Six RCTs (n=624) were included in the main analysis. Twelve non-randomised studies (n=1,252) were included in additional sensitivity analyses.
Mortality.
There was no significant difference in survival between IHD and CRRT (RR 0.96, 95% CI: 0.85, 1.08, P=0.50) based on the 6 RCTS (fixed-effect). There was no evidence of statistically-significant heterogeneity across the studies (P=0.09). Similar results were obtained regardless of the inclusion of non-randomised studies, the CRRT technique used, the year of publication, or by controlling for baseline severity of illness. It was estimated that an additional trial with at least 1,250 patients would be required to detect a significant improvement (RR 1.2) in mortality with CRRT in comparison with IHD.
Renal recovery.
There was no statistically-significant difference in renal death between IHD and CRRT (RR 1.02, 95% CI: 0.89, 1.17, P=0.78) based on 371 patients in 4 RCTs (fixed-effect). There was no evidence of statistically-significant heterogeneity (Q=0.79, d.f.=3, P=0.85). Similarly, no statistically-significant difference in dialysis dependence was found (RR 1.19, 95% CI: 0.62, 2.27, P=0.60) and there was no evidence of statistical heterogeneity (Q=2.6, d.f.=3, P=0.78). It was estimated that, for renal death, the addition of a very large trial would be required to detect a significant difference between the therapies (number of patients provided). In contrast, one additional trial with 190 patients would be needed to show a statistically-significant difference in dialysis dependence in favour of CRRT if that trial showed around 50% reduction in dialysis dependence with CRRT.