title: Pulmonary function measures predict mortality differently in IPF versus combined pulmonary fibrosis and emphysema.
abstract: The composite physiologic index (CPI) was derived to represent the extent of fibrosis on high-resolution computed tomography (HRCT), adjusting for emphysema in patients with idiopathic pulmonary fibrosis (IPF). We hypothesised that longitudinal change in CPI would better predict mortality than forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC) or diffusing capacity of the lung for carbon monoxide (D(L,CO)) in all patients with IPF, and especially in those with combined pulmonary fibrosis and emphysema (CPFE). Cox proportional hazard models were performed on pulmonary function data from IPF patients at baseline (n = 321), 6 months (n = 211) and 12 months (n = 144). Presence of CPFE was determined by HRCT. A five-point increase in CPI over 12 months predicted subsequent mortality (HR 2.1, p = 0.004). At 12 months, a 10% relative decline in FVC, a 15% relative decline in D(L,CO) or an absolute increase in CPI of five points all discriminated median survival by 2.1 to 2.2 yrs versus patients with lesser change. Half our cohort had CPFE. In patients with moderate/severe emphysema, only a 10% decline in FEV(1) predicted mortality (HR 3.7, p = 0.046). In IPF, a five-point increase in CPI over 12 months predicts mortality similarly to relative declines of 10% in FVC or 15% in D(L,CO). For CPFE patients, change in FEV(1) was the best predictor of mortality.
authors.affiliation: Dept of Internal Medicine, Pulmonary and Critical Care Division, University of Michigan, Ann Arbor, MI, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Schmidt
authors.forename: A M
authors.initials: AM
authors.lastname: Nambiar
authors.forename: N
authors.initials: N
authors.lastname: Tayob
authors.forename: B
authors.initials: B
authors.lastname: Sundaram
authors.forename: M K
authors.initials: MK
authors.lastname: Han
authors.forename: B H
authors.initials: BH
authors.lastname: Gross
authors.forename: E A
authors.initials: EA
authors.lastname: Kazerooni
authors.forename: A R
authors.initials: AR
authors.lastname: Chughtai
authors.forename: A
authors.initials: A
authors.lastname: Lagstein
authors.forename: J L
authors.initials: JL
authors.lastname: Myers
authors.forename: S
authors.initials: S
authors.lastname: Murray
authors.forename: G B
authors.initials: GB
authors.lastname: Toews
authors.forename: F J
authors.initials: FJ
authors.lastname: Martinez
authors.forename: K R
authors.initials: KR
authors.lastname: Flaherty
mesh_terms: D000368:Aged; D002248:Carbon Monoxide / Q000737:chemistry; D004058:Diffusion; D004646:Emphysema / Q000150:complications* / Q000401:mortality; D005260:Female; D005355:Fibrosis; D005541:Forced Expiratory Volume; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000175:diagnosis* / Q000401:mortality; D008137:Longitudinal Studies; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011658:Pulmonary Fibrosis / Q000150:complications* / Q000401:mortality; D012044:Regression Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods; D014797:Vital Capacity
chemical_list: D002248:Carbon Monoxide