Table 4.

Disease-free survival assessed by the Cox regression model. Significant values are in bold.

Variables	Disease-free survival
	HR	95% CI	p-value	aHRa	95% CI	p-value
Age at surgery, years	1.05	1.02–1.07	0.001	1.03	1.00–1.07	0.04
Female sex	0.87	0.54–1.38	0.55	0.48	0.23–0.98	0.04
BMI, kg/m2	0.96	0.91–1.00	0.06
Tumor site
Colon (reference)
Rectum	0.61	0.36–1.04	0.07
CRC stage
In situ, I, II (reference)
III, IV	3.23	2.08–5.01	< 0.001	3.15	1.85–5.36	< 0.001
Charlson comorbidity index	1.21	1.08–1.36	0.001
Complications of diabetes	2.31	1.39–3.84	0.001
Metformin use	0.36	0.23–0.56	< 0.001	0.31	0.18–0.54	< 0.001

HR, hazard ratio; CI, confidence interval.

^aAdjusted for age at surgery, sex, BMI, tumor site, CRC stage, Charlson comorbidity index, diabetes complications.