A Prospective International Multicenter Study of AKI in the Intensive Care Unit

Abstract

Background and objectives: AKI is frequent and is associated with poor outcomes. There is limited information on the epidemiology of AKI worldwide. This study compared patients with AKI in emerging and developed countries to determine the association of clinical factors and processes of care with outcomes.

Design, setting, participants, & measurements: This prospective observational study was conducted among intensive care unit patients from nine centers in developed countries and five centers in emerging countries. AKI was defined as an increase in creatinine of ≥0.3 mg/dl within 48 hours.

Results: Between 2008 and 2012, 6647 patients were screened, of whom 1275 (19.2%) developed AKI. A total of 745 (58% of those with AKI) agreed to participate and had complete data. Patients in developed countries had more sepsis (52.1% versus 38.0%) and higher Acute Physiology and Chronic Health Evaluation (APACHE) scores (mean±SD, 61.1±27.5 versus 51.1±25.2); those from emerging countries had more CKD (54.3% versus 38.3%), GN (6.3% versus 0.9%), and interstitial nephritis (7.0% versus 0.6%) (all P<0.05). Patients from developed countries were less often treated with dialysis (15.5% versus 30.2%; P<0.001) and started dialysis later after AKI diagnosis (2.0 [interquartile range, 0.75-5.0] days versus 0 [interquartile range, 0-5.0] days; P=0.02). Hospital mortality was 22.0%, and 13.3% of survivors were dialysis dependent at discharge. Independent risk factors associated with hospital mortality included older age, residence in an emerging country, use of vasopressors (emerging countries only), dialysis and mechanical ventilation, and higher APACHE score and cumulative fluid balance (developed countries only). A lower probability of renal recovery was associated with residence in an emerging country, higher APACHE score (emerging countries only) and dialysis, while mechanical ventilation was associated with renal recovery (developed countries only).

Conclusions: This study contrasts the clinical features and management of AKI and demonstrates worse outcomes in emerging than in developed countries. Differences in variations in care may explain these findings and should be considered in future trials.

Keywords: acute renal failure; epidemiology and outcomes; nephrology.

Figure 1.

Enrollment of study patients. ICU, intensive care unit.

Figure 2.

Causes of AKI. The causes of AKI are nonexclusive. Intravascular fluid losses included hemorrhage, burns, and hypovolemia due to other causes. Increased vascular capacity included sepsis and other causes. Extracorporeal fluid losses included vomiting, diarrhea, and diabetes insipidus, while vascular causes included artery/vein thrombosis, emboli, or trauma. P values for the difference between developed and emerging countries for each cause of AKI are, respectively, as follows: prerenal, P<0.001; intravascular fluid losses, P=0.004; sepsis, P<0.001; cardiac failure, P<0.001; liver diseases, P=0.06; extracorporeal fluid losses, P=0.02; acute tubular necrosis, P<0.001; multisystemic, P<0.01; contrast-induced, P=0.03; interstitial nephritis, P<0.001; GN, P<0.001; obstruction, P=0.003; vascular, P=0.31. With the Bonferroni correction, P≤0.004 represents a significant difference. Other causes were unknown or undetermined.