3.4.1 Mortality rate
Nineteen studies were included, which including 1070 patients, with 542 in the CRRT group and 528 in the control group. There was no statistical heterogeneity among the studies. The fixed effect model was used to combine the effect sizes. The results showed that the mortality rate of the CRRT group was significantly lower than that of the control group, and the difference was statistically significant(RR=0.44,95%CI0.34 to 0.57,P< 0.000001)(Fig.3).