First author [Ref.] | Bilevel NIPPV | Control | Weight % | WMD (random) 95% CI | ||

n | Mean±sd | n | Mean±sd | |||

Clini 23 | 38 | 50.60±20.60 | 46 | 48.10±27.70 | 77.00 | 2.50 (−7.73–12.73) |

Renston 22 | 9 | 48.00±19.50 | 8 | 37.00±19.80 | 23.00 | 11.00 (−7.72–29.72) |

Total | 47 | 54 | 100 | 4.45 (−4.52–13.43) |

NIPPV: noninvasive positive pressure ventilation; WMD: weighted mean difference; CI: confidence interval. Comparison: RCT trials of bilevel NIPPV

*versus*all modalities (long-term oxygen therapy, sham ventilation, exercise). Outcome: MIP cmH_{2}O. Test for heterogeneity: Chi squared = 0.61, df = 1 (p = 0.43), I^{2}= 0%. Test for overall effect: Z = 0.97 (p = 0.33).