Table 1. Sample description including polysomnography and pulse wave analysis parameters.
| IS + SE≤80% | IS + SE>80% | Controls | p–valuec | |
|---|---|---|---|---|
| n = 14 | n = 12 | n = 26 | ||
| Anthropometric datab | ||||
| Men (n) | 8 (57%) | 4 (33%) | 14 (54%) | 0.41 |
| Cardiovascular disease (n) | 0 (0%) | 0 (0%) | 2 (8%) | 0.35 |
| Age (years) | 48.5 (38.0–53.8) | 29.5 (24.3–33.8) | 31.5 (28.0–47.3) | 0.02 |
| BMI (kg/m2) | 23.2 (20.1–27.1) | 23.9 (21.8–29.7) | 22.4 (20.8–25.2) | 0.59 |
| Alcohol (glasses/week) | 1.0 (0.8–1.0) | 1.0 (0.0–1.0) | 1.0 (0.8–2.0) | 0.30 |
| Smoking (cigarettes/day) | 0.0 (0.0–0.0) | 0.0 (0.0–0.0) | 0.0 (0.0–0.0) | 0.69 |
| Years since IS diagnosis | 5.5 (3.3–7.8) | 5.0 (3.0–10.0) | n/a | 0.81 |
| Persistent IS ≥ 6 years (n) | 5 (36%) | 3 (25%) | n/a | |
| Pulse rate (bpm)a | 70.0 (63.0–74.0) | 75.0 (64.0–80.8) | 64.0 (62.0–72.0) | 0.13 |
| Systolic BP (mmHg) a | 117.5 (100.0–130.0) | 115.0 (100.3–128.8) | 110.0 (105.0–126.3) | 0.99 |
| Diastolic BP (mmHg) a | 70.0 (60.0–80.5) | 80.0 (64.0–83.8) | 70.0 (70.0–80.0) | 0.23 |
| Subjective sleep quality (questionnaires)b | ||||
| ISI Score | 19.0 (17.8–22.3) | 18.0 (15.3–19.0) | 1.0 (0.0–3.3) | 0.00 |
| No IS, ISI 0–7 (n) | 0 (0%) | 0 (0%) | 26 (100%) | |
| Mild IS, ISI 8–14 (n) | 0 (0%) | 2 (17%) | 0 (0%) | |
| Moderate IS, ISI 15–21 (n) | 8 (57%) | 9 (75%) | 0 (0%) | |
| Severe IS, ISI 22–28 (n) | 6 (43%) | 1 (8%) | 0 (0%) | |
| ESS Score | 10.0 (4.5–14.0) | 13.0 (9.0–15.0) | 5.0 (3.0–8.0) | 0.00 |
| ESS > 10 (n) | 7 (50%) | 7 (58%) | 0 (0%) | |
| PSQI Score | 13.0 (9.5–15.0) | 12.0 (10.0–14.0) | 3.0 (2.0–5.0) | 0.00 |
| PSQI > 5 (n) | 13 (93%) | 12 (100%) | 3 (12%) | |
| RLS-DI Score | -14.0 (-16.0- -10.0) | -10.0 (-12.0- -1.5) | -19.0 (-19.0- -14.0) | 0.00 |
| Objective sleep quality (polysomnography) b | ||||
| SE (%) | 67.1 (37.3–74.7) | 88.1 (85.7–89.9) | 88.0 (83.0–93.1) | 0.00 |
| SOL (minutes) | 35.5 (11.7–55.0) | 15.7 (5.9–19.7) | 19.0 (9.9–28.9) | 0.02 |
| TST (minutes) | 310.5 (180.3–361.1) | 414.7 (409.6–424.1) | 416.8 (397.5–440.9) | 0.00 |
| TST ≥ 6 hours (n) | 4 (29%) | 12 (100%) | 23 (89%) | |
| WASO (% of TST) | 16.1 (10.4–29.4) | 14.4 (7.2–21.2) | 16.5 (8.4–21.5) | 0.38 |
| S1 (% of TST) | 18.8 (15.1–25.0) | 15.3 (13.1–35.2) | 19.0 (10.2–28.0) | 0.80 |
