Health status predicted mortality in hypercapnic patients with noninvasive ventilation

Introduction: Although health status and mortality are important outcomes in patients with advanced pulmonary diseases receiving noninvasive ventilation (NIV), their relationship has not been thoroughly investigated. Hypothesis: We hypothesized that health status assessment using questionnaires specific for chronic respiratory failure would predict mortality in patients receiving NIV. Methods: We prospectively recruited 56 stable outpatients treated with NIV for chronic hypercapnic respiratory failure caused by chronic obstructive pulmonary disease and/or pulmonary tuberculosis sequelae. Arterial blood gas, pulmonary function and health status using four different questionnaires, dyspnea and psychological status were measured at baseline. Results: In cross-sectional comparisons of four health status questionnaires, the Severe Respiratory Insufficiency (SRI) questionnaire had the lowest floor and ceiling effects. During the three-year follow-up, 16 patients (29%) died. Univariate analysis revealed that low body mass index (BMI), high arterial carbon dioxide pressure, low forced vital capacity, low health status, and severe dyspnea and depression were significantly related to mortality. Stepwise multivariate analyses indicated that SRI summary was the most significant predictor of mortality, followed by BMI. Conclusion: Health status was significantly related to three-year mortality independently of under-nutrition, hypercapnia and low pulmonary function in hypercapnic patients with severe respiratory insufficiency receiving NIV. SRI was more significantly related with mortality than other health status questionnaires, and had a balanced score distribution.