Predictors of first-year survival in patients with advanced COPD treated using long-term oxygen therapy

Abstract

Little evidence-based guidance is available to aid clinicians in determining short-term prognoses in very severe COPD patients. Therefore, the present study was designed to provide a prospective assessment (1) of the mortality rates and (2) whether the baseline measurements may be determinants of 1-year mortality in hypoxemic COPD patients receiving long-term oxygen therapy (LTOT). Seventy-eight clinically stable patients with advanced COPD treated using LTOT were enrolled in a prospective cohort study.

Outcome variable: first-year mortality. Baseline measurements: categorical variables: age (<60 or > or = 60 years); gender; body mass index (<20 or > or = 20 kg/m(2)); fat-free mass (FFM) index (<16 [men] and <15 kg/m(2) [women]; baseline dyspnea index (BDI) (< or = 3 or >3); and corticosteroid use. Continuous variables: smoking history; lung function; FFM; fat mass; hemoglobin; hematocrit; arterial blood gases; forearm muscle strength; St. George's Respiratory Questionnaire (SGRQ); and comorbidity score. By the end of 1-year of follow-up, 12 patients (15.4%) had died. Kaplan-Meier curves showed that BDI < or = 3 was the only variable associated with higher mortality. Cox proportional hazards analysis revealed that lower PaO(2) and SpO(2), higher PaCO(2) and SGRQ scores were associated with reduced survival. In the multivariate analysis, BDI remained predictive of mortality (hazard ratio [HR], 0.50; 95% confidence interval [CI], 0.31-0.81), as did PaO(2) (HR, 0.49; 95% CI, 0.26-0.95). These data suggest that readily available parameters as dyspnea intensity and hypoxemia severity may be useful in predicting first-year survival rates in advanced COPD patients receiving LTOT.