Prognostic factors for survival related to noninvasive ventilation (NIV) failure: univariate analysis
| Factor (mean) | HR (95% CI) | p-value |
| Age (64.08 years) | 1.01 (0.98–1.03) | 0.600 |
| Male sex | 1.43 (0.91–2.24) | 0.114 |
| Bulbar onset | 2.13 (1.35–3.36) | 0.001 |
| Time from ALS onset to NIV (22.60 months) | 0.99 (0.97–1.01) | 0.320 |
| BMI (26.06 kg·m−2) | 0.95 (0.89–1.01) | 0.070 |
| FVC (1.48 L) | 0.51 (0.36–0.72) | 0.001 |
| FVC % predicted (49.33%) | 0.98 (0.97–0.99) | 0.001 |
| MIC (1.91 L) | 0.58 (0.43–0.78) | 0.001 |
| PCF (3.55 L·s−1) | 0.73 (0.62–0.86) | 0.001 |
| PCFMIC (4.13 L·s−1) | 0.77 (0.67–0.89) | 0.001 |
| PCFMI-E (3.73 L·s−1) | 0.71 (0.56–0.90) | 0.005 |
| PImax (−44.73 cmH2O) | 1.01 (1.00–1.02) | 0.018 |
| PEmax (66.37 cmH2O) | 0.99 (0.98–1.00) | 0.040 |
| ALSFRS-R (20.01) | 0.95 (0.92–0.98) | 0.002 |
| NBS (26.67) | 0.95 (0.93–0.97) | 0.001 |
| PaO2 under NIV (83.13 mmHg) | 0.98 (0.97–1.01) | 0.286 |
| PaCO2 under NIV (42.12 mmHg) | 1.04 (0.99–1.09) | 0.134 |
| %sleepSpO2<90 under NIV (1.20%) | 1.11 (1.04–1.19) | 0.002 |
HR: hazard ratio; ALS: amyotrophic lateral sclerosis; BMI: body mass index; FVC: forced vital capacity; MIC: maximum insufflation capacity; PCF: peak cough flow; PCFMIC: manually assisted peak cough flow; PCFMI-E: mechanically assisted peak cough flow; PImax: maximum inspiratory pressure; PEmax: maximum expiratory pressure; ALSFRS-R: revised amyotrophic lateral sclerosis functional rating scale; NBS: Norris scale bulbar subscore; PaO2: arterial oxygen tension; PaCO2: arterial carbon dioxide tension; %sleepSpO2<90: time spent with oxygen saturation measured by pulse oximetry <90%.