The 1‐year risk of discontinuation was 66.4% (95%CI 63.5–69.3%). Discontinuation was significantly more likely for females (adjusted HR 1.34, 95%CI 1.16–1.55) and among those with lower MMSE scores (2.52, 2.01–3.17 if <15), not receiving social assistance (1.25, 1.07–1.45), and paying at least 65% of total prescription costs (1.51, 1.30–1.74). It was significantly less likely for patients with frequent physician visits (0.78, 0.66–0.93, for 7–19 vs. <7 visits), higher Chronic Disease Scores (0.74, 0.61–0.89, for 7+ vs. <4), and FAQ scores of 9+ (0.82, 0.69–0.99). Conclusion The likelihood of discontinuing ChEI therapy was high in this real‐world sample of AD patients. Significant predictors included clinical, socioeconomic, and practice factors. Copyright © 2010 John Wiley & Sons, Ltd.