TABLE 1.
Total cohort patient characteristics and blood pressure measurements stratified by obstructive sleep apnoea (OSA) severity quartiles
| Variable | Total cohort | Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | p-value |
| Subjects n | 65 | 16 | 17 | 16 | 16 | |
| Age years | 41±7 | 38±6 | 40±8 | 42±8 | 43±7 | 0.158 |
| BMI kg·m−2 | 33.5±5.8 | 30.1±3.7 | 30.9±2.6 | 34.8±5.0# | 38.5±6.9#,¶ | <0.001 |
| Neck circumference cm | 43±3 | 41±3 | 43±2 | 44±3# | 45±3# | 0.004 |
| Waist–hip ratio | 1.00±0.06 | 0.98±0.07 | 1.00±0.06 | 1.00±0.04 | 1.04±0.05 | 0.115 |
| Smoking pack-years | 9±12 | 9±7 | 8±13 | 13±14 | 7±10 | 0.566 |
| Current smokers % | 20 | 25 | 18 | 25 | 13 | 0.862 |
| Clinic systolic BP | 137±11 | 136±14 | 136±11 | 140±12 | 138±8 | 0.706 |
| Clinic diastolic BP | 83±8 | 83±9 | 81±7 | 84±9 | 86±7 | 0.458 |
| ESS score | 11±5 | 10±7 | 12±5 | 12±5 | 12±5 | 0.885 |
| HBA1c | 37±3 | 36±2 | 35±3 | 36±3 | 39±3#,¶,+ | 0.004 |
| HOMA | 3.7±2.9 | 2.2±1.1 | 3.3±1.9 | 3.2±1.9 | 6.0±4.1#,¶,+ | 0.001 |
| Total cholesterol | 4.9±0.8 | 5.1±0.8 | 4.8±0.7 | 5.0±0.9 | 4.8±1.0 | 0.652 |
| Triglycerides | 1.6±0.8 | 1.5±0.9 | 1.5±0.7 | 1.9±1.0 | 1.5±0.8 | 0.362 |
| HDL | 1.1±0.3 | 1.1±0.3 | 1.2±0.3 | 1.1±0.3 | 1.1±0.3 | 0.851 |
| LDL | 3.1±0.7 | 3.3±0.6 | 3.0±0.7 | 3.1±0.7 | 3.0±0.9 | 0.528 |
| Creatinine | 84±12 | 89±14 | 85±14 | 84±11 | 79±8 | 0.110 |
| eGFR | 97±13 | 95±15 | 97±14 | 96±10 | 102±11 | 0.400 |
| AHI events·h−1 | 13.6 (4.7–26.2) | 1.3 (0.6–3.4) | 7.7 (5.6–14.7) | 19.7 (17.0–24.6)# | 45.0 (33.5–75.6)#,¶,+ | <0.001 |
| ODI events·h−1 | 12.2 (3.9–25.1) | 1.8 (0.6–2.3) | 6.4 (5.5–7.8) | 17.2 (14.6–20.3)# | 44.9 (26.6–62.5)#,¶,+ | <0.001 |
| TST90 % | 0.6 (0.0–5.6) | 0.0 (0–0.2) | 0.1 (0–1.3) | 2.2 (0.2–4.9) | 19.8 (3.8–54.6)#,¶,+ | <0.001 |
| Minimum SpO2 % | 87 (79–89) | 89 (88–91) | 88 (85–90) | 83 (78–87)# | 72 (67–84)#,¶,+ | <0.001 |
| Arousal index events·h−1 | 8.3 (5.2–16.4) | 5.6 (3.8–7.1) | 9.0 (5.6–14.7) | 9.1 (4.5–12.7) | 18.9 (7.0–31.7)#,¶,+ | 0.001 |
Values represent mean±sd or median (interquartile range) depending on distribution. BMI: body mass index; BP: blood pressure; ESS: Epworth Sleepiness Scale; HbA1c: glycosylated haemoglobin (mmol·mol−1); HOMA: homeostasis model assessment; HDL: high-density lipoprotein; LDL: low-density lipoprotein; eGRF: estimated glomerular filtration rate; AHI: apnoea–hypopnoea index; ODI: oxygen desaturation index; TST90: total sleep time with O2 saturations <90%; SpO2: oxygen saturation measured by pulse oximetry. #p<0.05 versus AHI quartile 1; ¶p<0.05 versus AHI quartile 2; +p<0.05 versus AHI quartile 3.