Table 2.
The clinical characteristics in the patients stratified by flow-mediated vasodilation
| 1st quartile | 2nd quartile | 3rd quartile | 4th quartile | P value | |
|---|---|---|---|---|---|
| Number | 12 | 13 | 12 | 13 | — |
| %FMD (%) | 7.3±1.4 | 4.7±0.3** | 3.3±0.4**,† | 1.5±0.9**,‡,§ | <0.001 |
| Age (years) | 57±15 | 59±12 | 61±10 | 57±16 | 0.87 |
| BMI (kg/cm2) | 25.0±6.2 | 27.0±4.9 | 28.2±4.3 | 27.8±4.7 | 0.43 |
| Smoking (N [%]) | 3 [25] | 6 [46] | 3 [25] | 4 [31] | 0.63 |
| Hypertension (N [%]) | 6 [50] | 5 [39] | 9 [75] | 11 [85] | 0.06 |
| Diabetes mellitus (N [%]) | 3 [25] | 2 [15] | 4 [33] | 7 [54] | 0.19 |
| Dyslipidemia (N [%]) | 2 [17] | 5 [39] | 2 [17] | 6 [46] | 0.25 |
| ARB (N [%]) | 1 [8] | 1 [8] | 1 [8] | 5 [38] | 0.09 |
| ACE-I (N [%]) | 1 [8] | 0 [0] | 0 [0] | 1 [8] | 0.55 |
| Ca channel blocker (N [%]) | 1 [8] | 1 [8] | 0 [0] | 4 [31] | 0.10 |
| AHI (/hour) | 49.3±24.6 | 41.3±21.2 | 50.0±23.9 | 38.7±20.9 | 0.51 |
| OAI (/hour) | 24.6±26.1 | 13.4±10.6 | 18.3±25.2 | 8.4±8.8 | 0.19 |
| CAI (/hour) | 0.6±0.7 | 1.1±1.7 | 2.3±5.4 | 0.4±1.0 | 0.36 |
| HI (/hour) | 22.0±12.7 | 23.7±16.2 | 26.5±16.1 | 29.1±16.4 | 0.67 |
| TST (minute) | 347±80 | 425±103 | 373±55 | 418±60 | 0.04 |
| 3%ODI (/hour) | 33.3±21.0 | 27.2±13.4 | 43.7±21.9 | 30.5±20.9 | 0.19 |
| Averaged SpO2 (%) | 94.5±1.8 | 94.5±1.8 | 93.2±1.6 | 93.9±1.7 | 0.22 |
| Lowest SpO2 (%) | 73.7±11.5 | 77.4±7.7 | 75.5±8.1 | 73.0±11.0 | 0.66 |
| SpO2 < 90% (%) | 7.9±10.2 | 6.7±6.9 | 9.5±10.4 | 8.3±9.1 | 0.90 |
| TDS (% × hour) | 30.6±6.8 | 38.4±11.8 | 43.2±10.7* | 42.8±12.1* | 0.02 |
Abbreviations: FMD, flow-mediated vasodilation; BMI, body mass index; ARB, angiotensin receptor blocker; ACE-I, angiotensin-converting enzyme inhibitor; Ca, calcium; AHI, apnea-hypopnea index; OAI, obstructive apnea index; CAI, central apnea index; HI, hypopnea index; TST, total sleep time; ODI, oxygen desaturation index; SpO2, arterial oxygen saturation; TDS, time desaturation summation index.
*vs. 1st quartile group, P < 0.05. †vs. 2nd quartile group, P < 0.01. **vs. 1st quartile group, P < 0.001. ‡vs. 2nd quartile group, P < 0.001. §vs. 3rd quartile group, P < 0.001.