Mortality in Elderly Patients Taking Furosemide: Prospective Cohorts Study

Abstract

Objectives. Low blood pressure (BP) has been proposed as a risk factor of death in elderly patients. However, this association could be partially accounted for by the deleterious effects of BP-lowering drugs. We analyzed whether these drugs are associated to an increased risk of death in elderly patients taking multiple potential confounders into account. Design. This is a prospective cohort study. Setting and Participants. Probabilistic sample of 772 community-dwelling patients aged >65 years living in Spain, who were appointed for an initial clinical visit and followed up through telephone calls 4, 6, 9, 12, and 60 months afterwards. Methods. At baseline visit, BP was measured using standardized methods, and BP medications and risk factors of death in elderly patients (BMI, oxygen saturation, toxic habits, comorbidity, muscular strength, and functional and cognitive capacity) were collected. During the follow-up, the vital status of patients and the date of death were ascertained. Results. During a median 5-year follow-up, 226 all-cause deaths occurred among the 686 participants included in the analysis. In a Cox regression model that included all the BP drug classes, diuretics and nitrites were significantly associated with mortality ( $p<0.005$ ). Within diuretics, furosemide was found to be responsible for the association of the group. In multivariable Cox regression models adjusted for BP and the rest of the mortality risk factors, furosemide remained as the only BP drug that was independently associated with mortality (hazard ratio 2.34; $p<0.01$ ). Conclusions. Furosemide was prospectively associated with increased mortality in older people. If confirmed, this drug should be taken into account by prescribers and considered a confounder in BP studies.