Predictive value of renal resistive index for the onset of acute kidney injury and its non-recovery: A systematic review and meta-analysis

The predictive value of Doppler-based renal resistive index (RRI) for acute kidney injury (AKI) has not been fully elucidated. The present meta-analysis was carried out to disclose the correlation between AKI and RRI, and to investigate the predictive value of RRI for the onset of AKI and its recovery.We searched PubMed, Embase, and Cochrane Library databases from inception to March 2019. The weighted mean difference (WMD) with a 95% confidence interval (CI) was used to assess the difference in RRIs between AKI and non-AKI patients. Moreover, the sensitivity and specificity were calculated, and summary receiver operating characteristic (SROC) curves were constructed. Meta-Disc and STATA were used for all statistical analyses.A total of 20 studies (14 for prediction of the onset of AKI and 6 for prediction of AKI short-term non-recovery) were included in our meta-analysis. The values of RRI (WMD = 0.07; 95% CI: 0.05 - 0.09; p < 0.0001) were significantly higher in AKI patients compared with non-AKI patients. The overall sensitivity and specificity of RRI for prediction of the onset of AKI were 72% (95% CI, 64 - 80%) and 79% (95% CI, 71 - 85%), respectively. As for prediction of AKI short-term non-recovery, the pooled sensitivity was 81% (95% CI: 64 - 91), and the pooled specificity was 80% (95% CI: 72 - 85). For the onset of AKI, the best predictive performance was observed for the RRI measured immediately after major surgery, and a cut-off value ≥ 0.715 also achieved superior predictive value.This study showed that the elevation of RRI may be related to the progression of AKI, and RRI could have good overall predictive value for the onset of AKI and its short-term non-recovery. Further studies in different clinical settings and patient groups are warranted before it could be widely used in clinical practice.