Recurrent acute kidney injury in hospitalized adults: incidence, risk factors, and outcomes-a systematic review and meta-analysis.

BACKGROUND

Acute kidney injury (AKI) is a sudden decline in kidney function associated with chronic kidney disease (CKD), recurrent AKI, and increased mortality. Identifying risk factors is essential for early detection and prevention of recurrence.

OBJECTIVES

To update findings on the incidence, risk factors, and outcomes of recurrent AKI.

METHODS

A systematic search of PubMed, Scopus, Ovid MEDLINE, Virtual Health Library, Web of Science, and Google Scholar identified studies on recurrent AKI risk factors in hospitalized adults (Feb 2018-June 2024). Study quality was assessed using the Newcastle-Ottawa Scale. Data were extracted into Excel and analyzed with Comprehensive Meta-Analysis software. The protocol was registered in PROSPERO (CRD42024572504).

RESULTS

Seven studies (n = 160,898) were included. Pooled incidence of recurrent AKI was 22.8 % (95 % CI: 0.19-0.27). Continuous risk factors included higher blood urea nitrogen (MD = 2.30, 95 % CI: 1.14-3.46), lower hemoglobin (MD = -5.4, 95 % CI: -7.4 to -3.4), and higher baseline serum creatinine (MD = 11.5, 95 % CI: 3.5-19.5). Categorical risk factors included male sex, diabetes, and cardiovascular, liver, cerebrovascular, and respiratory diseases. Recurrent AKI was associated with higher mortality (OR = 2.81, 95 % CI: 1.77-4.47) and a slightly longer hospital stay (MD = 1.01 days, 95 % CI: 0.89-1.12). Evidence of potential publication bias was detected for mortality and hypertension. Meta-regression identified publication year as a source of heterogeneity (p = 0.004).

CONCLUSIONS

Recurrent AKI is common in hospitalized adults and linked to poor outcomes. Early risk identification and structured post-discharge monitoring may reduce recurrence and improve outcomes.