Risk factors and mortality of postoperative acute kidney injury (AKI) in newborns across geographical regions, surgical type, and national economic levels: a systematic review and meta-analysis.

BACKGROUND

It is noted that postoperative acute kidney injury (AKI) in neonates is known to be associated with adverse outcomes, yet its incidence and risk factors remain incompletely elucidated. The current study aims to improve the understanding of postoperative AKI in neonates by systematically evaluating its incidence, diagnostic criteria, risk factors, and clinical outcomes, with particular attention to variations across geographic regions, surgical types, the span of time, and national economic statuses.

METHODS

A comprehensive search of Pubmed, Embase, OVID, Web of Science (WOS), Medline, and Cochrane Controlled Register of Trials (CENTRAL) was conducted from inception to 30 September 2024. Studies meeting all the following inclusion criteria were enrolled: 1) Population: neonates aged ≤ 30 days; 2) Disease: postoperative AKI diagnosed per KDIGO, pRIFLE, AKIN, nKDIGO, or others; 3) Study design: prospective/retrospective cohort studies or case-control studies; 4) Reporting data on postoperative incidence of AKI. The pooled proportion (along with 95% confidence intervals [CI]) of postoperative AKI was calculated. We also calculated pooled odds ratios (95% CI) for all-cause mortality in neonates with postoperative AKI when compared with those without AKI.

RESULTS

A total of 69 studies (10,519 cases) were included in the meta-analysis. The pooled incidence of postoperative AKI in neonates was 37% (95%CI 32-42, I = 96.4%, P<0.01), with a wide variability ranging from 0.0% to 74.8%. Several risk factors were identified, including lower preoperative or intraoperative urinary output, lower preoperative serum creatinine (SCr)/higher maximum postoperative SCr, elevated vasoactive inotrope score (VIS)/hypotension, younger corrected gestational age, prolonged cardiopulmonary bypass (CPB) duration, hypothermia, sepsis, and preoperative ventilation. Furthermore, 28 studies involving 6714 patients reported data on AKI-associated mortality with an overall incidence of 8.2%. Neonates who developed postoperative AKI had 3.3 times higher odds of mortality as compared to those without this complication.

CONCLUSIONS

Postoperative AKI affects one-third of neonates, and AKI-associated mortality remains high. Future efforts should focus on developing earlier and more sensitive detection methods.

SYSTEMATIC REVIEW REGISTRATION NUMBER

This meta-analysis was registered on https://www.crd.york.ac.uk/prospero/ with the registration number CRD 42024602820 on October 29, 2024.