Factors affecting prognosis of idiopathic interstitial pneumonia

Idiopathic interstitial pneumonia (IIP) is a progressive and often fatal pulmonary disorder, and evaluating the prognosis of patients with IIP has never been sufficient. Accordingly, factors including clinical features, laboratory data, cellular components in bronchoalveolar lavage (BAL) fluid and response to corticosteroid therapy were analyzed in 35 patients with IIP whose median age of respiratory onset was 60 years (range; 37-77 years). Nineteen patients (54.3%) were in the active stage of IIP and 16 of them were treated with corticosteroids. Significant prognostic factors were the neutrophil percentage in BAL fluid, interstitial shadows on chest radiograph, pulmonary function, blood oxygen level, grade of dyspnea, and disease activity at the initial examination. Patients in the active stage showed higher proportions of neutrophils and eosinophils in BAL fluid than those in the non-active stage. Despite corticosteroid therapy, the survival of patients in the active stage was significantly shorter than those in the non-active stage. Fifty percent of the patients treated with corticosteroids were regarded as responders at 1 month after the initiation of therapy; however, there was no significant difference between responders and non-responders in terms of survival time. In conclusion, disease activity and neutrophils in BAL fluid may be important predictors of the prognosis of IIP.