GSTM1 and diabetes mellitus: The combined OR value and 95% confidence interval (CI) of all factors were: Combined with Diabetes (1.94, 1.51 ~ 2.50), Hb (1.82, 1.35 ~ 2.44), age (2.38, 1.06 ~ 5.34), catheter indwelling time (1.79, 1.21 ~ 2.66), serum albumin (2.26, 1.25 ~ 4.08), catheter indwelling site (3.29, 1.74 ~ 6.23) and the number of tube placement (5.40, 2.65 ~ 11.02).