ABSTRACT: Study Objective:To validate that the symptomless Multi-Variable Apnea Prediction index (sMVAP) is associated with Obstructive Sleep Apnea (OSA) diagnosis and assess the relationship between sMVAP and adverse outcomes in patients having elective surgery. We also compare associations between Bariatric surgery, where preoperative screening for OSA risk is mandatory, and non-Bariatric surgery groups who are not screened routinely for OSA. Methods:Using data from 40 432 elective inpatient surgeries, we used logistic regression to determine the relationship between sMVAP and previous OSA, current hypertension, and postoperative complications: extended length of stay (ELOS), intensive-care-unit-stay (ICU-stay), and respiratory complications (pulmonary embolism, acute respiratory distress syndrome, and/or aspiration pneumonia). Results:Higher sMVAP was associated with increased likelihood of previous OSA, hypertension and all postoperative complications (p < .0001). The top sMVAP quintile had increased odds of postoperative complications compared to the bottom quintile. For ELOS, ICU-stay, and respiratory complications, respective odds ratios (95% CI) were: 1.83 (1.62, 2.07), 1.44 (1.32, 1.58), and 1.85 (1.37, 2.49). Compared against age-, gender- and BMI-matched patients having Bariatric surgery, sMVAP was more strongly associated with postoperative complications in non-Bariatric surgical groups, including: (1) ELOS (Orthopedics [p < .0001], Gastrointestinal [p = .024], Neurosurgery [p = .016], Spine [p = .016]); (2) ICU-stay (Orthopedics [p = .0004], Gastrointestinal [p < .0001], and Otorhinolaryngology [p = .0102]); and (3) respiratory complications (Orthopedics [p =.037] and Otorhinolaryngology [p =.011]). Conclusions:OSA risk measured by sMVAP correlates with higher risk for select postoperative complications. Associations are stronger for non-Bariatric surgeries, where preoperative screening for OSA is not routinely performed. Thus, preoperative screening may reduce OSA-related risk for adverse postoperative outcomes.