Prevalence of central nervous system-active polypharmacy in a cohort of older adults in Argentina.

Background: Central nervous system (CNS)-active polypharmacy is frequent and potentially harmful in older patients. Data on its burden outside the USA and European countries remain limited.

Aims: To estimate the period prevalence of and factors associated with out-of-hospital CNS-active polypharmacy in older adults.

Method: We used data from a cohort of out-patients aged ≥60 years affiliated to the Hospital Italiano de Buenos Aires' health maintenance organisation on 1 January 2021. A CNS-active polypharmacy event was defined as the concurrent exposure to ≥3 CNS-active medications (i.e. antidepressants, anti-epileptics, antipsychotics, benzodiazepines, Z-drugs and opioids) through filled out-of-hospital prescriptions. We calculated the period prevalence of CNS-active polypharmacy for 2021. We identified factors associated with CNS-active polypharmacy using a multivariable logistic regression model to estimate odds ratios and 95% confidence intervals (CI).

Results: We included 63 857 patients. Pre-existing mental health diagnoses included anxiety (21%), depressive (14%) and sleep (11%) disorders. CNS-active polypharmacy occurred in 4535 patients, for a period prevalence of 7.1% (95% CI: 6.9-7.3%). The combination of an antidepressant, an antipsychotic and a benzodiazepine accounted for 21% of the CNS-active polypharmacy events. Frontotemporal dementia (odds ratio: 14.67; 95% CI: 4.47-48.20), schizophrenia (odds ratio: 7.93; 95% CI: 4.64-13.56), bipolar disorder (odds ratio: 7.20; 95% CI: 5.45-9.50) and depressive disorder (odds ratio: 3.50; 95% CI: 3.26-3.75) were associated with CNS-active polypharmacy.

Conclusions: One in 14 adults aged 60 years and older presented out-of-hospital CNS-active polypharmacy. Future studies should evaluate measures to reduce CNS-active medication use in this population.