#746 Lactic acidosis in patients with acute kidney injury treated with renal replacement therapy in intensive care unit

Abstract

Abstract Background and Aims Lactic acidosis (LA) is the most common cause of metabolic acidosis in hospitalised patients. LA is frequent in intensive care unit (ICU) patients with acute kidney injury (AKI) treated with renal replacement therapy (RRT). The aim of our study was to analyse the impact of LA on mortality. Method We conducted a retrospective observational study in a tertiary care hospital with a 12-bed ICU. During the study period of 4 years before the COVID pandemic, 2939 patients were admitted to the ICU, 503 patients were diagnosed with AKI and 210 of them required RRT. Due to missing data, we retrospectively analysed only 176 patients. LA was defined as a serum lactate concentration above 4 mmol/L on admission to the ICU. Demographic data, comorbidities, laboratory data at ICU admission and 30-day survival after ICU admission were obtained from the medical record. Survival was estimated using the Kaplan-Meier method, and factors associated with 30-day mortality were assessed in a Cox regression. Results The mean age of patients was 63.4±12.9 years, and 68.2% were men. Sixty-five (36.9%) of patients had LA. The prevalence of comorbidities prior to admission and baseline laboratory values are shown in Table 1. All patients were treated with RRT, 137 (77.8%) with continuous RRT and 39 (22.2%) with intermittent hemodialysis. The mean ICU stay was 14.6 ± 12 days, and 114 (64.8%) patients died during the observational period of 30 days. A Kaplan-Meier survival analysis showed that the survival was statistically significantly lower (log-rank; p = 0.027) in the group of patients with LA (Fig. 1). Univariate Cox regression analysis showed that LA was a significant predictor of 30-day survival (HR 1.51; 95% CI 1.038-2.197; p = 0.031). In the multivariate Cox regression analysis, which included age, gender, diabetes, hypertension, LA and C-reactive protein, only age (HR 1.029; 95% CI 1.011-1.046; p = 0.001) and LA (HR 1.515; 95% CI 1.030-2.228; p = 0.035) were independent predictors of mortality. Conclusion LA on ICU admission is an independent, highly prognostic factor for death within 30 days of admission in patients with AKI treated with RRT.