Table 3. Multivariable Risk-Adjusted Analysis of the Association Between Perioperative RBC Transfusion and the Development of Postoperative VTE, DVT, and PE^a.

Perioperative RBC Transfusion	Adjusted OR (95% CI)b
	VTE	DVT	PE
Perioperative RBC transfusion
No	1 [Reference]	1 [Reference]	1 [Reference]
Yes	2.1 (2.0-2.3)	2.2 (2.1-2.4)	1.9 (1.7-2.1)
Time of perioperative transfusion
None	1 [Reference]	1 [Reference]	1 [Reference]
Preoperative only	1.9 (1.5-2.3)	2.1 (1.6-2.6)	1.7 (1.2-2.5)
Intraoperative or postoperative only	2.1 (1.9-2.2)	2.2 (2.0-2.3)	1.9 (1.7-2.1)
Preoperative and intraoperative or postoperative	3.0 (2.5-3.5)	3.3 (2.7-3.9)	1.8 (1.3-2.6)

Abbreviations: DVT, deep venous thrombosis; OR, odds ratio; PE, pulmonary embolism; RBC, red blood cell; VTE, venous thromboembolism.

^aIncludes events within 30 d of a surgical procedure. Data were derived from the American College of Surgeons’ National Surgical Quality Improvement Program database for 2014.

^bThis was a complete-case analysis of 642 946 patients. Separate multivariable models were used for each exposure-outcome association shown. Each multivariable model was adjusted for age, sex, race, body mass index, functional health status before surgery, the American Society of Anesthesiology severity class, hospital length of stay, occurrence of sepsis, mechanical ventilation dependence, disseminated cancer, and work-related relative value units (as a surrogate for complexity of surgery).