Abstract
AIMS: Diuretic drugs may theoretically improve respiratory health outcomes in chronic obstructive pulmonary disease (COPD) through several possible mechanisms, but they might also lead to respiratory harm. We evaluated the association of incident oral diuretic drug use with respiratory-related morbidity and mortality among older adults with COPD. METHODS: This was a population-based, retrospective cohort study using health administrative data from Ontario, Canada, for the period 2008-2013. We identified adults aged 66 years and older with nonpalliative COPD using a validated algorithm. Respiratory-related morbidity and mortality were evaluated within 30 days of incident oral diuretic drug use compared to nonuse using Cox proportional hazard regression and applying inverse probability of treatment weighting using the propensity score to minimize confounding. RESULTS: Out of 99 766 individuals aged 66 years and older with COPD identified, incident diuretic receipt occurred in 51.7%. Relative to controls, incident diuretic users had significantly increased rates for hospitalization for COPD or pneumonia [hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.07-1.40], as well as more emergency room visits for COPD or pneumonia (HR 1.35, 95% CI 1.18-1.56), COPD or pneumonia-related mortality (HR 1.41; 95% CI 1.04-1.92) and all-cause mortality (HR 1.20, 95% CI 1.06-1.35). The increased respiratory-related morbidity and mortality observed were specifically as a result of loop diuretic use. CONCLUSIONS: Incident diuretic drugs, and more specifically loop diuretics, were associated with increased rates of respiratory-related morbidity and mortality among older adults with nonpalliative COPD. Further studies are needed to determine if this association is causative or due to unresolved confounding.