Characteristics of patients in moderate–severe OSA by clusters (n=1108)
| Variables | Cluster 1 (n=333, 30%) | Cluster 2 (n=265, 24%) | Cluster 3 (n=271, 24%) | Cluster 4 (n=239, 22%) | P for difference* |
| Demographics | |||||
| Male, n (%) | 258 (77.5%) | 168 (63.4%) | 224 (82.7%) | 177 (74.1%) | <0.001 |
| Age, year | 49.6 (12.2) | 55.6 (11.5) | 52.5 (12.0) | 58.0 (11.2) | <0.001 |
| Symptom and measurements | |||||
| BMI, kg/m2 | 34.7 (5.4) | 25.1 (2.8) | 30.0 (2.3) | 25.5 (2.3) | <0.001 |
| Neck circumference, cm | 42.8 (4.2) | 36.9 (2.7) | 40.8 (2.3) | 37.5 (2.3) | <0.001 |
| Waist circumference, cm | 108.7 (12.0) | 87.4 (6.8) | 100.1 (5.4) | 88.2 (5.7) | <0.001 |
| Polysomnogram | |||||
| AHI, /hour | 68.2 (53.7–82.3) | 23.1 (18.8–28.4) | 35.3 (25.4–46.5) | 49.2 (37.8–61.0) | <0.001 |
| TST90, min | 111.3 (50.3–200.6) | 3.8 (1.4–8.0) | 15.6 (6.8–27.5) | 40.4 (21.7–68.0) | <0.001 |
| Mean heart rate, /min | 69.0 (63.1–75.0) | 62.5 (57.5–68.3) | 63.6 (57.5–70.5) | 64.0 (58.9–70.7) | <0.001 |
| History | |||||
| Prior hypertension, n (%) | 262 (78.7%) | 157 (59.2%) | 202 (74.5%) | 168 (70.3%) | <0.001 |
| Prior diabetes, n (%) | 113 (33.9%) | 76 (28.7%) | 91 (33.6%) | 69 (28.9%) | 0.362 |
| Prior CVDs*, n (%) | 62 (18.6%) | 26 (9.8%) | 46 (17.0%) | 34 (14.2%) | 0.020 |
| Cigarette smoking, n (%) | <0.001 | ||||
| No | 229 (73.4%) | 200 (74.3%) | 160 (74.1%) | 241 (59.4%) | |
| Former | 41 (13.1%) | 26 (9.7%) | 23 (10.6%) | 77 (19.0%) | |
| Current | 42 (17.1%) | 43 (14.3%) | 33 (17.0%) | 88 (18.0%) | |
| Regular CPAP use, n (%) | 100 (30.0%) | 43 (16.2%) | 54 (19.9%) | 68 (28.5%) | 0.083 |
| Incident MACEs, n (%) | 57 (17.1%) | 38 (14.3%) | 46 (17.0%) | 43 (18.0%) | <0.001 |
| Follow-up time, months | 93.9 (66.4–117.1) | 100.4 (73.3–123.4) | 97.7 (69.3–118.0) | 94.0 (67.6–119.2) | 0.705 |
Data are given as mean (SD), median (IQR) or n (%).
Characteristics among clusters were compared by analysis of variance or Kruskal-Wallis test for continuous variables and χ2 test for categorical variables.
*Bonferroni corrected for multiple comparisons (p ≤ (0.05/12)=p ≤ 0.004).
AHI, apnoea–hypopnoea index; BMI, body mass index; CPAP, continuous positive airway pressure; CVDs, cardiovascular diseases; MACEs, major adverse cardiovascular events; OSA, obstructive sleep apnoea; TST90, sleep time with oxygen saturation below 90%.