Back
Introduction:
Recent projections show that Brazil will have the fifth oldest population in the world by 2030. The incidence of kidney diseases (both acute and chronic) among the elderly population varies according to the group analyzed. However, previous studies suggest that the elderly are more susceptible to the development of acute kidney injury (AKI) and that renal replacement therapy (RRT) in these individuals does not prolong survival, being associated instead with a higher mortality rate.
Methods:
This is a retrospective study, in which data was collected from electronic medical records. The selection included individuals over 80 years old, admitted to the “Hospital do Servidor Público do Estado de São Paulo” from January 2022 to July 2023, with impaired renal function and who were followed up by the nephrology service. The individuals were divided into two groups: those undergoing renal replacement therapy (RRT) and those maintained on conservative therapy. The patients were monitored by the nephrology service during hospitalization until hospital discharge or death. Laboratorial and clinical data were analyzed until the outcome of each patient. Constant variables were summarized as median and interquartile range while categorical variables were summarized as percentages. The comparison within constant variables was performed by using the Mann-Whitney test. The analysis of the categorical variables was made by either using the Chi-square test or the Fisher's exact test. Variables that had p< 0.10 in the univariate analysis were submitted to a multivariate analysis by bimodal logistic regression. The adjusted odds ratio (OR) and 95% confidence interval (CI) were calculated. All statistical tests were 2-tailed and statistical significance was set at p < 0.05.
Results
In total, 609 patients were included, being that 128 patients (21%) underwent RRT while 481 were kept on conservative therapy. The overall mortality rate of the studied population was 271 patients (44.4%), with a higher incidence in the RRT group (71.1% versus 37.4%; p < 0.001). The RRT group showed less renal recovery at hospital discharge and were followed up for a longer period of time when compared to the conservative group (table 1 shows the comparison between these groups). The multivariate analysis (table 2) shows that the RRT group was younger than the conservative group, had a higher prevalence of hypertension and had a lower glomerular filtration rate prior to hospitalization. Furthermore, the RRT group had a greater chance of presenting an KDIGO 3 AKI other than an KDIGO 1 AKI by the time the nephrology service was called. During the nephrology follow-up, patients who underwent RRT also had a higher risk of requiring mechanical ventilation (MV).
Conclusion:
The data suggest that the oldest-old patients who underwent RRT had a higher mortality rate than those maintained on conservative therapy. One must take into account the fact that the RRT group had multiple associated severity factors, such as KDIGO 3 AKI and the need for MV. The necessity of RRT seemed to have a negative impact on the mortality of the population over 80 years old. These factors must be considered when recommending RRT to elderly patients.