Obstructive Sleep Apnea Screening and Postoperative Mortality in a Large Surgical Cohort

Study Questions:

Does a prior diagnosis of obstructive sleep apnea (OSA) or a positive screen for OSA increase the risk for 30-day or 1-year postoperative mortality?

Methods:

B-J APNEAS (Barnes-Jewish Apnea Prevalence in Every Admission Study) was a prospective cohort study. Unselected adult surgical patients were prospectively enrolled between February 2006 and April 2010. All patients completed preoperative OSA screening, and those who were at risk for OSA according to screening tools received targeted postoperative interventions. Screening scores obtained were: Berlin, Flemons, STOP (loud Snoring, daytime Tiredness, Observed apneas, and high blood Pressure), and STOP-BANG (STOP, plus body mass index [BMI], age, neck circumference, and gender).

Results:

A total of 14,962 patients were sampled, of whom 1,939 (12.9%) reported a history of OSA. All four screening tools identified a high prevalence of undiagnosed patients at risk for OSA (9.5%-41.6%), but agreement among screens was not strong, with ĸ statistic ranging from 0.225 to 0.611.There was no significant difference in 30-day postoperative mortality between patients with possible OSA (based on their history or on a positive OSA screen with any of the four instruments) and the rest of the surgical population. Significant differences in 1-year mortality were noted between the low-risk and high-risk groups as identified by the Flemons’ (4.96% vs. 6.91%; p < 0.0001), STOP (5.28% vs. 7.57%; p < 0.0001), and STOP-BANG (4.13% vs. 7.45%; p < 0.0001) screens. After adjusting for risk factors, none of the OSA screening tools independently predicted mortality rate up to 1 year postoperatively.

Conclusions:

The authors concluded that neither a prior diagnosis of OSA nor a positive screen for OSA risk was associated with increased 30-day or 1-year postoperative mortality. However, differences in 1-year postoperative mortality were noted with three of the screening tools.

Perspective:

This large prospective cohort study examined screening tools for OSA and postoperative morbidity and mortality. All four screening tools demonstrated a moderately high agreement, though they had higher concordance with each other identifying negative OSA cases than reporting positive ones. The four consistent characteristics common to patients that screened positive for OSA were male gender, weight, older age, and comorbid conditions such as hypertension. One important patient characteristic not mentioned, which could have been a confounder here, was cancer status. Future studies will need to examine if indeed OSA itself is independently associated with increased perioperative morbidity and mortality, and whether universal utilization of quality improvement initiatives should be implemented to reduce perioperative risks associated with OSA.

Clinical Topics: Heart Failure and Cardiomyopathies, Prevention, Hypertension, Sleep Apnea

Keywords: Snoring, Neoplasms, Berlin, Fatigue, Hypertension, Sleep Apnea, Obstructive, Sleep Apnea Syndromes


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