Outcome and Determining Characteristics of ICU Patients with Acute Kidney Injury in a Low-Income Country, a Multicenter Experience

Background: Acute kidney injury (AKI) is a disease that affects millions of people globally making it a major public health concern. It is defined as an abrupt decrease in kidney function that occurs within ours affecting both the structure and functionality of the kidneys.
The outcome of AKI and the determinants in Nigeria are largely unknown. This study aimed to describe the determining factors of the outcome of AKI patients admitted into the ICU of three tertiary health institutions in Northeast Nigeria.
Methods: The study is a prospective multicentered observational study of the patients admitted into the ICU in three tertiary health institutions from January 2022 to December 2023. KDIGO criteria was used to define AKI. The outcome of the study was to determine survivors among the patients admitted into the ICU with AKI or developed AKI while in ICU and also the determinants of mortality. A chi-square test was done to determine the association between the dependent variable (patient outcome) and the independent variables. To determine the predictors of patient outcomes, a regression analysis was done. The sociodemographic data of the patients admitted during these periods were studied in addition to Acute Physiology and Chronic Health Evaluation (APACHE) II, Kidney Disease: Improving Global Outcomes (KDIGO), Average length of stay in the ICU, Admitting/referring ward (Obstetrics, Gynae, Medical, Surgical or Emergency unit), Ability to afford care (out of pocket payment, social welfare or through Health insurance Scheme, Co-morbidity (presence or absence of comorbidity), Interventions done while in ICU (use of vasopressors and inotropes, mechanical ventilation (MV) support and renal replacement therapy (RRT) and outcome (discharge to the wards or mortality).
Results: Of 1494 patient records screened, 464 met the inclusion criteria. The overall incidence of AKI was 57%. About 53% were females, the mean age was 42.2 years, and 81% of the patients had a normal BMI (18.5 – 24.9). About 40% of the patients had APACHE II scores ≥ 29%. More than three-quarters (79.5%) of the patients paid for their health care expenditure out-of-pocket. Most patients (72%) were from the Medical and Gynae/Ward. Mortality was highest (54.2%) among patients who were brought into the ICU from the Medical ward. Most patients admitted were KDIGO I (44.3%) followed by KDIGO II (35.1%). Among the patients, 61.2% present with one or more comorbidity. Mortality was higher (50%) among those with comorbidity compared to 13.6% among those without comorbidity. Mortality was lowest among patients who stayed in the ICU between 8-14 days compared to those who stayed > 2 weeks. Most of the patients (72%) were from the Medical and Gynae/Ward. Mortality was highest (54.2%) among patients who were brought into the ICU from the Medical ward followed by those brought in from the Obstetric and Gynecological ward (20.4%). An association was found between the intervention received in the ICU and the outcome, which was found to be statistically significant (p < 0.001). A regression analysis was done to determine the predictors of patients’ outcomes admitted in the ICU. The results showed that APACHE II score greater than 10 (p-value < 0.001), presence of comorbidities (p = 0.031) and intervention which included a combination of Vasopressors, mechanical ventilation and RRT (p < 0.01) are the predictors of patients’ outcome. The regression model is valid (X2 = 469.894, df = 24, p < 0.001) and it fits the sample as shown by the Hosmer and Lemeshow test (X2 = 7.749, p = 0.45, df = 8,). It also shows that the predictors account for 92% of patients’ outcomes (Nagelkerke R2 = 0.92).
Conclusions: Our study revealed that the presence of comorbidity, high APACHE II score, and the need for interventional supports including both mechanical ventilatory and ionotropic, were found to be strong mortality predictors in patients with AKI.