Long-term outcomes following acute kidney injury in individuals with pre-existing chronic kidney disease: a systematic review and meta-analysis.

Abstract

Background: Acute kidney injury (AKI) is linked to a heightened risk of progressing to chronic kidney disease (CKD) in individuals exhibiting normal baseline kidney function. However, the extent of such association in individuals with pre-existing CKD or renal impairment has been insufficiently investigated. Hence, we performed an extensive literature review and meta-analysis of the literature.

Methods: Articles published on PubMed, Embase, and Cochrane (up to December 2, 2024) were searched for post-hoc analyses/sub-analysis of randomized controlled trials (RCTs) or observational studies that evaluated the association between AKI insult and long-term progression or overall death in individuals with pre-existing CKD or kidney dysfunction. All selected articles incorporated odds ratio (OR), hazard ratio (HR), or relative risk (RR) statistics along with data for assessing the association. Pooled RRs and 95% confidence intervals (CI) were derived utilizing random-effects models, notwithstanding the heterogeneity evaluated by I² statistic. The protocol was not registered at PROSPERO or SRDR.

Results: Ultimately, 39 studies with an aggregate of 332,198 participants were determined to be eligible for inclusion. Of them, 28 studies were included in an analysis of CKD progression risk, and 27 studies were incorporated in the analysis of all-cause mortality. Individuals who have experienced AKI were at  elevated risk for progression of CKD (HR 2.36, 95% CI 1.96-2.85) and all-cause mortality (1.58, 1.38-1.81) with significant heterogeneity. Subgroup and sensitivity analyses supported the findings. For both outcomes, gradient of risk was observed as the AKI stage increased. For all-cause mortality, the risk magnitude was modified by the clinical environment.

Conclusions: A history of AKI is correlated with heightened risks of CKD progression and overall death in patients with pre-existing CKD. Future research should be focused on the frequency of AKI episodes, the restoration of kidney function according to the different timeframe, and the impact of concomitant proteinuria on prognosis in these patients.