Mechanical ventilation of patients on long-term oxygen therapy with acute exacerbations of chronic obstructive pulmonary disease: prognosis and cost-utility analysis

Astract Objective: To analyze the prognosis and costs of mechanical ventilation in patients with exacerbations of chronic obstructive pulmonary disease (COPD) treated with long-term oxygen therapy. Design: A prospective cohort study. Follow-up at 1 and 5 years. Cost utility analysis. Setting: A medical-surgical intensive care unit (ICU) in a university hospital. Patients: 20 patients with previous COPD treated with long-term oxygen therapy and needing mechanical ventilation due to acute respiratory failure. Measurements and main results: Mortality in the ICU, in-hospital mortality (ICU plus ward), and mortality at 1 and 5 years, and factors associated with prognosis and cost–utility were assessed. The mean Acute Physiology and Chronic Health Evaluation II score was 20 (median 20 range 12–36). Cumulative mortality was 35 % in the ICU, 50 % in hospital, 75 % at 1 year, and 85 % at 5 years. Factors significantly associated with mortality in the ICU were low levels of albumin (p = 0.05) and sodium (p = 0.01) at admission. Patients who died in hospital and in the first year after discharge had a lower forced expiratory volume in 1 s (FEV₁) than survivors (p = 0.03 and p = 0.05, respectively). The cost per Quality Adjusted Life Year (QALY) was U. S. $ 26 283 and U. S. $ 44 602 in a “best” (cost/QALY calculated for the life expectancy in Spain) and a “worst case scenario” (cost/QALY calculated for a 68-year life expectancy), respectively. Conclusions: Applying mechanical ventilation to COPD patients treated with long-term oxygen therapy carries a high mortality and cost. Factors significantly associated with mortality in the ICU were albumin and sodium concentrations and FEV₁ in hospital and in the first year after discharge. Received: 4 August 1998 Final revision received: 28 January 1999 Accepted: 3 February 1999