Table 2.
Comparison of sleep characteristic and biochemical parameters between the OSA subgroups.
| Non OSA or mild OSA | Moderate OSA | Severe OSA | p value | |
|---|---|---|---|---|
| Epworth sleepiness scale | 6 (4–7) | 6 (3–8) | 8 (5–11) | 0.001 |
| AHI (/h) | 11.8 (7.6–13.6) | 21.7 (17.2–25.5) | 46.9 (37.6–59.9) | < 0.001 |
| Desaturation index (/h) | 12.0 (8.0–14.1) | 23.1 (18.4–26.9) | 47.7 (37.6–59.7) | < 0.001 |
| tSaO2 < 90% (%) | 9 (2–43) | 19 (6–49) | 37 (14–60) | 0.001 |
| Mean nocturnal SaO2 (%) | 92 (90–93) | 91 (90–92) | 90 (88–92) | 0.019 |
| Low nocturnal SaO2 (%) | 83 (79–86) | 80 (74–83) | 74 (65–79) | < 0.001 |
| Apnea index (/h) | 1.8 (0.6–3.0) | 5.5 (2.9–9.7) | 17.3 (10.7–30.9) | < 0.001 |
| Hypopnea index (/h) | 9.2 (5.6–11.1) | 15.6 (10.8–19.4) | 24.8 (17.7–32.6) | < 0.001 |
| Obstructive apnea index (/h) | 1.5 (0.3–3.0) | 4.6 (2.3–9.0) | 12.8 (6.8–23.8) | < 0.001 |
| Central apnea index (/h) | 0 (0–0.2) | 0.5 (0–1.0) | 0.8 (0–4.5) | < 0.001 |
| Urinary albumin–creatinine ratio (mg/g) | 57.6 (35.1–96.4) | 110.3 (53.0–217.9) | 651.9 (259.6–1242.8) | < 0.001 |
| eGFR (ml/min per 1.73 m2) | 71.9 (57.0–90.0) | 56.0 (41.8–69.3) | 42.0 (31.6–58.5) | < 0.001 |
| Serum creatinine (mg/dl) | 1.4 ± 0.5 | 1.3 ± 0.5 | 1.6 ± 0.8# | 0.007 |
| Fasting glucose (mg/dl) | 137 (113–179) | 144 (113–185) | 150 (123–180) | 0.653 |
| HbA1c (%) | 7.4 ± 1.5 | 7.8 ± 1.8 | 7.6 ± 1.4 | 0.470 |
| HbA1c (mmol/mol) | 57.1 ± 16.4 | 61.3 ± 19.9 | 59.9 ± 15.2 | 0.470 |
| HOMA-IR indexa | 4.59 (1.73–7.83) | 3.30 (2.42–6.20) | 5.36 (2.92–8.54) | 0.405 |
| QUICKI indexa | 0.31 (0.29–0.35) | 0.32 (0.29–0.33) | 0.30 (0.28–0.33) | 0.405 |
| hsCRP (mg/l) | 0.80 (0.20–3.30) | 1.80 (0.40–4.15) | 2.75 (0.70–6.10) | 0.103 |
| Total cholesterol (mg/dl) | 152 ± 33 | 157 ± 41 | 149 ± 36 | 0.386 |
| HDLc (mg/dl) | 40 ± 10 | 42 ± 12 | 40 ± 13 | 0.461 |
| LDLc (mg/dl) | 85 ± 27 | 83 ± 39 | 80 ± 30 | 0.701 |
| Triglycerides (mg/dl) | 152 ± 76 | 184 ± 114 | 153 ± 66 | 0.051 |
Values are median (interquartile range [IQR]) or mean ± SD, according their distribution. Comparisons were performed by Kruskal–Wallis test or ANOVA with post-hoc comparisons by Bonferroni test: #p < 0.01 vs. moderate OSA.
AHI apnea–hypopnea index, tSaO2 percentage of recording time with oxygen saturation < 90%, SaO2 oxygen saturation, eGFR estimated glomerular filtration rate, HbA1c glycated hemoglobin, HOMA-IR Homeostasis Model Assessment-Insulin Resistance (HOMA-IR), QUICKI Qualitative Insulin Sensitivity Check Index, hsCRP high-sensitivity C reactive protein, HDL high-density lipoprotein cholesterol, LDL-c low-density lipoprotein cholesterol.
aOnly in noninsulin user patients (n = 78).