Incidence and Predictors of Acute Kidney Injury Among Postoperative Cardiac Surgery Patients in Tanzania.

INTRODUCTION

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a severe postoperative complication linked to increased morbidity and mortality. Data on the incidence and predictors of CSA-AKI in sub-Saharan Africa, including Tanzania, are limited. This study aimed to determine the incidence and predictors of AKI in patients who underwent cardiac surgery at Tanzania's National Cardiac Institute.

METHODS

This prospective study included 177 patients. AKI was defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria based on serum creatinine (SCr) changes at 24, 48, and 72 h postoperatively. The patients' clinical profiles were collected and analyzed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA). Chi-square tests and modified Poisson regression were used to identify associated factors at 95% confidence intervals (CIs), with P < 0.05.

RESULTS

The prevalence of postoperative AKI was 53%, with the majority of patients presenting with AKI stage I (72.9%). In the multivariable analysis, diabetes mellitus (Adjusted Prevalence Ratio (aPR )1.32, 95% CI 1.02-1.70; P = 0.038), American Society of Anesthesiologists (ASA) IV status (aPR 1.39, 95% CI 1.10-1.76; P = 0.007), blood transfusion (transfusion: aPR 3.63, 95% CI 1.15-11.41; P = 0.027), triple components (aPR 3.41, 95% CI 1.08-10.78; P = 0.037), and prolonged cardiopulmonary bypass (CPB) time of 181-240 min (aPR 3.53, 95% CI 1.51-8.25; P = 0.004) and > 240 min (aPR 3.80, 95% CI 1.57-9.18; P = 0.003) were independent predictors of AKI. Female sex was independently associated with a lower prevalence of AKI (aPR 0.66, 95% CI 0.50-0.88; P = 0.004). Patients who developed AKI had significantly longer stays in the intensive care unit (ICU) (aPR 2.39, 95% CI 1.39-4.12; P = 0.002).

CONCLUSION

The prevalence of CSA-AKI is remarkably high in this setting, posing a significant clinical burden. Key preoperative and intraoperative predictors were also identified. These results reinforce the importance of perioperative patient optimization, strategies to minimize CPB exposure, transfusion practice optimization, and surveillance of high-risk patients.