The effect of low body mass index on the development of chronic obstructive pulmonary disease and mortality

Abstract

Background: Sarcopenia may worsen disease progression and lead to poor outcomes in chronic obstructive pulmonary disease (COPD).

Objectives: We aimed to determine the effect of BMI on the development of COPD and mortality.

Methods: We enrolled 437 584 participants registered in the physical health check-up cohort database of the Korean National Health Interview Survey from 2002 to 2003, and we defined COPD diagnosis based on the ICD-10 code and prescribed medication. BMI (kg m^-2 ) classified them to five groups (low BMI < 18.5, normal BMI 18.5-23, overweight 23-25, obesity 25-30, severe obesity ≥30) at baseline.

Results: Participants in the low BMI group had a significantly higher rate of COPD development for 13 years (7.6%) than those in other groups (3.4-4.1%, P < 0.0001). Amongst never or light smokers, COPD development in the low BMI group (5.6-6.7%) was significantly higher than that in other groups (2.8-4.7%). Similarly, amongst participants with a smoking history of ≥30 years, COPD development in the low BMI group (20.1%) was higher than those in other groups (8.4-12.4%). On multivariable analysis, normal or higher than normal body weight was significantly protective against the development of COPD (hazard ratio [HR], 0.609-0.739,) compared to low BMI. COPD-free-survival (HR, 0.491-0.622) and overall survival (HR, 0.440-0.585) were also better in them compared to those with low BMI (all P < 0.0001).

Conclusions: Low BMI is an important risk factor for COPD development and mortality. Maintaining adequate body weight may reduce the risk for COPD development and mortality.

Keywords: body mass index; chronic obstructive pulmonary disease; mortality; sarcopenia; survival.