INCIDENCE AND PREDICTORS OF ACUTE KIDNEY INJURY AMONG HOSPITALIZED MEDICAL PATIENTS AT AYUB TEACHING HOSPITAL: A PROSPECTIVE COHORT STUDY

Abstract

Background: Acute kidney injury (AKI) is a common complication among hospitalized patients and is associated with prolonged hospitalization, increased mortality and persistent renal dysfunction. However, there is limited prospective evidence regarding the incidence and predictors of incident AKI among general medical inpatients in Pakistan. This study aimed to determine the incidence of AKI and identify factors independently associated with its development among adult medical inpatients at a tertiary-care hospital. Methods: A hospital-based prospective cohort study was conducted in the medical units of Ayub Teaching Hospital, Abbottabad, Pakistan, from 5 June 2025 to 5 December 2025. Adult patients admitted to the medical units who were free of AKI at enrolment were consecutively recruited and followed throughout hospitalization. Patients with AKI at admission, end-stage kidney disease or other predefined exclusion criteria were excluded. AKI was defined and staged according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Baseline demographic, clinical and laboratory characteristics and relevant in-hospital exposures were recorded prospectively. Univariable logistic regression was performed to assess crude associations, followed by multivariable logistic regression to identify independent predictors of incident AKI. Associations were reported as odds ratios (ORs) with 95% confidence intervals (CIs). Results: Of 471 patients assessed for eligibility, 48 were excluded and 423 patients were enrolled in the cohort. During hospitalization, 92 patients developed incident AKI, giving an incidence of 21.7%, while 331 (78.3%) remained free of AKI. Most AKI episodes developed after the first 48 hours of hospitalization (73.9%), with a median time to AKI of 4 days (IQR 3–7). Stage 1 AKI was the most frequent category (57.6%), followed by Stage 2 (27.2%) and Stage 3 (15.2%). On multivariable analysis, chronic kidney disease (adjusted OR [aOR] 2.71, 95% CI 1.31–5.60; p=0.007), baseline eGFR <60 mL/min/1.73 m² (aOR 4.36, 95% CI 2.12–8.96; p<0.001), admission systolic blood pressure <90 mmHg (aOR 2.69, 95% CI 1.18–6.13; p=0.018), dehydration at admission (aOR 2.01, 95% CI 1.10–3.67; p=0.023), sepsis during hospitalization (aOR 2.34, 95% CI 1.40–3.92; p=0.001), hypotension during hospitalization (aOR 2.51, 95% CI 1.35–4.67; p=0.004), and exposure to potentially nephrotoxic medications (aOR 1.71, 95% CI 1.01–2.91; p=0.046) were independently associated with incident AKI. Patients who developed AKI had longer hospital stays, higher rates of ICU transfer and in-hospital mortality, and greater frequency of persistent renal dysfunction at discharge. Among patients with AKI, increasing disease severity was associated with greater ICU utilization, kidney replacement therapy, mortality and longer hospital stay. Conclusion: Incident AKI developed in approximately one-fifth of adult medical inpatients who were free of AKI at enrolment. Reduced baseline renal reserve, hypotension, dehydration, sepsis and potentially nephrotoxic medication exposure were independently associated with its development. Early identification of high-risk patients and continued monitoring of haemodynamic status, hydration, infection and medication exposure may provide practical opportunities for earlier recognition and prevention of AKI in general medical wards. Further multicentre prospective studies in Pakistan are needed to confirm these findings and evaluate targeted preventive strategies.