Body mass index (BMI) has prognostic value in patients with chronic lung disease. Pulmonary rehabilitation improves quality of life. This study investigated whether BMI predicts change in disease-specific quality of life following pulmonary rehabilitation.
Subjects (N = 61), who completed pulmonary rehabilitation, were classified by BMI as low (<23 kg/m2), middle (≥23 and <33 kg/m2), or high (≥33 kg/m2). Outcomes were changes in disease- specific quality of life measured by the following domains of the Chronic Respiratory Questionnaire Self-Reported (CRQ-SR): dyspnea, mastery, emotion, and fatigue. Subjects completed CRQ-SR at the start and end of pulmonary rehabilitation. Multivariable regression was used to compare change in CRQ-SR scores of each domain by BMI group controlling for forced expiratory volume in 1 second.
Subjects were 68.9 ± 9.0 years old and were all white men. At baseline, the low-BMI group had lower mean forced expiratory volume in 1 second (0.96 ± 0.28) than the middle (1.29 ± 0.48, P = .02) and high (1.37 ± 0.38, P = .01) BMI groups. Collectively, subjects improved on CRQ-SR dyspnea (P < .004), mastery (P < .008), emotion (P < .03), and fatigue (P < .005). In multivariable models, the high-BMI group had greater improvement on the CRQ-SR domains for fatigue (β = 3.5 ± 1.0, P = .0008) and mastery (β = 4.8 ± 1.6, P = .003) than the middle-BMI group.
Pulmonary rehabilitation results in improved disease-specific quality of life. BMI influences this improvement and should be considered in the assessment, plan of care, and outcomes in response to pulmonary rehabilitation for patients with chronic respiratory disease.