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Comparative Study
. 2009 Jun;135(6):1557-1563.
doi: 10.1378/chest.08-2209. Epub 2009 Mar 2.

Serum surfactant protein-A is a strong predictor of early mortality in idiopathic pulmonary fibrosis

Brent W Kinder  1 , Kevin K Brown  2 , Francis X McCormack  3 , Joachim H Ix  4 , Alma Kervitsky  2 , Marvin I Schwarz  2 , Talmadge E King Jr  5
Affiliations
Comparative Study

Serum surfactant protein-A is a strong predictor of early mortality in idiopathic pulmonary fibrosis

Brent W Kinder et al. Chest. 2009 Jun.

Abstract

Background: Serum surfactant protein (SP) A and SP-D had prognostic value for mortality in patients with idiopathic pulmonary fibrosis (IPF) in prior studies before the reclassification of the idiopathic interstitial pneumonias. We hypothesized that baseline serum SP-A and SP-D concentrations would be independently associated with mortality among patients with biopsy-proven IPF and would improve a prediction model for mortality.

Methods: We evaluated the association between serum SP-A and SP-D concentrations and mortality in 82 patients with surgical lung biopsy-proven IPF. Regression models with clinical predictors alone and clinical and biomarker predictors were used to predict mortality at 1 year.

Results: After controlling for known clinical predictors of mortality, we found that each increase of 49 ng/mL (1 SD) in baseline SP-A level was associated with a 3.3-fold increased risk of mortality (adjusted hazard ratio, 3.27; 95% confidence interval, 1.49 to 7.17; adjusted p = 0.003) in the first year after presentation. We did not observe a statistically significant association between serum SP-D and mortality (adjusted hazard ratio, 2.04; p = 0.053). Regression models demonstrated a significant improvement in the 1-year mortality prediction model when serum SP-A and SP-D (area under the receiving operator curve [AROC], 0.89) were added to the clinical predictors alone (AROC, 0.79; p = 0.03).

Conclusions: Increased serum SP-A level is a strong and independent predictor of early mortality among patients with IPF. A prediction model containing SP-A and SP-D was substantially superior to a model with clinical predictors alone.

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Conflict of interest statement

The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Figures

Figure 1
Figure 1
The Kaplan-Meier method survival curve of patients with IPF based on serum SP-A level tertiles (≤ 80.4 ng/mL, 81 to 123 ng/mL, and > 123 ng/mL; p = 0.009 [log rank test]; patients at risk: year 1, 68; year 2, 55; year 3, 43).
Figure 2
Figure 2
The ROCs for the clinical vs the clinical and serum SP models (p = 0.03) in predicting 1-year mortality in patients with IPF. Model 1 includes clinical parameters (age, gender, race, smoking status, FVC, Dlco, and alveolar-arterial oxygen gradient). Model 2 includes clinical parameters and serum SP-A and SP-D levels.
See this image and copyright information in PMC

References

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