Table 6.

The final multivariable prediction model for predicting postoperative infections in patients undergoing surgery

Predictor	Coefficient	SE	Odds ratio
Chest tube tip culturea	0.661	0.414	1.94
Duration of postoperative drainage	0.098	0.043	1.10
Smoking status (former)	0.326	0.442	1.39
Smoking status (current)	− 1.363	0.765	0.26
Constant	− 2.140	0.498

^aVariables used in the full model included smoking status, chest tube tip culture, duration of postoperative drainage, diabetes, and type of surgery. The goal was to evaluate chest tube tip culture in combination with other variables, and as such it was kept in the reduced final model despite being non-significant