Background: Aging results in a progressive decrease in the renal functional reserve; polypharmacy can have negative effects. Objective: Analyze whether polypharmacy and other factors increase the probability of reduced glomerular filtration rate (GFR) in older adults. Materials and methods: A secondary analysis of data from 311 adults >= 60 years of age was carried out. The outcome variable was reduced GFR; the main exposure variable was the number of drugs prescribed, adjusting for sociodemographic and functional covariates (age, gender, state of union, education level, body mass index, multimorbidity, cognitive impairment, frailty, functionality, and therapeutic adherence), and drugs with known negative effects on kidney function. A logistic regression model was developed to estimate the association between the number of medications and the reduction in GFR, adjusted for covariates. Results: Among the 22% of the patients in whom reduced GFR was identified, males made up the highest proportion. The number of drugs and the interaction between being male and having hypertension were associated with reduced GFR; in hypertensive men, this probability increased progressively from 1 to 13 drugs. Conclusion: Selective vulnerability of hypertensive men to reduced GFR from drug use was confirmed; the risk increases progressively with the number of drugs used.
