Background: Patients with interstitial lung disease (ILD) are known to have diminished exercise ability. This study aimed to explore the relationship between nutrition status and body composition parameters with exercise capacity in ILD patients. A second aim focused on assessing the appropriateness of surrogate markers of nutrition status in ILD patients.
Methods: Disease severity was determined by the percentage of predicted forced vital capacity. Exercise capacity was determined using 6-minute walk distance. Nutrition status was assessed using the subjective global assessment (SGA), standardized phase angle (SPhA), and impedance ratio z-score (z-IR). Bioelectrical impedance analysis estimated body composition parameters.
Results: 45 of 79 participants (57%) were malnourished according to the SGA. FFM index z-score (z-FFMI) (r = 0.42, P = .02) and SGA (r = 0.49, P < .01) were significant predictors of exercise capacity independent of disease severity. Age (odds ratio [OR] = 1.1; 95% CI, 1.01-1.25; P = .04), low body mass index (OR = 0.73; 95% CI, 0.57-0.92; P = .01), z-FFMI (OR = 0.34; 95% CI, 0.17-0.68; P < .01), and body fat mass index z-score (OR = 0.39; 95% CI, 0.17-0.91; P = .03) were significantly associated with severe malnutrition. There was no significant difference in SPhA across SGA groups; however, a higher z-IR (poorer cell health) significantly increased the odds of severe malnutrition (OR = 2.75; 95% CI, 1.27-6.03; P = .02).
Conclusion: In ILD patients, malnutrition and loss of FFM negatively impact the ability to perform activities of daily living.
Keywords: body composition; exercise capacity; interstitial lung disease; malnutrition; nutrition status.
© 2021 American Society for Parenteral and Enteral Nutrition.