title: Fat-free mass index predicts survival in patients with idiopathic pulmonary fibrosis.
abstract: Detailed body composition, such as fat-free mass, has not been examined in idiopathic pulmonary fibrosis (IPF). We investigated whether the fat-free mass index (FFMI), an index of lean body mass, predicted survival.
  
  
  
  Forty-four patients with IPF were enrolled in the study. Their body composition was assessed using direct segmental multi-frequency bioelectrical impedance analysis. The degree of correlation between variables of body composition and other variables such as forced vital capacity (FVC) and survival was examined.
  
  
  
  There was a significant positive correlation between FFMI and FVC, diffusion capacity of the lung for carbon monoxide (DLCO) and 6-min walk distance, and a significant negative correlation with age. However, there was no significant correlation between FFMI and percentage predicted FVC or DLCO, with the degree of correlation being similar to that observed for BMI. The mean observation period in the survival analysis was 837.5 ± 407.5 days. A univariate Cox proportional hazard model showed that several variables, but not BMI, were associated significantly with survival. FFMI (hazard ratio (HR): 0.64, 95% CI: 0.43-0.94, P = 0.02) and percentage predicted FVC (HR: 0.96, 95% CI: 0.93-0.99, P=0.008) were significant factors in a multivariate model.
  
  
  
  We conclude that FFMI is a significant independent predictor of survival in patients with IPF.
authors.affiliation: Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishiyama
authors.affiliation: Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamazaki
authors.affiliation: Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sano
authors.affiliation: Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Iwanaga
authors.affiliation: Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Higashimoto
authors.affiliation: Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kume
authors.affiliation: Department of Respiratory Medicine and Allergology, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tohda
mesh_terms: D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D002248:Carbon Monoxide; D017097:Electric Impedance; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000503:physiopathology*; D008168:Lung; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D011653:Pulmonary Diffusing Capacity; D015996:Survival Rate; D014797:Vital Capacity; D000070857:Walk Test
chemical_list: D002248:Carbon Monoxide
keywords: body composition; fat-free mass; idiopathic pulmonary fibrosis; survival