Application and validity evaluation of fat-free mass index in malnutrition screening in patients with stable chronic obstructive pulmonary disease

Abstract

Objective To evaluate the validity of fat-free mass index in malnutrition screening in patients with stable chronic obstructive pulmonary disease(COPD). Methods A total of 235 patients with stable COPD were enrolled from out-patient, and each of them was measured for anthropometric indicators, urine creatinine and blood biochemical indicators. Body composition was assessed by bioelectrical impedance analysis and their body mass index (BMI) and fat-free mass index (FFMI) were calculated. Body composition assessment (BCA), BMI, FFMI and mini-nutritional assessment(MNA)were used for screening malnutrition in enrolled patients. Using BCA as the diagnosis standard of malnutrition, the sensitivity, specificity, Youden′s index (YI) and consistency of FFMI, BMI, MNA with BCA were compared. Results The incidence of malnutrition screened by BCA, FFMI, BMI and MNA were 47.6%, 48.5%, 8.3%, 53.2% respectively. The sensitivity of FFMI, BMI and MNA screening for malnutrition were 92%, 33%, and 86%, the specificity were 91%, 95% and 75%, the Youden's index (YI) were 0.83, 0.28 and 0.38 and Kappa value were 0.84, 0.29, 0.60 respectively (all P<0.01). Conclusions Compared with BMI and MNA, FFMI shows higher sensitivity, specificity, YI and agreement with BCA, which is suitable for patients with stable COPD in screening malnutrition Key words: Pulmonary disease, chronic obstructive; Malnutrition; Fats; Body mass index