Outcomes of acute kidney injury in critically ill adults with tropical acute febrile illness: Prospective observational study.

BACKGROUND

Tropical acute febrile illness (TAFI) is a major illness with a large number of intensive care unit (ICU) admissions in tropical regions. It is frequently complicated by acute kidney injury (AKI) and associated poor outcomes. The data on the predictors of outcomes, in terms of in-hospital mortality and renal outcomes, amongst critically-ill TAFI patients from our region remain limited.

AIM: To evaluate the clinical profile and outcomes of AKI amongst critically-ill TAFI patients and to identify the factors associated with in-hospital mortality.

METHODS

This prospective observational cohort study was conducted amongst the patients admitted in ICU at a tertiary care teaching hospital in the state of Rajasthan (India) between June and September 2025. Adult patients (aged ≥ 18 years), with laboratory-confirmed TAFI and AKI diagnosed using AKI network criteria, were included in the study. Demographic, clinical, laboratory, and organ-support variables were recorded. The primary outcome was all-cause in-hospital mortality while the secondary outcomes included renal recovery at the time of discharge and a composite net negative outcome (NNO) (defined as in-hospital mortality or persistent renal dysfunction during discharge). Univariate and exploratory multivariable logistic regression analyses were conducted to identify the predictors of the outcomes.

RESULTS

The data collected from a total of 68 critically-ill TAFI patients with AKI was analyzed. Their median age was 52 years while 37 (54.4%) were females. Scrub typhus 43 (63.24%) was found to be the most common etiology, followed by dengue 9 (13.24%). AKI stage I was found to be the most frequent (37; 54.4%) at ICU admission, while 19 (27.94%) required renal replacement therapy. Overall, the in-hospital mortality was 8 (11.8%) while NNO was observed in 23 (33.8%) patients. In terms of multivariable analysis, higher APACHE II scores and lower arterial oxygen tension at admission independently predicted the mortality. Dialysis requirement was found to be a strong predictor of NNO (odds ratio 21.95), along with hypoxemia and greater illness severity.

CONCLUSION

AKI in critically-ill TAFI patients has the modest mortality yet it results in substantial morbidity and incomplete renal recovery outcomes. Early hypoxemia, illness severity, and the need for dialysis are the key predictors of adverse outcomes. The study findings emphasize the importance of a comprehensive severity assessment beyond the existing creatinine-based AKI staging method.