Detailed clinical history was taken, and clinical examination was performed for all the enrolled patients. Following investigations was performed for all the patients at the time of admission: complete blood count (CBC), liver function test (LFT), renal function test (RFT), chest X-ray, ultrasound abdomen, fluid intake, and urine output measurement, urine routine examination, urine and blood culture and sensitivity, and arterial blood gas analysis (ABG). Subsequent serum creatinine levels were assessed during the hospital stay. Acute Kidney Injury (AKI) was categorized as per AKI-KDIGO severity classification. The etiology of Acute Kidney Injury (AKI) was also recorded. Whenever the patient requires renal replacement therapy, ionotropic support, or ventilator support, was documented. APACHE II scores were calculated at the time of admission to ICU or on the day of acute kidney injury. Patients were followed until discharge from the hospital or occurrence of in-hospital mortality. All data was collected and recorded in a pretested semi-structured questionnaire.