Worsening or improving hypoalbuminemia during continuous renal replacement therapy is predictive of patient outcome: a single-center retrospective study

Abstract

Background: Hypoalbuminemia at the initiation of continuous renal replacement therapy (CRRT) is a risk factor for poor patient outcomes. However, it is unknown whether the patterns of changes in serum albumin levels during CRRT can be used to predict patient outcomes.

Methods: This retrospective study analyzed data that had been consecutively collected from January 2016 to December 2020 at the Third Affiliated Hospital. We included patients with acute kidney injury who received CRRT for ≥ 72 h. We divided the patients into four groups based on their serum albumin levels (albumin ≥ 3.0 g/dL or < 3.0 g/dL) at the initiation and termination of CRRT.

Results: The 793 patients in this study were categorized into the following albumin groups: persistently low, 299 patients (37.7%); increasing, 85 patients (10.4%); decreasing, 195 patients (24.6%); and persistently high, 214 patients (27.1%). In-hospital mortality rates were highest in the persistently low and decreasing groups, followed by the increasing and persistently high groups. The hazard ratio for in-hospital mortality was 0.481 (0.340-0.680) in the increasing group compared to the persistently low group; it was 1.911 (1.394-2.620) in the decreasing group compared to the persistently high group. The length of ICU stay was 3.55 days longer in the persistently low group than in the persistently high group.

Conclusions: Serum albumin levels changed during CRRT, and monitoring of patterns of change in serum albumin levels is useful for predicting in-hospital mortality and the length of ICU stay.

Keywords: Acute kidney injury; Albumin; Continuous renal replacement therapy; Hypoalbuminemia.

Fig. 1

Flow diagram of the study population

Fig. 2

Changes in serum albumin level during continuous renal replacement therapy in the four albumin groups: orange, persistently high; green, increasing; purple, decreasing; blue, persistently low. Numbers at the bottom of the figure indicate the number of data available for each group on each day

Fig. 3

A Hazard ratios for in-hospital mortality of the increasing group compared to the persistently low group (left), and the decreasing group compared to the persistently high group (right) stratified by age, sex, body mass index, diabetes, congestive heart failure, liver cirrhosis, chronic kidney disease, chronic obstructive pulmonary disease, sepsis, anuria, and SOFA score. B Kaplan–Meier survival analysis results of the four albumin change groups; orange, persistently high; green, increasing; purple, decreasing; blue, persistently low

Fig. 4

A The proportion of patients with a fluid reduction more than 2% of their initial body weight in the four albumin groups. B The proportion of patients with a fluid gain of more than 2% of initial body weight in the four albumin groups

Fig. 5

Changes in serum CRP levels during continuous renal replacement therapy in the four albumin groups: orange, persistently high; green, increasing; purple, decreasing; blue, persistently low. Numbers at the bottom of the figure show the number of data available for each group and each day