Sleep Apnea-Specific Hypoxic Burden and Postoperative Outcomes of Major Noncardiothoracic Surgery.

Importance: Obstructive sleep apnea (OSA) is a highly prevalent and heterogeneous condition that predisposes to postoperative complications. Adequate metrics of OSA severity to stratify postoperative risk in a clinical setting are needed. Objective: To evaluate whether the sleep apnea-specific hypoxic burden (SASHB) is associated with postoperative cardiovascular (CV) complications and mortality among patients with OSA undergoing major noncardiothoracic surgery. Design, Setting, and Participants: Multicenter clinic-based cohort linked with a health administrative database involving adult patients diagnosed with OSA between May 2007 and December 2018 who underwent major noncardiothoracic surgery between OSA diagnosis and December 2024. Data were analyzed from January to December 2025. Exposure: SASHB defined as the area under the desaturation curve associated with sleep-related obstructive respiratory events. Main Outcomes and Measures: The primary outcome was a composite of stroke, atrial fibrillation, heart failure, myocardial infarction, venous thromboembolism, and all-cause mortality within 30 days of surgery. The association of SASHB and other OSA severity metrics with the primary outcome was investigated using univariable and multivariable analyses. Results: Among 2286 patients with OSA (median [IQR] age, 58 [49-66] years; 1472 [64.4%] men) who underwent major noncardiothoracic surgery a median (IQR) of 4.5 (1.9-7.5) years after OSA diagnosis, the primary outcome occurred in 80 patients (3.5%) within 30 days of surgery. The rate of events increased significantly from 1.6% (12 events) in patients with low SASHB (<32% min/h) to 5.8% (44 events) in those with high SASHB (≥80% min/h) at diagnosis. Compared with patients with low SASHB, patients with higher SASHB at diagnosis exhibited increased odds for the primary outcome (adjusted odds ratios, 1.76; 95% CI, 0.86-3.59 and 2.79; 95% CI, 1.42-5.49 for SASHB 32 to <80% and ≥80% min/h, respectively). A risk score based on age, emergency admission before surgery, and SASHB was associated with the primary outcome (area under receiver operating characteristic curve, 0.73; 95% CI, 0.68-0.77). Similar findings were obtained using a simplified version of SASHB automatically derived from the single oximetry signal extracted from diagnostic sleep studies. Conclusions and Relevance: Among OSA patients undergoing major noncardiothoracic surgery, SASHB was significantly associated with the risk of 30-day postoperative mortality and CV complications. Further research is needed to determine whether interventions guided by SASHB scores can modify postoperative risk in patients with OSA.