Purpose: The purpose of this study was to determine whether excessive polypharmacy is associated with a higher survival rate in polypathological patients.
Patients and methods: An observational, prospective, and multicenter study was carried out on those polypathological patients admitted to the internal medicine and acute geriatrics departments between March 1 and June 30, 2011. For each patient, data concerning age, sex, comorbidity, Barthel and Lawton-Brody indexes, Pfeiffer's questionnaire, socio-familial Gijon scale, delirium, number of drugs, and number of admissions during the previous year were gathered, and the PROFUND index was calculated. Polypharmacy was defined as the use of ≥ 5 drugs and excessive polypharmacy as the use of ≥ 10. A 1-year long follow-up was carried out. A logistic regression model was performed to analyze the association of variables with excessive polypharmacy and a Cox proportional hazard model to determine the association between polypharmacy and survival.
Results: We included 457 polypathological patients. Mean age was 81.0 (8.8) years and 54.5% were women. The mean number of drugs used was 8.2 (3.4). Excessive polypharmacy was directly associated with heart disease [hazard ratio (HR) 2.33 95% CI 1.40-3.87; p =0.001], respiratory disease [HR 1.87 95% CI 1.13-3.09; p = 0.01], peripheral artery disease/diabetes with retinopathy and/or neuropathy [HR 2.02 95% CI 1.17-3.50; p = 0.01], and the number of admissions during the previous year [HR 1.21 96%CI 1.01-1.44; p = 0.04]. It was inversely associated with delirium [HR 0.48 95% CI 0.25-0.91; p = 0.02]. There were no statistical differences regarding the probability of 1-year survival between patients with no polypharmacy, with simple polypharmacy, and with excessive polypharmacy (0.66, 0.60, and 0.57, respectively, p = 0.12).
Conclusions: A greater use of drugs may not be harmful but is also not associated with a higher probability of survival in polypathological patients.