Table 5.
Studies investigating changes in weight and glycemic control following PAP treatment.
| References | Study design | Number of patients | Patients with pathological glucose tolerance | PAP duration | Results |
|---|---|---|---|---|---|
| Ou et al. (37) | RCT (PAP + standard care vs. standard care) | 2,483 | 30% (DM) | 3.8 ± 1.5 years | (i) No difference in weight change between the PAP and control group, in male and female subjects. (ii) Male participants who used PAP ≥ 4 h/night gained slightly more weight than matched male control subjects without PAP. |
| Barbé et al. (36) | RCT (PAP vs. no active intervention) | 723 | not given | 4 (2.7; 4.4) years | (i) BMI decreased significantly in the control group compared to the PAP group. (ii) There was no change in BMI in the PAP group. |
| Loffler et al. (40) | Randomized clinical trial (CPAP + usual care vs. usual care alone) | 888 | 31% (DM2) 51% (prediabetes) |
4.3 years (range 16 days−6.9 years) | (i) In those with preexisting diabetes and prediabetes, there was no significant difference in HbA1c between the PAP and usual care groups. (ii) In participants with preexisting diabetes who were not using insulin, there was a small increase in HbA1c in PAP users. |
| Guest et al. (41) | Case-control | 300 | 100% (DM2) | 5 years | (i) At baseline, there was no difference in HbA1c between DM2 patients with and without PAP (7.5 vs. 7.4%) (ii) PAP treated patients had a significant lower HbA1c at 5 years follow-up than untreated patients (8.2 vs. 12.1%). |
| Myllylä et al. (38) | Retrospective | 1,023 | 40% (DM2/impaired fasting glucose) | 6.6 ± 1.2 years | (i) 84% of OSA patients had no significant weight change during PAP treatment. (ii) In 10% of OSA patients significant weight gain was observed. |
| Basoglu et al. (39) | Observational | 1,415 | 15% (DM2) | 1.1 ± 1.0 years | (i) PAP is not associated with a significant weight change in OSA patients. (ii) In non-obese patients (BMI <30 kg/m2), weight and BMI increased after PAP. (iii) In obese patients (BMI ≥ 30 kg/m2), weight and BMI were reduced after PAP. |
| Malik et al. (42) | Observational | 62 | 100% (DM2) | 12 months | (i) 59% of the DM2 patients showed a decline in HbA1c with PAP treatment. (ii) 7% of DM2 Patients showed a significant improvement in HbA1c with PAP. |
| Schaller et al. this issue | Observational | 346 | 100% (DM2) | 1.6 (1.2;2.2) years | (i) PAP is not associated with a significant median weight change. (ii) HbA1c increased significantly in patients with PAP treatment compared to untreated patients. (iii) PAP is associated with an increased odds ratio for a severe weight gain ≥ 5 kg and an increase in HbA1c. |
BMI, body-mass index; DM2, type 2 diabetes mellitus; HbA1c, hemoglobin A1c; OSA, obstructive sleep apnea; PAP, positive airway pressure; RCT, randomized controlled trial.