Abstract
Background:
Polypharmacy is common among elderly individuals living in nursing homes due to the high burden of chronic diseases. Although multiple medications are often necessary, their combined use increases the risk of adverse drug reactions (ADRs), drug–drug interactions, and hospital admissions. Limited local data are available from Pakistan regarding the impact of polypharmacy in long-term care settings.
Objective:
This study evaluated the association between polypharmacy and the incidence of adverse drug reactions among elderly residents in nursing homes. Medication patterns, frequency of drug-drug interactions, and related hospitalizations were analyzed to assess the risks of multiple drug combinations.
Methods:
An observational cohort study was conducted over a 12-month period at a tertiary hospital in Karachi in collaboration with affiliated nursing homes. Elderly residents aged ≥65 years with complete medical records were included. Polypharmacy was defined as the regular use of five or more medications, while excessive polypharmacy was defined as ten or more medications. Data were collected on demographic characteristics, comorbidities, medication profiles, documented ADRs, drug–drug interactions, and ADR-related hospitalizations. Statistical analysis included descriptive statistics, chi-square testing, and multivariate logistic regression. A p-value <0.05 was considered statistically significant.
Results:
A total of 300 elderly residents were included (mean age 73.8 ± 6.4 years; 57.3% female). Polypharmacy was present in 80% of residents, and 23.3% were exposed to excessive polypharmacy. Overall, 39.3% of participants experienced at least one ADR during the study period. ADR incidence increased significantly with medication burden: 13.3% in residents taking <5 drugs, 38.2% in those taking 5–9 drugs, and 64.3% in those taking ≥10 drugs (p <0.001). Drug–drug interactions were identified in 65.3% of residents, with major interactions more common in the excessive polypharmacy group. ADR-related hospitalizations occurred in 20.3% of residents and were highest among those with excessive polypharmacy (42.9%). After adjusting for age, gender, and comorbidities, excessive polypharmacy remained an independent predictor of ADR-related hospitalization (Adjusted OR = 3.8; 95% CI: 2.1–6.4; p <0.001).
Conclusion:
Polypharmacy is highly prevalent among elderly nursing home residents in Karachi and is strongly associated with increased risk of adverse drug reactions and hospitalization. Excessive medication use represents a significant and modifiable risk factor. Regular medication review, rational prescribing, and structured monitoring strategies are essential to improve medication safety in this vulnerable population.