Inverse care law in polypharmacy and medication review among older adults: a population-based study

Background

Polypharmacy, a risk factor for falls, hospitalizations, morbidity, and mortality, is a growing challenge for primary care and public health, and medication review is recommended to optimize treatments and reduce these risks. Socio-economic pattern in polypharmacy and medication review is poorly documented.

Methods

We performed a secondary analysis of the 2024 International Health Policy Survey in Switzerland, based on a representative sample of 2’634 community-dwelling adults aged ≥65. We estimated the prevalence of polypharmacy (≥5 prescribed medications) and of medication review in the last 12 months as reported by participants. Socio-economic status was defined by income and education. We assessed the associations between participants’ characteristics, polypharmacy, and medication review using stratified analyses and prevalence ratios (PRs). Analyses were weighted to account for the survey design.

Results

A total of 2’152 participants were included (51% women; mean age: 75 years [min: 65; max: 101]). Overall, 20% reported polypharmacy. Prevalence increased with age (PR = 2.4 for ≥85 years vs 65-74, 95% CI 1.7-3.3), lower education level (PR = 1.4 for primary vs tertiary, 95% CI 1.0-2.0), and lower income (PR = 1.3 for CHF <5000 vs ≥ 9000, 95% CI 0.9-1.9). Among participants with polypharmacy, 84% (95% CI 79-89%) reported a medication review, and this proportion was slightly lower among those with lower income compared to those with higher income.

Conclusions

Polypharmacy is frequent among older adults in Switzerland, particularly among those with lower socio-economic status. Most older adults with polypharmacy reported a medication review, but less so among those with lower-income, suggesting an inverse care law phenomenon. Interventions to monitor and optimize medications use among older adults should account for the socio-economic patterning of polypharmacy.

Key messages

• Polypharmacy is common and socially patterned among older adults in Switzerland.

• Medication review reaches most older adults with polypharmacy, but socio-economic inequalities persist.