| S2 (% of TST) | 44.6 (40.7–54.1) | 48.5 (41.6–53.1) | 45.1 (35.4–53.4) | 0.67 |
| SWS (% of TST) | 20.3 (16.8–27.7) | 23.0 (19.6–28.5) | 22.4 (19.9–27.8) | 0.47 |
| REM (% of TST) | 12.6 (8.6–16.2) | 15.6 (13.1–35.2) | 13.4 (8.9–14.9) | 0.20 |
| Snoring (% of TST) | 18.0 (1.6–46.0) | 13.9 (2.7–27.9) | 15.6 (4.3–31.4) | 0.92 |
| AHI (events/hour) | 1.5 (0.3–16.0) | 1.3 (0.7–3.0) | 1.3 (0.4–3.8) | 0.84 |
| AHI 5–14 (n) | 1 (7%) | 1 (8%) | 3 (12%) | |
| AHI ≥ 15 (n) | 3 (21%) | 0 (0%) | 2 (8%) | |
| Oxygen desaturation index | 1.7 (0.5–22.7) | 1.1 (0.4–2.5) | 1.1 (0.3–2.6) | 0.54 |
| Arousal index | 10.8 (6.7–15.6) | 5.6 (5.1–10.7) | 6.5 (4.7–8.4) | 0.04 |
| PLMI (events/hour) | 11.9 (8.4–25.6) | 2.1 (0.9–4.0) | 2.1 (0.8–7.4) | |
| PLMI > 15 | 2 (14%) | 0 (0%) | 1 (4%) | |
| Cardiovascular parameters (pulse wave analysis) b | ||||
| Pulse rate (average bpm) | 66.5 (57.5–70.0) | 66.0 (63.0–68.5) | 58.0 (51.8–63.3) | 0.01 |
| PPT (ms) | 168.9 (147.4–232.0) | 236.9 (214.5–254.0) | 243.5 (179.6–284.2) | 0.01 |
| Pulse RSA | 36.9 (30.6–44.9) | 38.3 (34.1–49.3) | 47.2 (33.6–60.6) | 0.24 |
| PWA-I | 9.0 (6.8–10.5) | 9.2 (8.5–10.8) | 9.8 (7.5–11.1) | 0.64 |
| CRI | 0.2 (0.0–0.7) | 0.0 (0.0–0.4) | 0.0 (0.0–0.3) | 0.05 |
IS, insomnia; SE, sleep efficiency; BMI, body mass index; bpm, beats per minute; BP, blood pressure; mmHg, millimeters of mercury, unit for blood pressure; ISI, Insomnia Severity Index; ESS, Epworth Sleepiness Scale, scores above 10 indicate excessive daytime sleepiness and it is recommended to seek medical advice; PSQI, Pittsburgh Sleep Quality Index, scores above 5 indicate bad sleep quality; RLS-DI, Restless Leg Syndrome Diagnostic Index; SOL, sleep onset latency, stage 2; TST, total sleep time; WASO, wake time after sleep onset; S1, sleep stage 1; S2, sleep stage 2; SWS, slow-wave-sleep stage; REM, rapid-eye-movement sleep stage; AHI, apnea-hypopnea-index; PLMI, periodic leg movement index; PPT, pulse propagation time; ms, milliseconds; pulse RSA, pulse respiratory sinus arrhythmia; PWA-I, pulse wave amplitude index; CRI, cardiac risk index; n/a, not applicable.
ameasured before polysomnography.
bDisplayed are median (interquartile range) or number (proportion).
cKruskal-Wallis test was used for continuous variables, Chi-square test for dichotomous variables. Significant values on 0.05 level are highlighted.