Impact of noninvasive home ventilation on long-term survival in chronic hypercapnic COPD: a prospective observational...

The long-term benefit from noninvasive ventilation (NIV) in chronic hypercapnic chronic obstructive pulmonary disease (COPD) remains uncertain.

Within a prospective observational design, we compared the long-term survival of 140 patients with severe persistent hypercapnic COPD (FEV(1) 28.7 +/- 8.7% predicted; PaCO(2) 60.1 +/- 9.2 mmHg) with (n = 99) or without (n = 41) NIV. End-point was all-cause mortality, determined up to 4 years by Kaplan-Meier analysis. Additionally, Cox's proportional hazards regression and stratification by risk factors was performed. Patients were characterised by anthropometric and functional parameters, comorbidities and medical therapy.

Adherence in patients with NIV was high (88.9%), daily ventilator use being 6.4 +/- 2.6 h/day and inspiratory pressures 21.0 +/- 4.0 cmH(2)O. One- and 2-year survival rates were 87.7% and 71.8%, respectively, in patients with NIV vs. 56.7% and 42.0% in patients without NIV. Survival rates were significantly higher in patients with NIV compared to those without this therapy (p = 0.001; hazard ratio 0.380; 95% confidence interval 0.138-0.606). The difference between groups was still significant after adjustment for differences in baseline characteristics. Moreover, stratification by risk factors revealed beneficial effects, particularly in patients with high base excess (BE; > 8.9 mmol/l), low pH (< 7.41), FEV(1) (< 27.5%) haemoglobin (< 13.8 g/dl) or large hyperinflation (residual volume-to-total lung capacity > 189% predicted) upon inclusion (p < 0.05 each).

In patients with severe chronic hypercapnic COPD receiving NIV at high inspiratory pressure levels and showing high adherence to this therapy, long-term survival was significantly higher than in non-ventilated patients. Patients displaying more severe disease according to known risk factors seemed to benefit most from long-term NIV.