Predictive significance of the six-minute walk distance for long-term survival in chronic hypercapnic respiratory failure

Background: The 6-min walk distance ( 6-MWD) is a global marker of
functional capacity and prognosis in chronic obstructive pulmonary
disease ( COPD), but less explored in other chronic respiratory
diseases. Objective: To study the role of 6-MWD in chronic
hypercapnic respiratory failure ( CHRF). Methods: In 424 stable
patients with CHRF and non-invasive ventilation ( NIV) comprising
COPD ( n = 197), restrictive diseases ( RD; n = 112) and
obesity-hypoventilation- syndrome ( OHS; n = 115), the prognostic
value of 6-MWD for long- term survival was assessed in relation to
that of body mass index (BMI), lung function, respiratory muscle
function and laboratory parameters. Results: 6-MWD was reduced in
patients with COPD ( median 280 m; quartiles 204/350 m) and RD (
290 m; 204/362 m) compared to OHS ( 360 m; 275/440 m; p