High Prevalence of Sleep Apnea in Bariatric Surgery Patients

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Most people with a body mass index (BMI) of 30 or higher who were undergoing bariatric surgery were found to have obstructive sleep apnea (OSA). These patients reported poor sleep quality, which was confirmed by objective sleep evaluations.

Obesity significantly increases the risk of developing OSA, a condition that causes breathing to temporarily stop or become shallow while a person is asleep. This can lead to reduced quality and quantity of sleep, as well as symptoms of drowsiness and fatigue during the day.

“Obesity causes changes in the structure and function of the respiratory system, particularly by increasing fat in the upper airway, leading to narrowing problems in the upper airway,” wrote a group of investigators from Kosin University in Korea. “Furthermore, obesity induces abnormal constriction of upper airway muscles during sleep, further promoting breathing interruptions.”

Investigators conducted a retrospective analysis using sleep study questionnaires, polysomnography reports and other medical information from 137 patients with obesity who were undergoing surgery at Kosin University Gospel Hospital between January 2019 and September 2022.

The Korean version of the Pittsburgh Sleep Quality Index (K-PSQI) and the Korean version of the Insomnia Severity Index (ISI-K) were used to measure sleep quality, and the Stanford Sleepiness Scale (SSS) and the Korean version of the Epworth Sleepiness Scale (KESS) were used to determine daytime sleepiness. Other assessments included the Korean version of the Beck Depression Inventory (K-BDI-II) and the Korean version of the World Health Organization Quality of Life-BREF (WHOQOL-BREF). Patients also underwent polysomnography, a tool used to diagnosis and assess sleep disorders.

Among the cohort, most patients were female (63.5%) and the average age was 38.29 years. Most patients reported comorbidities, including hypertension (45.3%) and type 2 diabetes (40.1%).

The study found a significant link between objective sleep assessments — the apnea-hypopnea index (AHI) — and subjective assessments, such as the K-PSQI, ISI-K and KESS. This means that poorer objective sleep quality was associated with worse self-reported sleep experiences. However, the SSS did not show a meaningful connection with objective sleep measures.

Additionally, higher scores on the K-BDI-II, which measures anxiety, were linked to poorer sleep quality. Quality of life, measured by the WHOQOL-BREF test, showed a negative relationship with poor sleep — suggesting that worse sleep was linked to a lower quality of life.

Although there were no statistically significant differences regarding total sleep time, sleep efficiency, sleep onset latency, rapid eye movement (REM) sleep onset latency and wake after sleep onset among patients, those with higher BMI had corresponding AHI increases.

Factors such as being older, being male and having a higher BMI were identified as key risks for OSA. Regression analysis revealed the men in the group were 5.79 times more likely to be diagnosed with severe OSA than women, and for every 1-year increase in age, an OSA diagnosis increased by 1.04 times. Similarly, for every one-unit increase in BMI, the likelihood of diagnosis increased by 1.08 times.

Investigators noted the retrospective study design using patient information from a single institution hindered the study, as it may have introduced selection bias. However, the results offer a unique understanding of this specific patient population. They hypothesized that recruiting a larger sample or using prospective data collection could fix this limitation.

“We are preparing for additional cohort enrollment and analysis, intending to scrutinize observations both before and after surgery,” investigators concluded. “Through further analysis, we aim to review areas requiring effective intervention plans.”