Stata 14.1 outputs exploring the effect of several explanatory variables on primary and secondary outcomes with six or more included studies: death at day 30, recovery of kidney function, length of hospital and ICU stay. The covariates included in the models were: type of participant (typepatient); Fluid overload after randomisation in three categories(catpat); difference in the fluid overload after randomisation in the early group minus the standard group (Dif). The explanatory variables were defined as follows:   type of participants: participant with AKI related to non‐surgical cause versus participant with AKI related to surgical causes catpat: categories considering the amount of fluid overload (FO) after randomisation between both groups, according to the following: mild: FO<3 Lts (icatpat0); moderate: fluid overload between 3Lts to < 6 Lts (icatpat1); severe: fluid overload ≥ 6 Lts (icatpat2) Dif: absolute difference in fluid overload after randomisation between the standard group minus fluid overload after randomisation in the intervention group Modal: participant who receive CRRT modality and participant who receive both modalities (continuous and Intermittent) Hypot: difference of percentage in number of patients with hypotension between early group minus standard group We analysed several models for each outcomes. We present the model with the three covariates of each outcomes, including the full output of the STATA 14.1 statistics. In each model the covariates were typed in bold (see definitions above). The other code in tables were: Logrr: Relative risk of dichotomy outcomes ES: mean difference of continuous outcomes Coef.: value of the relative risk or the mean difference in their units P>t: probability that the logrr difference adjusted by other covariates could be related to chance if P is higher than 0.05 Std. Err: standard error of the coefficient t: test P>t: probability that the logrr difference adjusted by other covariates could be related to chance if P is higher than 0.05(not significant) 95% Conf. Interval: 95% confidence interval of the logrr or ES values. It is important to state the limitations of this meta‐regression because of the limited studies (9) for the number of covariates in the model.   Death at day 30 . xi: metareg logrr i.catpat typepatient dif, wsse(selogrr) bsest(reml) i.catpat _Icatpat_1‐2 (naturally coded; _Icatpat_1 omitted) note: _Icatpat_2 dropped because of collinearity numerical derivatives are approximate nearby values are missing Meta‐regression Number of obs = 6 REML estimate of between‐study variance tau2 = 0 % residual variation due to heterogeneity I‐squared_res = 0.00% Proportion of between‐study variance explained Adj R‐squared = .% Joint test for all covariates Model F(2,3) = 1.47 With Knapp‐Hartung modification Prob > F = 0.3598 See. Appendix 4.1   Death at day 30 . xi: metareg logrr hipot typepatient dif, wsse(selogrr) bsest(reml) Meta‐regression Number of obs = 9 REML estimate of between‐study variance tau2 = 0 % residual variation due to heterogeneity I‐squared_res = 31.02% Proportion of between‐study variance explained Adj R‐squared = .% Joint test for all covariates Model F(3,5) = 0.93 With Knapp‐Hartung modification Prob > F = 0.4902 See. Appendix 4.2   Death at day 30 . metareg logrr hipot typepatient dif modal, wsse(selogrr) bsest(reml) Meta‐regression Number of obs = 9 REML estimate of between‐study variance tau2 = 0 % residual variation due to heterogeneity I‐squared_res = 44.13% Proportion of between‐study variance explained Adj R‐squared = .% Joint test for all covariates Model F(4,4) = 0.58 With Knapp‐Hartung modification Prob > F = 0.6954 See. Appendix 4.3   Recovery of Kidney function in all patients . xi: metareg logrri.catpat typepatient dif, wsse(selogrr) bsest(reml) i.catpat _Icatpat 1‐2 (naturally coded; _Icatpat_1 omitted) Meta‐regression Number of obs = 6 REML estimate of between‐study variance tau2 = .007724 % residual variation due to heterogeneity I‐squared_res = 11.26% Proportion of between‐study variance explained Adj R‐squared = 44.71% Joint test for all covariates Model F (3,2) = 1.42 With Knapp‐Hartung modification Prob > F = 0.4389 See. Appendix 5.1   Renal recovery function in all patients . metareg logrr hipot typepatient dif, wsse(selogrr) bsest(reml) Meta‐regression Number of obs = 9 REML estimate of between‐study variance tau2 = .01708 % residual variation due to heterogeneity I‐squared_res = 53.90% Proportion of between‐study variance explained Adj R‐squared = ‐214.78% Joint test for all covariates Model F(3,5) = 0.32 With Knapp‐Hartung modification Prob > F = 0.8136 See. Appendix 5.2   Renal recovery function in all patients metareg logrr hipot typepatient dif modal, wsse(selogrr) bsest(reml) Meta‐regression Number of obs = 9 REML estimate of between‐study variance tau2 = .02433 % residual variation due to heterogeneity I‐squared_res = 59.28% Proportion of between‐study variance explained Adj R‐squared = ‐348.52% Joint test for all covariates Model F(4,4) = 0.30 With Knapp‐Hartung modification Prob > F = 0.8624. See. Appendix 5.3   Length at hospital stay metareg typepatient modal, wsse(_seES) bsest(reml) Meta‐regression Number of obs = 7 REML estimate of between‐study variance tau2 = .1255 % residual variation due to heterogeneity I‐squared_res = 76.81% Proportion of between‐study variance explained Adj R‐squared = 47.28% With Knapp‐Hartung modification See Appendix 6