Life expectancy (LE) and loss-of-LE for patients with chronic obstructive pulmonary disease

Abstract

Background and objectives: Prognosis of COPD is usually expressed as a 3-year survival rate, which might not be easily understood by lay people. This study estimates the life expectancy (LE) and loss-of-LE for COPD patients with different GOLD stages and patients with a history of acute exacerbation (AE) requiring hospitalization (severe AE) in the preceding year.

Methods: 532 patients who were diagnosed with COPD according to the GOLD criteria at NCKU hospital between 2006 and 2016 were recruited. Survival was estimated by Kaplan-Meier method, and extrapolated to lifetime to obtain the LE. The loss-of-LE was quantified by subtracting the LE of the COPD cohort from national life tables. The survival of patients with severe AE history was validated by a nation-wide cohort from the National Health Insurance dataset.

Results: The survival of patients with severe stage COPD (GOLD grades 3 and 4) was almost the same as those patients with a history of severe AE and the loss-of-LE for the former and the latter were 9.3 (1.1) and 9.4 (1.3) years, respectively. The nation-wide cohort with severe AE history (n = 44,764) showed a loss-of-LE of 8.3 (0.1) years. The loss-of-LE of patients with moderate stage COPD (GOLD grade 2) was 6.2 years, but no reduction in LE was noted for mild stage COPD (GOLD grade 1).

Conclusions: We successfully estimated LE and loss of LE in COPD patients under the GOLD criteria. The survival of severe stage COPD patients is almost the same as those with severe AE history, or about 8-9 years of life lost.

Keywords: Acute exacerbation; COPD; Life expectancy; Loss of life expectancy; Survival.