The Impact of Age and Sex Concordance Between Patients and Physicians on Medication Adherence: A Population-Based Study

PURPOSE: Age or sex concordance (same sex or same age range) may also be associated with medication adherence but was not fully investigated. We aim to quantify the impact of age and sex concordance on optimal adherence to statin medications. PATIENTS AND METHODS: A retrospective cohort study was conducted using population-based health administrative data from Saskatchewan, Canada. Participants were individuals newly initiated on statin medications between January 1, 2012, and December 31, 2017. The outcome was optimal adherence (proportion of days covered ≥ 80%) measured at one year after the first statin claim. The independent variables were sex and age concordance (age within five years) between patients and prescribers. The association between adherence outcome and sex/age concordance was analyzed by multivariable logistic regression models using generalized estimating equations controlled by a package of potential confounding factors. RESULTS: Among 51,874 new statin users, 20.6% (n = 10,710) were age concordant with prescriber. The vast majority of age concordance occurred in patients younger than 66 years (88.6%, 9,486/10,710). Sex concordance was observed in 62.8% (n = 32,551) of patients and age-sex combined concordance in 13.2% (n = 6,856). Among patients younger than 66 years (n = 36,641/51,874, 70.6%), age concordance did not have a significant impact on optimal adherence [adjusted OR (aOR) = 1.02, 95% CI 0.97 to 1.07]. Weak association between sex concordance (aOR = 1.05, 95% CI 1.00 to 1.11), and age-sex combined concordance (aOR = 1.05, 95% CI 0.99 to 1.12) was observed. CONCLUSION: Age and sex concordance were not statistically significant predictors of optimal statin adherence. However, a weak association was detected for sex concordance. Future studies should examine this factor in different health care settings.