Incidence, Predictors, and Clinical Outcomes of Acute Kidney Injury in Critically Ill Patients: A Retrospective Study

BackgroundAcute kidney injury (AKI) is a frequent and serious complication among critically ill patients and is associated with prolonged hospitalization, increased need for organ support, and higher mortality. ObjectiveThe objective of the study is to determine the incidence of AKI among critically ill patients, identify its independent predictors, and evaluate its association with major clinical outcomes. MethodsThis retrospective observational study was conducted at Services Hospital, Lahore, Pakistan, from June 2023 to June 2026 and included 261 adult critically ill patients.Demographic characteristics, comorbidities, clinical severity scores, laboratory parameters, treatment-related factors, and clinical outcomes were extracted from medical records. ResultsAKI developed in 102 of 261 patients, corresponding to an incidence of 39.1%.Among patients with AKI, 42 (41.2%)had Kidney Disease: Improving Global Outcomes (KDIGO) stage 1, 34 (33.3%) had stage 2, and 26 (25.5%) had stage 3 disease.Compared with patients without AKI, those with AKI had higher intensive care unit (ICU) mortality (35 (34.3%) vs. 19 (11.9%)), in-hospital mortality (41 (40.2%) vs. 24 (15.1%)), and renal replacement therapy requirement (21 (20.6%) vs. 0 (0.0%)), as well as longer ICU and hospital stays and longer duration of mechanical ventilation (all p < 0.001).Factors independently associated with AKI included chronic kidney disease (adjusted odds ratio (aOR) 3.12, 95% confidence interval (CI) 1.34-7.28),vasopressor support at ICU admission (aOR 2.86, 95% CI 1.49-5.50),sepsis or septic shock (aOR 2.74, 95% CI 1.48-5.08),mechanical ventilation at ICU admission (aOR 2.09, 95% CI 1.08-4.04),increasing serum lactate (aOR 1.31, 95% CI 1.10-1.57),higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score (aOR 1.09, 95% CI 1.04-1.14),and increasing age (aOR 1.03, 95% CI 1.01-1.05). ConclusionAKI affected more than one-third of critically ill patients and was associated with a greater observed clinical burden, including higher mortality, greater need for renal replacement therapy, prolonged mechanical ventilation, and longer ICU and hospital stays.Chronic kidney disease, sepsis or septic shock, vasopressor support at ICU admission, mechanical ventilation at ICU admission, higher serum lactate, higher APACHE II score, and increasing age were independently associated with AKI.Because clinical outcome comparisons were unadjusted, the observed differences in mortality, mechanical ventilation duration, and length of stay do not establish AKI as an independent determinant of these outcomes.