Supplementary Material for: Tachycardia and acute kidney injury among critically ill patients with sepsis: a prospective observational study

Introduction: Tachycardia caused by sympathetic overactivity impairs myocardial function and raises septic patient mortality. This study examined whether tachycardia is associated with acute kidney injury (AKI) period-prevalence among critically ill patients with and without sepsis.
Methods: In 328 patients (119 sepsis and 209 non-sepsis) admitted to our intensive care unit (ICU), we assessed heart rate at ICU admission, plasma neutrophil gelatinase-associated lipocalin (NGAL) and N-terminal pro-B-type natriuretic peptide, and urinary L-type fatty acid-binding protein and N-acetyl-β-D-glucosaminidase (NAG) at 0 and 48 hours after admission. Tachycardia was defined as a heart rate of above 100 beats/min.
Results: Tachycardia was independently correlated with AKI prevalence during the first week after ICU admission in the septic patients, but not in the non-septic patients. A dose-dependent increase in AKI period-prevalence was observed across ascending heart rate ranges. Furthermore, we discovered a dose-dependent increase of renal biomarker-positive patients regarding plasma NGAL and urinary NAG over increasing heart rate ranges 48 hours after admission.
Conclusion: The findings revealed an independent relationship between tachycardia and AKI prevalence during the first week of ICU in septic patients. Heart rate was found to have a dose-dependent effect on AKI prevalence and renal insult monitored by biomarkers.