TABLE 1

Total cohort patient characteristics and blood pressure measurements stratified by obstructive sleep apnoea (OSA) severity quartiles

VariableTotal cohortQuartile 1Quartile 2Quartile 3Quartile 4p-value
Subjects n6516171616
Age years41±738±640±842±843±70.158
BMI kg·m−233.5±5.830.1±3.730.9±2.634.8±5.0#38.5±6.9#,¶<0.001
Neck circumference cm43±341±343±244±3#45±3#0.004
Waist–hip ratio1.00±0.060.98±0.071.00±0.061.00±0.041.04±0.050.115
Smoking pack-years9±129±78±1313±147±100.566
Current smokers %20251825130.862
Clinic systolic BP137±11136±14136±11140±12138±80.706
Clinic diastolic BP83±883±981±784±986±70.458
ESS score11±510±712±512±512±50.885
HBA1c37±336±235±336±339±3#,¶,+0.004
HOMA3.7±2.92.2±1.13.3±1.93.2±1.96.0±4.1#,¶,+0.001
Total cholesterol4.9±0.85.1±0.84.8±0.75.0±0.94.8±1.00.652
Triglycerides1.6±0.81.5±0.91.5±0.71.9±1.01.5±0.80.362
HDL1.1±0.31.1±0.31.2±0.31.1±0.31.1±0.30.851
LDL3.1±0.73.3±0.63.0±0.73.1±0.73.0±0.90.528
Creatinine84±1289±1485±1484±1179±80.110
eGFR97±1395±1597±1496±10102±110.400
AHI events·h−113.6 (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−112.2 (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−18.3 (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.