Table 3.

Selected important variables for all complications and their descriptions

Category	Name	Description
	In/Out patient	Inpatient or outpatient surgery
Diagnosis code	ICD_9 code: 998.59 and 997.32	Diagnosis code of postoperative SSI and pneumonia
Microbiology test order	Abscess culture Blood culture Gram stain culture Sputum culture Urine culture	These are binary features to indicate if such microbiology test ordered or not during day 3 to day 30 after operation.
Microbiology test result	Escherichia. Coli Staphylococcus	These are binary features to indicate if the type of bacteria is positive or not no matter in which kind of microbiology test during day 3 to day 30 after operation.
Antibiotic use	Antibiotic_Superficial_SSI Antibiotic_Pneumonia Antibiotic_UTI	They are binary features to indicate if antibiotics is placed to patients during day 3 to day 30 after operation.
Laboratory results	Measurement_CR Measurement PLT Measurement_PREALAB Measurement WBCU	The number of measurements for creatinine, platelet count test, prealbumin, and urine white blood cells (WBCU).