Incidence of acute kidney injury and associated mortality in Nigeria: systematic review and meta-analysis

The burden of acute kidney injury (AKI) in low- and middle-income countries is frequently underestimated, often due to limited diagnostic resources and underreporting. Information about the burden of AKI would help inform the implementation of health policies and improve the allocation of health resources aimed at enhancing patient outcomes. This study determined the pooled incidence of AKI and associated mortality in Nigeria. A systematic search of PubMed, African Journals Online (AJOL), and Google Scholar was conducted to identify relevant studies on AKI in both adult and paediatric populations in Nigeria between 1980 and 2024. Case reports, case series, and abstracts without full text on AKI were excluded. The pooled incidence of AKI and the associated all-cause mortality rate were estimated using meta-analytic methods. The Joanna-Briggs scoring was used for risk bias assessment. The study protocol was registered with PROSPERO (CRD42024620822). The initial systematic literature search identified 384 articles from which 44 eligible hospital-based studies involving 123,324 participants were included. The median age of the study participants was 31.1 years, and the median proportion of females was 42.9%. The overall pooled incidence of AKI in this study was 15.0% [CI: 12.0–18.0%], based on 44 studies, with I 2 = 99.3% and p < 0.001. The pooled incidence of AKI in the adult and paediatric populations was 18.0% [CI: 12.0%-25.0%, n = 22 studies, I 2 = 99.0%, p < 0.001], and 12.0% [CI: 9.0%-15.0%, n = 20 studies, I 2 = 99.2%, p < 0.001], respectively. The leading aetiologies of AKI were hypovolaemia (32.3%), sepsis (28.8%), malaria (12.8%), and acute glomerulonephritis (11.5%). The most common criteria used in diagnosing AKI were those outlined in the Kidney Disease Improving Global Outcomes (KDIGO) guidelines in 27 studies (58.7%). There was a significant difference in the pooled incidence of AKI with the different diagnostic criteria ( p < 0.001). About 46.0% of the AKI population presented in stage 3, and haemodialysis was the kidney replacement therapy option in 76.2% of those dialysed. The overall pooled all-cause mortality rate in patients with AKI was 26.0% [CI: 19.0%-33.0%], n = 34 studies, I 2 = 92.6%, p < 0.001, 34 studies. The review included only hospital-based studies, and high heterogeneity was observed in the studies. Therefore, the results should be interpreted with caution. The incidence and mortality rates of AKI in Nigeria are high. Prompt and adequate treatment of the underlying and preventable causes may reduce the disease burden.