Sex differences in multimorbidity and polypharmacy trends: A repeated cross-sectional study of older adults in Ontario, Canada

Abstract

Background Multimorbidity is increasing among older adults, but the impact of these recent trends on the extent and complexity of polypharmacy and possible variation by sex remains unknown. We examined sex differences in multimorbidity, polypharmacy (5+ medications) and hyper-polypharmacy (10+ medications) in 2003 vs 2016, and the interactive associations between age, multimorbidity level, and time on polypharmacy measures. Methods and findings We employed a repeated cross-sectional study design with linked health administrative databases for all persons aged ≥66 years eligible for health insurance in Ontario, Canada at the two index dates. Descriptive analyses and multivariable logistic regression models were conducted; models included interaction terms between age, multimorbidity level, and time period to estimate polypharmacy and hyper-polypharmacy probabilities, risk differences and risk ratios for 2016 vs 2003. Multimorbidity, polypharmacy and hyper-polypharmacy increased significantly over the 13 years. At both index dates prevalence estimates for all three were higher in women, but a greater absolute increase in polypharmacy over time was observed in men (6.6% [from 55.7% to 62.3%] vs 0.9% [64.2%-65.1%] for women) though absolute increases in multimorbidity were similar for men and women (6.9% [72.5%-79.4%] vs 6.2% [75.9%-82.1%], respectively). Model findings showed that polypharmacy decreased over time among women aged < 90 years (especially for younger ages and those with fewer conditions), whereas it increased among men at all ages and multimorbidity levels (with larger absolute increases typically at older ages and among those with 4 or fewer conditions). Conclusions There are sex and age differences in the impact of increasing chronic disease burden on changes in measures of multiple medication use among older adults. Though the drivers and health consequences of these trends warrant further investigation, the findings support the heterogeneity and complexity in the evolving association between multimorbidity and polypharmacy measures in older populations.

Fifteen-year trajectories of multimorbidity and polypharmacy in Dutch primary care—A longitudinal analysis of age and sex patterns

“…The few studies that have focused on chronic disease in relation to polypharmacy have generally been performed in specific chronic disease populations [10]. In the overall population, and particularly among older patient groups, chronic disease has been shown to be a significant risk factor for polypharmacy [9].…”

“…Although prevalence increases substantially with age, in absolute terms multimorbidity is much more common in those aged 65 years or less [8,9]. Some studies have indicated interactive associations between sex, age and multimorbidity, which may depend on medical, lifestyle and social factors influencing the health status of patients [8,10]. Data on the age at which multimorbidity begins and how it evolves over time are urgently needed in order to develop focused interventions that help prevent multimorbidity and associated adverse health outcomes [11].…”

“…As with multimorbidity, the prevalence of polypharmacy among persons aged 65 and older has increased significantly over the past 20 years, with recent international estimates ranging between 50-66% [7,10]. Multimorbidity and polypharmacy are closely related.…”

“…Polypharmacy is frequently found among patients with multimorbidity, and the number of their chronic conditions is an even stronger predictor of the number of prescribed medications they are taking than age is [7]. However, the relationship between multimorbidity and polypharmacy is complex [3], and the interaction between them is both synergistic and antagonistic [1,7,10,12,13]. Maxwell et al (2021) note that recent studies have explored broad trends in multimorbidity and/or polypharmacy but few have examined sex-and age-specific trends, or investigated the impact of multimorbidity and age on medication use over time [10].…”

“…However, the relationship between multimorbidity and polypharmacy is complex [3], and the interaction between them is both synergistic and antagonistic [1,7,10,12,13]. Maxwell et al (2021) note that recent studies have explored broad trends in multimorbidity and/or polypharmacy but few have examined sex-and age-specific trends, or investigated the impact of multimorbidity and age on medication use over time [10].…”