15-years mortality in asthma-COPD overlap syndrome (ACOS) elderly population

Abstract

Background: The coexistence of asthma and chronic obstructive pulmonary disease (Asthma-COPD Overlap Syndrome: ACOS) is increasingly recognized. Data about the prevalence of ACOS in the elderly and its prognostic implications are unknown. Aim: To evaluate the long-term mortality of ACOS in an elderly population. Methods: 1970 subjects, aged >65 yrs, were enrolled in the population-based SA.R.A. Study. ACOS was defined as: not fully reversible airflow limitation + a) history of asthma or b) very positive bronchodilator test (increase in FEV1 ≥15% and ≥400 ml) + atopy + weezing. The prevalence of ACOS and 15-years mortality rates were assessed in 1063 subjects with complete clinical, lung functional, and follow-up data. Physical performance, disease-related disability and health related quality of life (HRQL) were also evaluated. Results: ACOS was found in 11.1% of subjects (1/3 of those previously diagnosed with COPD and 1/5 of those with asthma). ACOS was associated with impaired physical performance, functional ability, and HRQL. Individuals with ACOS had higher mortality rates than controls (7.17 per 100 person-years; mortality rate ratio: 1.83). After adjustment for the main confounders, the risk of all-cause mortality remained significantly increased in subjects with ACOS (HR:1.82, 95%CI:1.38-2.38), COPD (HR:1.99, 95%CI:1.59-2.49), but not asthma. Male gender, advanced age, high smoke exposure, depression, and poor education were associated with an increased risk of dying. Conclusions: Long term mortality of ACOS was similar to COPD, and worse than asthma and healthy controls. ACOS had a significant impact on physical performance, functional ability, and HRQL in elderly subjects.