Respiratory Department, Tianjin Medical University General Hospital, Tianjin, China.
Sleep Breath. 2012 Mar;16(1):31-40. doi: 10.1007/s11325-011-0481-5. Epub 2011 Jan 19.
This study seeks to determine whether scores of a short questionnaire assessing subjective daytime sleepiness (Epworth Sleepiness Scale [ESS]) are associated with blood pressure (BP) level, BP profile, and prevalence of related coronary artery disease (CAD) and cerebrovascular disease (CVD) in obstructive sleep apnea (OSA) patients diagnosed by polysomnography (PSG).
Twenty university hospital sleep centers in China mainland were organized by the Chinese Medical Association to participate in this study. Between January 2004 and April 2006, 2,297 consecutive patients (aged 18-85 years; 1,981 males and 316 females) referred to these centers were recruited. BP assessments were evaluated at four time points (daytime, evening, nighttime, and morning) under standardized conditions. Anthropometric measurements, medical history of hypertension, CAD, and CVD were collected. ESS score was calculated for each participant and at the night of BP assessment, nocturnal PSG was performed and subjects were classified into four groups based on the apnea-hypopnea index (AHI) from PSG as follows: control group (control, n = 213) with AHI < 5; mild sleep apnea (mild, n = 420) with AHI ≥ 5 and <15; moderate sleep apnea (moderate, n = 460) with AHI ≥ 15 and <30; and severe sleep apnea (severe, n = 1,204) with AHI ≥ 30. SPSS 11.5 software package was used for the relationships between ESS and BP profile and prevalence of CAD and CVD.
ESS is correlated positively with average daytime, nighttime, evening, and morning BP before and even after controlling for confounding effects of age, sex, BMI, AHI, and nadir nocturnal oxygen saturation (before--r = 0.182, 0.326, 0.245, and 0.329, respectively, all P values < 0.001; after--r = 0.069, 0.212, 0.137, and 0.208, respectively, all P values < 0.001). In the severe group, nighttime, evening, morning average BPs (ABPs), the ratio of nighttime/daytime average BP (ratio of nighttime average BP to daytime average BP), and prevalence of hypertension, drug-resistant hypertension (R-HTN), isolated nighttime hypertension (IN-HTN), CAD, and CVD in excessive daytime sleepiness (EDS, ESS ≥ 11) subjects are higher than those in non-EDS (ESS 0-10; t/χ(2) = -8.388, -6.207, -8.607, -5.901, 12.742, 38.980, 16.343, 59.113, and 67.113, respectively; all P values < 0.05). For EDS subjects in the moderate group but not in the control and mild group, nighttime ABP and the ratio of nighttime/daytime average BP are higher (t = -2.086 and -3.815, respectively, all P values < 0.05). Linear fitting with ESS and the ratio of nighttime/daytime average BP shows a positive correlation (r(2) = 0.049, P < 0.001).
In severe OSA patients with comparable AHI, EDS may identify a subset of individuals with OSA at higher risk of hypertension, R-HTN, IN-HTN, CAD, and CVD. Overall, nighttime ABP seems to be more sensitive to be influenced by EDS than other ABP parameters. Future studies should investigate the potential dose-effect relationship between EDS and hypertension and the possibility that diagnosis and treatment of EDS could aid in BP reduction and ultimately in decreased morbidity and mortality from cardiovascular and cerebrovascular complications (TMUIRB20010002 at www.clinicaltrials.gov ).
本研究旨在探讨主观日间嗜睡（Epworth 嗜睡量表 [ESS]）评分与阻塞性睡眠呼吸暂停（OSA）患者的血压（BP）水平、BP 谱和相关冠状动脉疾病（CAD）和脑血管疾病（CVD）患病率之间的关系，这些患者是通过多导睡眠图（PSG）诊断的。
中国医学协会组织了中国内地 20 家大学医院睡眠中心参与本研究。2004 年 1 月至 2006 年 4 月，共招募了 2297 名连续就诊的患者（年龄 18-85 岁；1981 名男性，316 名女性）。在标准化条件下，在四个时间点（白天、傍晚、夜间和清晨）评估 BP 评估。收集了人体测量学测量值、高血压、CAD 和 CVD 的病史。为每位参与者计算 ESS 评分，并在 BP 评估的夜间进行了夜间 PSG，根据 PSG 的呼吸暂停-低通气指数（AHI）将受试者分为以下四个组：对照组（control，n = 213），AHI < 5；轻度睡眠呼吸暂停（mild，n = 420），AHI ≥ 5 且 <15；中度睡眠呼吸暂停（moderate，n = 460），AHI ≥ 15 且 <30；重度睡眠呼吸暂停（severe，n = 1204），AHI ≥ 30。使用 SPSS 11.5 软件包分析 ESS 与 BP 谱和 CAD 和 CVD 患病率之间的关系。
ESS 与平均白天、夜间、傍晚和清晨 BP 呈正相关，甚至在控制年龄、性别、BMI、AHI 和最低夜间血氧饱和度等混杂因素后仍然如此（之前--r = 0.182、0.326、0.245 和 0.329，所有 P 值均<0.001；之后--r = 0.069、0.212、0.137 和 0.208，所有 P 值均<0.001）。在严重组中，夜间、傍晚、清晨平均 ABPs（ABPs）、夜间/白天平均 BP 比值（夜间平均 BP 与白天平均 BP 的比值）以及 EDS（ESS ≥ 11）受试者的高血压、耐药性高血压（R-HTN）、孤立性夜间高血压（IN-HTN）、CAD 和 CVD 的患病率均高于非 EDS（ESS 0-10；t/χ²= -8.388、-6.207、-8.607、-5.901、12.742、38.980、16.343、59.113 和 67.113，所有 P 值均<0.05）。对于中度组中的 EDS 受试者，但不是对照组和轻度组中的 EDS 受试者，夜间 ABPs 和夜间/白天平均 BP 比值更高（t = -2.086 和 -3.815，所有 P 值均<0.05）。ESS 和夜间/白天平均 BP 比值的线性拟合呈正相关（r²= 0.049，P < 0.001）。
在具有可比 AHI 的严重 OSA 患者中，EDS 可能确定了一组 OSA 风险更高的个体，这些患者易患高血压、R-HTN、IN-HTN、CAD 和 CVD。总体而言，夜间 ABPs 似乎比其他 ABPs 参数更容易受到 EDS 的影响。未来的研究应该探讨 EDS 与高血压之间的潜在剂量-效应关系，以及诊断和治疗 EDS 是否有助于降低 BP，最终降低心血管和脑血管并发症的发病率和死亡率（TMUIRB20010002，在 www.clinicaltrials.gov 上）。
