It is unknown if the radiographic fibrosis score predicts mortality in persistent hypersensitivity pneumonitis (HP) and if survival is similar to that observed in idiopathic pulmonary fibrosis (IPF) when adjusting for the extent of radiographic fibrosis.

We reviewed records from 177 patients with HP and 224 patients with IPF whose diagnoses were established by multidisciplinary consensus. Two thoracic radiologists scored high-resolution CT (HRCT) scan lung images. Independent predictors of transplant-free survival were determined using a Cox proportional hazards analysis. Kaplan-Meier survival curves were constructed, stratified by disease Viagra 100mg pills  as well as fibrosis score.

HRCT scan fibrosis score and radiographic reticulation independently predicted time to death or lung transplantation. Clinical predictors included a history of cigarette smoking, auscultatory crackles on lung examination, baseline FVC, and FEV1/FVC ratio. The majority of HP deaths occurred in patients with both radiographic reticulation and auscultatory crackles on examination, compared with patients with only one of these manifestations (P < .0001). Patients with IPF had worse survival than those with HP at any given degree of radiographic fibrosis (hazard ratio 2.31; P < .01).

Survival in patients with HP was superior to that of those with IPF with similar degrees of radiographic fibrosis. The combination of auscultatory crackles and radiographic reticulation identified patients with HP who had a particularly poor outcome.

Hypersensitivity pneumonitis (HP) is a diffuse parenchymal lung disease characterized by an immunologic reaction to an inhaled organic antigen. Patients with HP, especially those with acute manifestations, generally have a favorable outcome, particularly when the causative antigen is identified and removed. However, patients may alternatively develop a chronic form of disease that can be characterized by the presence of fibrosis on histopathologic or radiographic evaluation. Data from the National Center for Health Statistics show that age-adjusted mortality rates from HP have increased significantly (P < .0001) from 0.09 to 0.29 per million between 1980 and 2002 in US adults. Both radiographic and pathologic fibrosis are associated with an increase in all-cause mortality in HP, but it is unclear if these are independent risk factors when adjusting for other clinical and physiologic predictors.