Surfactant protein A predicts survival in idiopathic pulmonary fibrosis.
The purpose of this study was to determine if the measurement of surfactant protein A (SP-A) in bronchoalveolar lavage (BAL) fluid predicts survival in patients with idiopathic pulmonary fibrosis (IPF). We performed BAL on 44 patients with IPF and 33 healthy volunteers. SP-A and total phospholipid (PL) were measured in the surfactant pelleted by centrifugation and expressed as a ratio to account for differences in the alveolar surface area sampled. The mean SP-A/PL was lower in patients with IPF than in healthy volunteers (31.8 +/- 2.8 versus 63.9 +/- 6.4 micrograms/mumol, p = 0.006) and in patients who died within 2 yr than in those who survived (23.4 +/- 2.6 versus 37.5 +/- 4.2 micrograms/mumol, p = 0.015). Using Cox's proportional hazard model, we found that SP-A/PL modeled continuously was associated with survival time (p = 0.002). The 5-yr survival of patients with SP-A/PL above the median level for all patients with IPF (29.7 micrograms/mumol) was more than twice that of patients below the median (68 versus 30%, p = 0.007). SP-A/PL improved upon prediction of survival modeled by most routine physiologic variables with the exception of percent predicted TLC or the multifarious clinical-radiographic-physiologic score (CRP). Cellular analysis of lavage did not predict survival in this cohort of patients. We conclude that SP-A/PL is a biochemical marker in lavage that predicts survival in patients with IPF.
McCormack
F X
FX
Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206, USA.
King
T E
TE
Bucher
B L
BL
Nielsen
L
L
Mason
R J
RJ
McCormac
F X
FX
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D016022:Case-Control Studies; D002423:Cause of Death; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D005544:Forecasting; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000032:analysis; D016016:Proportional Hazards Models; D011510:Proteolipids / Q000032:analysis*; D011658:Pulmonary Fibrosis / Q000378:metabolism* / Q000503:physiopathology; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000032:analysis*; D012907:Smoking / Q000378:metabolism; D015996:Survival Rate; D014109:Total Lung Capacity; D014797:Vital Capacity
D015415:Biomarkers; D006023:Glycoproteins; D010743:Phospholipids; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants