Table 3.
OSA, CPAP, and glucose homeostasis
| Outcome measure | Studies with positive effect reported | Studies with no effect reported |
|---|---|---|
| Fasting plasma glucose | ||
| Number of studies | 3 [42, 71, 142] | 23 [4, 20, 24, 26, 30, 31, 55, 76, 87, 88, 93, 109, 110, 118, 121, 156, 169, 171, 181, 185, 199, 206] |
| Number of subjects | 67 (32 metabolic syndrome) | 700 (44 type 2 diabetes, 16 metabolic syndrome) |
| CPAP use | ≤4–5.3 h/night | 3.3 h–6.2 h |
| Duration of CPAP treatment | 4 days–2.9 years | 1 week–39 months |
| Fasting serum insulin | ||
| Number of studies | 3 [42, 71, 93] | 19 [4, 24, 26, 29–31, 55, 76, 88, 109, 110, 118, 138, 156, 169, 171, 185, 199, 206] |
| Number of subjects | 75 (5 type 2 diabetes, 32 metabolic syndrome) | 484 (44 type 2 diabetes) |
| CPAP use | ≤4–5.3 h/night | 3.3–5.6 h/night |
| Duration of CPAP treatment | 3 weeks–3 months | 1 week–>6 months |
| Improved glucose tolerancea | ||
| Number of studies | 7 [4, 24, 68, 71, 118, 169, 205] | 6[15, 55, 87, 110, 142, 156] |
| Number of subjects | 276 (136 type 2 diabetes) | 100 (10 type 2 diabetes, 11 children with metabolic syndrome) |
| CPAP use | ≤4–5.3 h/night | ≤4–6.4 h/night |
| Duration of CPAP treatment | 4 days–>6 months | 2 months–2.9 years |
| Improved insulin sensitivityb | ||
| Number of studies | 12 [15, 24, 36, 42, 65, 71, 88, 118, 142, 180, 205] | 18[20, 26, 29–31, 55, 76, 93, 109, 110, 138, 156, 169, 171, 181, 185, 199, 206] |
| Number of subjects | 246(35 type 2 diabetes, 32 metabolic syndrome) | 435(19 type 2 diabetes, 11 children with metabolic syndrome) |
| CPAP use | ≤4–6.2 h | ≤4–5.7 h/night |
| Duration of CPAP treatment | 1 week–2.9 years | 3 weeks–6 months |
| Improved beta-cell functionc | ||
| Number of studies | 1 [31] | 3[71, 109, 180] |
| Number of subjects | 31 | 102 |
| CPAP use | n.a. | ≤4–6.2 h/night |
| Duration of CPAP treatment | 2 months | 1–3 months |
HOMA-IR=[fasting plasma glucose (mmol/l)×fasting serum insulin (mIU/l)/22.5]; QUICKI quantitative insulin sensitivity check index=1/[log insulin ratio (mU/L)+log baseline glucose (mg/dl)]
Improved glucose tolerance was defined as decreased glucose levels at OGTT, or decreased HbA1c, or lower 24-h glucose concentrations at CGMS, after CPAP treatment
Improved insulin sensitivity was defined as increased insulin responsiveness index (M) or insulin sensitivity index (ISI) at HEC, or increased SI at ivGTT, or increase of Kitt at short insulin test, or increased whole body insulin sensitivity index at OGTT, or decreased HOMA-IR, or increased QUICKI, or decreased insulin/glucose ratio, after CPAP treatment
Improved beta-cell function was defined as increased AIRg at IVGTT or increased HOMA-beta, after CPAP treatment
OGTT Oral glucose tolerance test, HbA1c glycosylated hemoglobin, HEC hyperinsulinemic euglycemic clamp, CGMS continous glucose monitoring system, SI insulin sensitivity, ivGTT intravenous glucose tolerance test, Kitt glucose disappearance rate constant, AIRg acute insulin response to glucose