[Home days ratio in patients treated with long-term oxygen therapy]

The home days ratio (days at home/observation period) is an important index for evaluating the efficacy of therapy for chronic disease. To compute the home days ratio in patients treated with long-term oxygen therapy, we retrospectively studied the records of 72 consecutive patients with chronic respiratory failure who received long-term oxygen therapy from the Department of Pulmonary Medicine, Ogaki Municipal Hospital. These patients were representative of those treated with long-term oxygen therapy in terms of age, cause of hypoxemia, blood gas values, and pulmonary function. The home days ratio gradually decreased; it was 92.7 +/- 15.2% during the first year, 87.5 +/- 24.0% during the second year, and 78.5 +/- 39.7% during the third year. The home days ratios in survivors (n = 39) were greater than in non-survivors (n = 33). For the first year: 96.7 +/- 7.5% vs. 85.8 +/- 21.9%, p = 0.034; for the second year: 99.0 +/- 2.6% vs. 71.4 +/- 31.0%, p = 0.004; for the third year: 96.0 +/- 9.0% vs. 48.4 +/- 53.1%, p = 0.081, for survivors and non-survivors, respectively. These data suggest that non-survivors can be distinguished from survivors soon after the start of oxygen therapy.