Myllymaa Katja, Myllymaa Sami, Leppänen Timo, Kulkas Antti, Kupari Salla, Tiihonen Pekka, Mervaala Esa, Seppä Juha, Tuomilehto Henri, Töyräs Juha
Department of Clinical Neurophysiology, Kuopio University Hospital, PO Box 100, 70029, Kuopio, Finland.
Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
Sleep Breath. 2016 Mar;20(1):33-42. doi: 10.1007/s11325-015-1180-4. Epub 2015 Apr 21.
Weight loss leads to improvement of obstructive sleep apnea (OSA), based on frequency of respiratory events (apnea-hypopnea index, AHI). However, AHI does not incorporate the severity of individual obstruction events. The American Academy of Sleep Medicine suggests two alternative oxygen desaturation thresholds (ODT) for scoring of hypopneas. We hypothesize that lowering the ODT level increases the determined impact of weight loss on OSA severity. We investigate this during weight change with AHI and adjusted AHI. Adjusted AHI is a novel parameter incorporating both severity and number of the events.
Ambulatory polygraphic data of 54 OSA patients (F 15/M 39, 51.7 ± 8.4 years), divided into weight loss (>5 %, n = 20), control (weight change 0-5 %, n = 26), and weight gain (>5 %, n = 8) groups, were evaluated at baseline and after 5-year follow-up. Effect of ODT (ODT2%-ODT6%) on AHI and adjusted AHI was investigated.
The greatest changes in AHI (decrease in weight loss group and increase in weight gain group) were observed with ODT2%. Changes in AHI diminished with increasing ODT. In weight loss group, adjusted AHI showed a similar but non-significant trend. In contrast, the higher ODT was used in weight gain group, the greater increase in adjusted AHI resulted. Using adjusted AHI instead of AHI, led to a smaller number of patients (20 vs. 55 %, ODT3%) whose OSA severity category improved along weight loss.
Weight loss significantly reduced AHI. This reduction was highly dependent on selected ODT. The change in adjusted AHI did not occur in the same extent. This was expected as the more severe events which tend to remain during the weight loss have greater importance in adjusted AHI, while the event severity is neglected in AHI.
基于呼吸事件频率（呼吸暂停低通气指数，AHI），体重减轻可改善阻塞性睡眠呼吸暂停（OSA）。然而，AHI并未纳入个体阻塞事件的严重程度。美国睡眠医学会提出了两种用于低通气评分的替代氧饱和度下降阈值（ODT）。我们假设降低ODT水平会增加体重减轻对OSA严重程度的确定影响。我们在体重变化期间使用AHI和调整后的AHI对此进行研究。调整后的AHI是一个结合了事件严重程度和数量的新参数。
对54例OSA患者（女性15例/男性39例，年龄51.7±8.4岁）的动态多导睡眠图数据进行评估，这些患者分为体重减轻组（>5%，n = 20）、对照组（体重变化0 - 5%，n = 26）和体重增加组（>5%，n = 8），在基线时和5年随访后进行评估。研究ODT（ODT2% - ODT6%）对AHI和调整后AHI的影响。
使用ODT2%时观察到AHI的最大变化（体重减轻组下降，体重增加组增加）。随着ODT增加，AHI的变化减小。在体重减轻组中，调整后的AHI显示出类似但不显著的趋势。相反，在体重增加组中使用的ODT越高，调整后AHI的增加就越大。使用调整后的AHI而非AHI，导致随着体重减轻OSA严重程度类别改善的患者数量减少（20%对55%，ODT3%）。
体重减轻显著降低了AHI。这种降低高度依赖于所选的ODT。调整后AHI的变化程度不同。这是预期的，因为在体重减轻期间往往持续存在的更严重事件在调整后AHI中具有更大的重要性，而在AHI中忽略了事件严重程度。
