TABLE 3.
Summary of effects of continuous positive airway pressure (CPAP) on energy expenditure via indirect calorimetry in obstructive sleep apnoea (OSA) patients
| First author [ref.] | Year | Participants | AHI cut-off events·h−1 |
Sample size | Age years | Baseline BMI kg·m−2 |
Baseline ESS | Design | CPAP duration |
CPAP compliance h per night |
Outcomes | Main findings: effect of CPAP |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fekete [65] | 2015 | OSA-CPAP | ≥15# | 62 | 46.5±11.4 | 33.9±5.2 | 13.0±6.1 | Between groups | 1 day | N/R | REE using indirect calorimetry, pre-sleep and after awakening | ↑ REE and REE/ LBM in OSA-CPAP versus control |
| Control | N/R | 19 | 50.8±11.7 | 28.3±3.1 | 8.5±3.4 | |||||||
| Ryan [66] | 1995 | OSA | >30 | 10 | 45.0±10.0¶ | 39.8±6.5¶ | N/R | Baseline to post-treatment | 3 months | 5.0±1.0 | REE using indirect calorimetry, a. m., fasted; TEF after liquid test meal | ↔ REE after treatment ↔ TEF after treatment |
| Shechter [68] | 2015 | OSA | x̄ = 28 | 3 | 50.7±4.5 | 32.1±1.4 | 10.0±1.7 | Sham-controlled, crossover | 2 months | N/R | WRIC for 24-h energy expenditure and sleeping energy expenditure | ↑ mean daily energy expenditure and sleeping energy expenditure in active versus sham |
| Smurra [67] | 2001 | OSA | x̄ = 31 | 10 | 49.2±8.7 | 33.0±3.8 | N/R | Baseline to post-treatment | 2 months | 6.4±0.8 | Indirect calorimetry for basal energy expenditure | ↔ basal energy expenditure after treatment |
| Stenlof [26] | 1996 | OSA | ≥20+ | 5 | 46.0±13.0 | 34.0±7.0 | N/R | Baseline to post-treatment | 3 months | N/R | WRIC for 24 h energy expenditure; BMR in a.m., fasted; SMR | ↓ SMR/FFM after treatment ↔ BMR or 24 h energy expenditure |
| Tachikawa [48] | 2016 | OSA | >20 | 63 | 60.6±10.0 | 27.9±3.8 | 8.7±5.3 | Baseline to post-treatment | 1 day; 3 months | 4.5±1.6 | Indirect calorimetry for BMR in a.m., fasted | ↓ BMR after 3 months but not 1 day |
Data are presented as n or mean±SD, unless otherwise stated. AHI: apnoea–hypopnoea index; BMI: body mass index; ESS: Epworth sleepiness scale; N/R: not reported; REE: resting energy expenditure; LBM: lean body mass; TEF: thermic effect of food; WRIC: whole-room indirect calorimetry; SMR: sleeping metabolic rate; FFM: fat-free mass; BMR: basal metabolic rate. ↑: significant increase; ↓: significant decrease; ↔: no difference.
included AHI ≥15 with no symptoms or ≥5 with symptoms (daytime sleepiness, poor sleep or snoring/gasping);
full OSA group at baseline, not just CPAP.
cut-off based on respiratory disturbance index, not AHI.