A Retrospective Study of Prognostic Factors in Patients with Interstitial Pneumonia Receiving Long-Term Oxygen Therapy - Prognosis of IP Patients Receiving LTOT

PURPOSE: We retrospectively analyzed patients with clinically diagnosed interstitial pneumonia to investigate the factors which contribute to the difference in prognosis from the initiation of long-term oxygen therapy (LTOT) among subtypes. METHODS: Seventy-six patients with clinically diagnosed idiopathic interstitial pneumonia (IIP; n = 49) or interstitial pneumonia associated with collagen vascular disease (CVD-IP; n = 27) in whom LTOT was initiated in our facility from January 1999 to December 2012 were analyzed. RESULTS: Patients with CVD-IP had significantly longer survival time from the initiation of LTOT than those with IIP with the median survival of 51.7 months versus 18.8 months, respectively. The 1-year survival rate was 92.4% for patients with CVD-IP versus 76.5% for those with IIP, and 2-year survival was 88.6 versus 36.0%, respectively. The patterns classified with high-resolution computed tomography (HRCT) were not associated with prognosis. The association between pulmonary hypertension and prognosis was unclear. In results of the multivariate Cox analysis which included factors demonstrating p < 0.1 in the univariate Cox analysis, male gender, low body mass index, and the absence of collagen vascular disease (CVD) were significantly associated with poor prognosis. CONCLUSIONS: After the initiation of LTOT, patients with IIP had poor prognosis regardless of the patterns classified with HRCT, while those with CVD-IP survived longer. Male gender, low body mass index, and the absence of CVD were the independent negative prognostic factors in patients with interstitial pneumonia receiving LTOT.