Clinical features of patients with obesity hypoventilation syndrome based on an aggregated sample of 757 patients from 15 studies
| Clinical features | Mean (range) |
| Age years | 52 (42–61) |
| Male % | 60 (49–90) |
| Body mass index kg·m−2 | 44 (35–56) |
| Neck circumference cm | 46.5 (45–47) |
| pH | 7.38 (7.34–7.40) |
| Arterial PCO2 mmHg | 53 (47–61) |
| Arterial PO2 mmHg | 56 (46–74) |
| Serum bicarbonate mEq·L−1 | 32 (31–33) |
| Haemoglobin g·dL−1 | 15 |
| Apnoea–hypopnoea index | 66 (20–100) |
| SpO2 nadir during sleep % | 65 (59–76) |
| Per cent sleep time SpO2 <90% | 50 (46–56) |
| FVC % predicted | 68 (57–102) |
| FEV1 % predicted | 64 (53–92) |
| FEV1/FVC | 0.77 (0.74–0.88) |
| Medical Research Council Dyspnoea class 3 or 4 % | 69 |
| Epworth sleepiness scale score | 14 (12–16) |
PCO2: carbon dioxide tension; PO2: oxygen tension; SpO2: arterial oxygen saturation measured by pulse oximetry; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s. Reproduced from [1] with permission from the publisher.