Identifying Risk of Postoperative Cardiorespiratory Complications in OSA.

Background: Patients with OSA are at increased risk of postoperative cardiorespiratory complications and death. Attempts to stratify this risk have been inadequate, and predictors from large, well-characterized cohort studies are needed.

Research question: What is the relationship between OSA severity, defined by various polysomnography-derived metrics, and risk of postoperative cardiorespiratory complications or death, and which metrics best identify such risk?

Study design and methods: In this cohort study, 6,770 consecutive patients who underwent diagnostic polysomnography for possible OSA and a procedure involving general anesthesia within a period of 2 years before and at least 5 years after polysomnography. Participants were identified by linking polysomnography and health databases. Relationships between OSA severity measures and the composite primary outcome of cardiorespiratory complications or death within 30 days of hospital discharge were investigated using univariable and multivariable analyses.

Results: The primary outcome was observed in 5.3% (n = 361) of the cohort. Although univariable analysis showed strong dose-response relationships between this outcome and multiple OSA severity measures, multivariable analysis showed its independent predictors were: age older than 65 years (OR, 2.67 [95% CI, 2.03-3.52]; P < .0001), age 55.1 to 65 years (OR, 1.47 [95% CI, 1.09-1.98]; P = .0111), time between polysomnography and procedure of ≥ 5 years (OR, 1.32 [95% CI, 1.02-1.70]; P = .0331), BMI of ≥ 35 kg/m² (OR, 1.43 [95% CI, 1.13-1.82]; P = .0032), presence of known cardiorespiratory risk factor (OR, 1.63 [95% CI, 1.29-2.06]; P < .0001), > 4.7% of sleep time at an oxygen saturation measured by pulse oximetry of < 90% (T90; OR, 1.91 [95% CI, 1.51-2.42]; P < .0001), and cardiothoracic procedures (OR, 7.95 [95% CI, 5.71-11.08]; P < .0001). For noncardiothoracic procedures, age, BMI, presence of known cardiorespiratory risk factor, and percentage of sleep time at an oxygen saturation of < 90% remained the significant predictors, and a risk score based on their ORs was predictive of outcome (area under receiver operating characteristic curve, 0.7 [95% CI, 0.64-0.75]).

Interpretation: These findings provide a basis for better identifying high-risk patients with OSA and determining appropriate postoperative care.