Clinical study
The effect of pulmonary fibrosis on survival in patients with hypersensitivity pneumonitis

https://doi.org/10.1016/j.amjmed.2003.12.030Get rights and content

Abstract

Purpose

To determine the effect of pulmonary fibrosis on survival in an unselected group of patients with hypersensitivity pneumonitis.

Methods

We identified 72 patients with hypersensitivity pneumonitis confirmed by surgical lung biopsy in the database of the Clinical Interstitial Lung Disease Program at the National Jewish Medical and Research Center. All biopsy specimens were scored according to the presence or absence of fibrosis. Comparisons were made between patients with (fibrotic group) and without (nonfibrotic group) pathologic fibrosis. Vital status was ascertained and Kaplan-Meier curves were plotted. Cox regression analysis was used to determine predictors of survival.

Results

Forty-six patients were classified as fibrotic and 26 as nonfibrotic. Twenty-nine percent had exposure to a bird antigen, 33% had exposure to a microbial antigen, and 38% had unknown exposure. Patients with fibrosis were significantly older, showed greater restrictive lung physiology, and had greater all-cause and respiratory mortality. Median survival in fibrotic patients was 7.1 years, which was significantly less than survival in those without fibrosis. In an age-adjusted regression analysis, antigen class, symptom duration, and lung function had no effect on survival. Only the presence of pathologic fibrosis was predictive of increased mortality (hazard ratio = 6.01; 95% confidence interval: 1.68 to 21.45; P = 0.006).

Conclusion

Pulmonary fibrosis is associated with diminished survival in patients with hypersensitivity pneumonitis.

Section snippets

Case definition

We identified 85 patients in the database of the Clinical Interstitial Lung Disease Program at the National Jewish Medical and Research Center, for the period of 1982 to 2000, who had a primary diagnosis of hypersensitivity pneumonitis and who had undergone surgical lung biopsy. Two expert lung pathologists (CDC, RMT) who were blinded to all clinical information independently reviewed the biopsy specimens. The pathologic features of a predominantly lymphoplasmocytic interstitial pneumonitis

Results

Forty-six patients were classified as having fibrotic hypersensitivity pneumonitis and 26 as nonfibrotic (Table 1). Fibrotic patients were significantly older, and a higher proportion had symptoms for more than 1 year compared with nonfibrotic subjects. Otherwise, there were no significant differences in smoking history, antigen exposure, and symptoms. Precipitin antibodies were positive in 64% of patients (n = 29) with an identified exposure, including 75% (18/24) of those exposed to a

Discussion

Our findings demonstrate that the presence of pulmonary fibrosis in patients with hypersensitivity pneumonitis is associated with significantly increased all-cause and respiratory mortality. Fibrosis was the best predictor of diminished survival of the variables tested, including symptom duration, antigen type, smoking status, and pulmonary function.

Hypersensitivity pneumonitis has generally been associated with low mortality (23). However, prior investigations have been largely limited to

References (38)

  • M Selman

    Hypersensitivity Pneumonitis

  • M Ando et al.

    A new look at hypersensitivity pneumonitis

    Curr Opin Pulm Med

    (1999)
  • S Monkare et al.

    Farmer's lung—a 5-year follow-up of 86 patients

    Clin Allergy

    (1987)
  • S Bourke et al.

    Longitudinal course of extrinsic allergic alveolitis in pigeon breeders

    Thorax

    (1989)
  • M Lalancette et al.

    Farmer's lunglong-term outcome and lack of predictive value of bronchoalveolar lavage fibrosing factors

    Am Rev Respir Dis

    (1993)
  • R Erkinjuntti-Pekkanen et al.

    Long-term risk of emphysema in patients with farmer's lung and matched control farmers

    Am J Respir Crit Care Med

    (1998)
  • R.A Barbee et al.

    The long-term prognosis in farmer's lung

    Am Rev Respir Dis

    (1968)
  • S.R Braun et al.

    Farmer's lung diseaselong-term clinical and physiologic outcome

    Am Rev Respir Dis

    (1979)
  • R Perez-Padilla et al.

    Mortality in Mexican patients with chronic pigeon breeder's lung compared with those with usual interstitial pneumonitis

    Am Rev Respir Dis

    (1993)
  • Cited by (220)

    View all citing articles on Scopus
    View full text