The Role of Lung Function in Adverse Health Outcomes Related to Sleep-disordered Breathing. New Insights into the Overlap Syndrome.
The Role of Lung Function in Adverse Health Outcomes Related to Sleep-disordered Breathing. New Insights into the Overlap Syndrome.
复制标题
肺功能在与睡眠呼吸障碍相关的不良健康结果中的作用。
DOI：
10.1164/rccm.201604-0682ed
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发表时间：
2016
影响因子：
24.7
通讯作者：
Rowley,JamesA
中科院分区：
文献类型：
--
作者：
Sankari,Abdulghani;Rowley,JamesA
一些研究已经评估了慢性肺部疾病如慢性阻塞性肺疾病（COPD）和睡眠呼吸障碍（SDB）或所谓的“重叠综合征”之间的关系。这些研究已经证实，与没有SDB或接受适当OSA治疗的患者相比，患有COPD且未接受治疗的中度至重度阻塞性睡眠呼吸暂停（OSA）患者的长期生存率更差（1，2）。重叠综合征患者不良临床结局的机制尚不清楚。推定的解释分为缺氧相关原因和非缺氧相关原因。众所周知，COPD和SDB患者在睡眠期间缺氧会恶化（3）。缺氧诱导的氧化应激和炎症可能导致死亡率增加。还报告了肺功能降低对无已知肺部病理学的队列死亡率的影响。在布法罗健康研究中，基线时FEV 1较低与29岁时全因和缺血性心脏病死亡率增加相关（4）。来自国家健康和营养调查数据集的数据也显示，基线时较低的FEV 1与心血管死亡率增加相关（5）。这些发现的可能原因包括：（1）FEV 1是一种由影响肺和心血管系统的常见假定因素引起的附带现象，（2）受到其他未测量变量的混淆，以及（3）低FEV 1受试者的肺部炎症增加，导致全身炎症增加。因此，考虑到较低的FEV 1和较高的呼吸暂停低通气指数（AHI）均与死亡率增加相关，并且已知COPD和OSA之间存在增加死亡率的相互作用，因此可以合理地假设FEV 1和AHI之间存在导致死亡率增加的相互作用。在本期杂志中，Putcha及其同事（pp. 1007-1014）通过分析来自睡眠心脏健康研究（6）的6,173名参与者的数据，评估肺功能与全因死亡率之间的关系。使用肺量测定法测量肺功能，以估计FEV 1和FVC（7）。该研究的主要终点是中位随访期超过10年的全因死亡率。根据2011年底进行的普查，死亡病例总数为1 457例。SDB的存在和严重程度进行了分类，根据AHI从一个无人值守的全家庭睡眠研究。使用与4%或更多的去饱和度相关的30%的流量下降来对呼吸不足进行评分。比例回归模型用于计算校正几种合并症和混杂因素（如年龄、性别、种族、体重指数、吸烟和心血管疾病）后的死亡率风险比。与其他队列的研究结果相似，该小组发现肺功能降低和SDB严重程度增加均与全因死亡率增加相关。然而，肺功能对死亡率的影响取决于SDB的严重程度。FEV 1每减少200 ml，无SDB受试者的死亡率增加11%，SDB受试者仅增加6%。此外，当评估中重度SDB患者的FEV 1值时，肺功能降低与全因死亡风险增加无关。夜间缺氧指数和SDB的严重程度之间也有很强的负相关性。然而，在FEV 1较低的受试者中，这种负相关性并不明显。这些结果表明，SDB的死亡率...
Several studies have assessed the relationship between chronic pulmonary disorders such as chronic obstructive pulmonary disease (COPD) and sleep-disordered breathing (SDB) or what is called “overlap syndrome.” These studies have established that patients with COPD with untreated moderate to severe obstructive sleep apnea (OSA) have worse long-term survival compared with those who have no SDB or received appropriate treatment of OSA (1, 2). The mechanism of adverse clinical outcome in patients with overlap syndrome is not clear. Putative explanations are divided into hypoxia-related and non-hypoxia-related causes. Hypoxia is known to worsen during sleep in patients with both COPD and SDB (3). Hypoxia-induced oxidative stress and inflammation could then contribute to increased mortality. The effect of lower lung function on mortality in cohorts without known lung pathology has also been reported. In the Buffalo Health Study, a lower FEV1 at baseline was associated with both increased all-cause and ischemic heart disease mortality at 29 years (4). Data from the National Health and Nutrition Examination Survey dataset also showed that a lower FEV1 at baseline is associated with increased cardiovascular mortality (5). Possible reasons for these findings include the following:(1) FEV1 is an epiphenomenon resulting from a common putative factor affecting both pulmonary and cardiovascular systems,(2) confounding by other unmeasured variables, and (3) increased pulmonary inflammation in subjects with low FEV1, resulting in increases in systemic inflammation. Therefore, given that both lower FEV1 and higher apnea hypopnea index (AHI) are associated with increased mortality, and that there is a known interaction between COPD and OSA in increasing mortality, it would be reasonable to hypothesize that there would be an interaction between FEV1 and AHI resulting in increased mortality. In this issue of the Journal, Putcha and colleagues (pp. 1007–1014) assess the relationship between lung function and all-cause mortality by analyzing data obtained from 6,173 participants from the Sleep Heart Health Study (6). Lung function was measured using spirometry to estimate FEV1 and FVC (7). The primary end point of the study was all-cause mortality over a median follow-up period of more than 10 years. The overall mortality cases were 1,457 deaths, based on censoring conducted by the end of 2011. The presence and severity of SDB were categorized according to AHI obtained from an unattended full-home sleep study. Hypopneas were scored using a 30% drop in flow that is associated with desaturations of 4% or more. Proportional regression models were used to calculate the hazard ratios for mortality after adjusting for several comorbidities and confounding factors (such as age, sex, race, body mass index, tobacco smoking, and cardiovascular disease). Similar to findings in other cohorts, the group found that both reduced lung function and increased SDB severity were associated with increased all-cause mortality. However, the influence of lung function on mortality was dependent on the severity of SDB. For every 200-ml decrease in FEV1, mortality increased by 11% in subjects without SDB, and only 6% in subjects with SDB. Furthermore, when assessing FEV1 values in moderate to severe SDB, reduced lung function was not associated with an increased risk for all-cause mortality. There were also strong inverse associations between nocturnal hypoxia indices and severity of SDB. However, the inverse associations were not as pronounced in subjects with lower FEV1. These results would indicate that mortality in SDB …