Prognostic factors in rapidly progressive interstitial pneumonia

Clinical and other features, as well as prognostic factors for survival, were examined in patients with rapidly progressive interstitial pneumonia. The disease entity included different histological patterns with diverse outcomes, and distinctions were not possible from baseline data. Histological diagnosis was the only significant prognostic determinant.

The aim of the present study was to examine clinical and other features that might allow prognostic distinctions between histological patterns in presentations with rapidly progressive interstitial pneumonia (RPIP), and to assess prognostic factors for survival.

Patients with RPIP among 425 consecutive patients with diffuse lung disease, who underwent surgical lung biopsy, were studied retrospectively. The discriminatory value of clinical and investigative features for identifying disease with a better outcome was evaluated. An a priori comparison was made between diffuse alveolar damage (DAD)/usual interstitial pneumonia with DAD pattern (Group A), and organizing pneumonia/non-specific interstitial pneumonia pattern (Group B).

Twenty-eight patients (6.6%) fulfilled the criteria for RPIP. The diagnosis was Group A disease in 15 (DAD in 10, usual interstitial pneumonia with DAD in 5), and Group B disease in 13 (organizing pneumonia in 8, non-specific interstitial pneumonia in 5). There were no significant differences in initial findings between the groups. Prognosis was significantly better for Group B patients than for Group A patients (P=0.021). Neither BAL nor parenchymal high-resolution CT score was indicative of therapeutic responsiveness or outcome. Distinction between Group A and Group B on the basis of disease pattern was the only significant determinant of prognosis.

RPIP included varied histological patterns with different outcomes, and in many cases these could not be predicted using baseline clinical data. Histology was the only significant predictor of ultimate prognosis.