A Study of Incidence of AKI in Critically Ill Patients

Background: There have been many studies to estimate the incidence of acute kidney injury (AKI) in critically ill patients. However, results were variable due to the non-usage of uniform criteria and retrospective design of most studies. There are no new studies from the developing countries looking at AKI in these patients since adoption of uniform Acute Kidney Injury Network (AKIN) criteria.

Methods: In this prospective observational study from a tertiary care hospital in India, we enrolled 100 consecutively admitted critically ill patients and followed them during hospital stay. AKI was defined by AKIN criteria. Both the groups of patients, those who developed AKI and those who did not develop AKI, were then followed during the course of their hospital stay.

Results: AKI occurred in 33 patients with an incidence rate of 17.3 per person year. Thirty-one out of 33 (93.9%) patients died in the AKI group, whereas 31 out of 67 (53.7%) patients died in the non-AKI group. Independent risk factors for AKI were older age (adjusted relative risk (RR) = 4.42, 95% CI = 2.57-5.23), septic shock (adjusted RR = 2.82, 95% CI = 1.43-3.80), prolonged duration of mechanical ventilation (adjusted RR = 2.35, 95% CI = 1.09-3.6), higher acute physiology and chronic health evaluation II (APACHE II) score (adjusted RR = 2.74, 95% CI = 1.28-4.13), and higher sequential organ failure assessment (SOFA) score (adjusted RR = 2.53, 95% CI = 1.04-4.08). Development of AKI was an independent risk factor for mortality (adjusted RR = 1.76, 95% CI = 1.25-1.84).

Conclusion: Older patients, those with septic shock, and those requiring prolonged mechanical ventilation had increased risk for AKI. AKI was an independent predictor of mortality.