Obstructive sleep apnea (OSA) is a chronic condition characterized by episodes of apnea and
hypoxemia caused by upper airway collapse. These episodes lead to symptoms such as daytime
fatigue and sleepiness in addition to multiple effects on health including hypertension,
stroke, cardiovascular disease and diabetes. Obesity, defined by the World Health
Organization and the United States National Institute of Health as a body mass index (BMI)
≥30 kg/m2 is a major risk factor for OSA and along with the obesity epidemic, the prevalence
of OSA has been increasing and is estimated to be around 3-7% in the United States. In 2017
The American Gastroenterological Association release the Practice guide on Obesity and Weight
management, Education and Resources (POWER) that provides guidance on obesity management.
This is in recognition that gastroenterologists are at the frontline of managing patients
with multiple obesity related conditions such as non-alcoholic fatty liver disease,
non-alcoholic steatohepatitis, gastroesophageal reflux, Barrett's esophagus, and colon
cancer. In the midst of these guidelines, recognition of extra gastrointestinal obesity
related conditions such as OSA remains an important task as this can have important long-term
health consequences.
There are different tools modalities to screen for OSA such as STOP-BANG questionnaire (SBQ)
and the Epworth Sleepiness scale (ESS). The SBQ was originally developed to screen patients
in the pre-operative setting as this population may be at higher risk for post-operative
complications, however this tool has been validated by multiple studies to identify patients
that may be at high risk for OSA. A systematic review and meta-analysis on the performance of
SBQ in different populations showed a sensitivity of 90%, 94% and 96% to detect any OSA
(Apnea-Hypopnea Index (AHI) ≥ 5), moderate-to-severe OSA (AHI ≥15), and severe OSA (AHI ≥30)
respectively. The ESS is a simple and validated questionnaire for assessing excessive daytime
sleepiness in the context of sleep disorders and has been suggested as a tool to identifying
patient with OSA. Studies comparing ESS with SBQ showed that although SBQ identify more
patient with OSA, the ESS has a higher specificity which is potentially of use in conjunction
with another higher sensitivity modality such as SBQ may improve the diagnostic accuracy
other screening modalities. Although the sensitivity of Berlin, STOP and STOP-Bang
questionnaires was generally high, the low specificity of these questionnaires results in
increased false positives and failure of exclusion of individuals at low risk.
The high sensitivity of SBQ, high specifity of ESS and ease in performing these questionnaire
makes it an ideal tool to screen patients for OSA in the endoscopy unit. Given the potential
cardiorespiratory decompensations in patients with OSA, multiple studies have used this
questionnaire to determine factors associated with airway maneuvers (AM) and sedation related
complications (SRC). In one study of patients undergoing advanced endoscopic procedures a SBQ
score ≥3 (SBQ+) was associated with increased risk of hypoxemia and the use of AM. These
patients also had a mean BMI of 31.4 kg/m2 which is defined as obesity class I. A similar
study on patients undergoing elective EGD and colonoscopy found no correlation between SBQ+
patients and SRC or AM, however it should be noted that the mean BMI in this SBQ+ population
was 28.3 kg/m2 which does not meet criteria for obesity. Although not statistically
significant there was a trend towards a higher use of AM in the higher BMI group (p=0.066).
In addition the combined analysis of adverse events for EGD and colonoscopies together can be
problematic since only about half of the patients on the study (n=120) underwent EGD which
has a higher risk of transient hypoxemia than colonoscopy, because of the potential of direct
impingement of the airway, laryngeal irritation or micro aspiration during esophageal
intubation17. Also the use of propofol was not standardized and other methods of sedation
were used such as benzodiazepine and opioids.