Urea Reduction in Acute Kidney Injury and Mortality Risk.

INTRODUCTION: Urea is a toxin present in acute kidney injury (AKI). We hypothesize that reduction in serum urea levels might improve clinical outcomes. We examined the association between the reduction in urea and mortality. METHODS: Patients with AKI admitted to the Hospital Civil de Guadalajara were enrolled in this retrospective cohort study. We create 4 groups of urea reduction ratio (UXR) stratified by their decrease in urea from the highest index value in comparison to the value on day 10 (0%, 1-25%, 26-50%, and >50%), or at the time of death or discharge if prior to 10 days. Our primary endpoint was to observe the association between UXR and mortality. Secondary observations included determination of which types of patients achieved a UXR >50%, whether the modality of kidney replacement therapy (KRT) effected changes in UXR, and if serum creatinine (sCr) value changes were similarly associated with patient mortality. RESULTS: A total of 651 AKI patients were enrolled. The mean age was 54.1 years, and 58.6% were male. AKI 3 was present in 58.5%; the mean admission urea was 154 mg/dL. KRT was started in 32.4%, and 18.9% died. A trend toward decreased risk of death was observed in association with the magnitude of UXR. The best survival (94.3%) was observed in patients with a UXR >50%, and the highest mortality (72.1%) was observed in patients achieving a UXR of 0%. After adjusting for age, sex, diabetes mellitus, CKD, antibiotics, sepsis, hypovolemia, cardio-renal syndrome, shock, and AKI stage, the 10-day mortality was higher in groups that did not achieve a UXR of at least 25% (OR: 1.20). Patients achieving a UXR >50% were most likely initiated on dialysis due to a diagnosis of the uremic syndrome or had a diagnosis of obstructive nephropathy. Percentage change in sCr was also associated with increased mortality risk. CONCLUSIONS: In our retrospective cohort of AKI patients, the percent decrease in UXR from admission was associated with a stratified risk of death. Patients with a UXR >25% had the best associated outcomes. Overall, a greater magnitude in UXR was associated with improved patient survival.

Serum Potassium Trajectory during Acute Kidney Injury and Mortality Risk.

BACKGROUND: The association between potassium (sK) level trajectory and mortality or the need for kidney replacement therapy (KRT) during acute kidney injury (AKI) has not been adequately explored. METHODS: In this prospective cohort, AKI patients admitted to the Hospital Civil de Guadalajara were enrolled. Eight groups based on the sK (mEq/L) level trajectories during 10 days of hospitalization were created (1) normokalemia (normoK), defined as sK between 3.5-5.5; (2) hyperkalemia to normoK; (3) hypokalemia to normoK; (4) fluctuating potassium; (5) persistent hypoK; (6) normoK to hypoK; (7) normoK to hyperK; (8) persistent hyperK. We assessed the association of sK trajectories with mortality and the need for KRT. RESULTS: A total of 311 AKI patients were included. The mean age was 52.6 years, and 58.6% were male. AKI stage 3 was present in 63.9%. KRT started in 36% patients, and 21.2% died. After adjusting for confounders, 10-day hospital mortality was significantly higher in groups 7 and 8 (OR, 1.35 and 1.61, p < 0.05, for both, respectively), and KRT initiation was higher only in group 8 (OR 1.38, p < 0.05) compared with group 1. Mortality in different subgroups of patients in group 8 did not change the primary results. CONCLUSION: In our prospective cohort, most patients with AKI had alterations in sK+. NormoK to hyperK and persistent hyperK were associated with death, while only persistent hyperK was correlated with the need for KRT.