Baseline characteristics of trials included in meta-analysis
| Study | OSA definition (events·h−1) | Intervention | Subjects (n) | Follow-up (weeks) | Age (years) | Male (%) | BMI (kg·m−2) | HbA1c (%) | CPAP usage (h·night−1) | AHI (events·h−1) | Duration DMII (years) | Outcomes |
| Banghøj et al., 2020 [19] | AHI ≥15 | CPAP No CPAP | 72 | 12 | 62±7.5 | 75 | 34.6±4.2 | 8.0±0.8 8.1±0.8 | 5.6±1.9 | 32.0 (21–43) 34.0 (22–49) | 16±8.6 | HbA1c, FBG, 24 h glucose |
| Bakker et al., 2020 [27] | AHI ≥10 | CPAP Sham CPAP | 53 | 12 | 56.2±9.3 | 64 | 35.4±6.8 | 6.7±0.5 7.1±0.6 | 4.3±2.4 | 23.5±15.1 | NA | HbA1c, FBG |
| Chasens et al., 2022 [16] | AHI ≥10 | CPAP Sham CPAP | 98 | 6 | 58.7±9.8 | 58 | 36.2±6.6 | 7.7±0.8 8.0±1.0 | 5.0±1.7 4.4±2.1 | 22.5±13.4 25.9±15.9 | 10±9.0 | HbA1c, fructosamine |
| Lam et al., 2017 [23] | AHI ≥15 | CPAP No CPAP | 64 | 12 | 55±9.0 | 81 | 29.9±5.3 | 8.0±1.2 8.3±1.4 | 2.5±2.3 | 43.4±23.1 47.2±23.5 | 9±5.9 | HbA1c, FBG, fructosamine |
| Martínez-Cerón et al., 2016 [15] | AHI ≥5 | CPAP No CPAP | 50 | 12 | 61±9.0 | 60 | 32.5±4.5 | 7.6±1.3 7.6±0.7 | 5.2±1.9 | 35.6±23.4 28.2±17.4 | 5 (3.0–15.0) | HbA1c, FBG, HOMA-IR |
| Mokhlesi et al., 2016 [24] | AHI ≥15 | CPAP Sham CPAP | 19 | 1 | 55±3.3 | 47 | 37.8±2.8 | 7.3±0.4 7.0±0.4 | 7.9±0.1 7.9±0.1 | NA | 4±2.8 | 24 h glucose |
| Morariu et al., 2017 [25] | AHI ≥10 | CPAP Sham CPAP | 23 | 4 | 55.6±11.6 | 51 | 35.2±5.3 | 6.6±0.5 6.9±1.0 | 4.1±2.9 4.5±2.7 | 56.6±29.8 25.6±11.4 | NA | 24 h glucose, fructosamine |
| Shaw et al., 2016 [13] | AHI ≥15 | CPAP No CPAP | 298 | 24 | 62.3±9.0 | 65 | 33.0±5.4 | 7.3±0.5 7.3±0.5 | 4.9±NA | 26.2±12.9 28.0±14.1 | 8±6.9 | HbA1c, FBG, |
| West et al., 2007 [26] | ODI ≥10 | CPAP Sham CPAP | 42 | 12 | 56.1±9.9 | 100 | 36.7±4.7 | 8.5±1.8 8.6±1.7 | 3.6±2.8 3.3±3.0 | NA | NA | HbA1c, FBG, HOMA-IR |
| Zamarron et al., 2022 [17] | AHI ≥10 | CPAP No CPAP | 185 | 52 | 67±9.0 | 76 | 32.0±5.1 | 7.7±1.6 7.5±1.4 | 4.1±2.9 | 37.0±20.0 33.9±18.7 | 16±9.5 | HbA1c, FBG, HOMA-IR, |
| Zhao et al., 2022 [18] | AHI ≥5 | CPAP No CPAP | 60 | 6 | 53.4±10.2 | 58 | 30.5±4.0 | 8.5±2.3 8.7±1.7 | 8.3±2.8 | 28.3±17.8 34.5±20.4 | 7±6.5 | HbA1c, FBG, HOMA-IR |
Values are presented as mean±sd or median (interquartile range) unless otherwise stated. OSA: obstructive sleep apnoea; BMI: body mass index; HbA1c: haemoglobin A1c; CPAP: continuous positive airway pressure; AHI: apnoea–hypopnoea index; DMII: type 2 diabetes; FBG: fasting blood glucose; ODI: oxygen desaturation index; NA: not available; HOMA-IR: homeostasis model of assessment for insulin resistance index.