MO838: Urgent-Start Haemodialysis in the Elderly Patients: Patterns and Predictors of 1-Year Mortality
Authors: Fraga Dias Bruno , Fernandes João , Sala Inês , Freitas Joana , Santos Lascasas Josefina , Malheiro Jorge , Cabrita António 
Published: May 2022

Abstract

BACKGROUND AND AIMS
The number of elderly patients starting haemodialysis is increasing as a result of an aging population and age-related increases in the incidence of chronic kidney disease.
Outcomes of elderly patients with end-stage kidney disease at urgent haemodialysis (UH) initiation are poorly studied. It is necessary to define predictors of adverse outcomes in these population.
The aim of this study was to evaluate patterns and predictors of 1-year mortality of urgent-start haemodialysis in elderly patients.

METHOD
This is an observational, retrospective study including all elderly patients (&gt;65 years) who started UH between 2014 and 2019. The follow-up period was 1 year after the start of UH. Demographic data, comorbidities, analytical parameters and vascular access were recorded.
We analyzed global mortality by Kaplan–Meier survival curves and predictors of mortality at 1 year by multivariable Cox regression. In a secondary evaluation, predictors of mortality at 1 year by specific cause were studied through competing-risks multivariable regression.

RESULTS
A total of 166 patients (75.5 ± 6.3 years) were included and 45 patients (27%) died at 1-year follow-up. One-year mortality rate was 33/100 person-years [95% confidence interval (95% CI): 25–44] with the highest mortality rate in the first trimester (48/100 person-years, 95% CI: 31–75) (Figure 1A).
The main cause of mortality was infection (mortality rate 14/100 person-years, 95% CI 9–22) followed by cardiovascular deaths (11/100 person-year, 95% CI 7–18) and cancer (5/100 person-years, 95% CI 2–11).
There was a significant difference in the Kaplan–Meier survival probability between the patients with CFS ≥ 5 and CFS &lt; 5 at 3 and 12 months (83% versus 98% and 59% versus 95%, respectively, P &lt; 0.001); we also found differences in survival between patients with serum albumin levels &lt; 3.2 g/dL and patients with serum albumin levels &gt;3.2 g/dL, at 3 and 12 months (81% versus 94% and 57% versus 84%, respectively, P &lt; 0.001) (Figure 2B and C).
Patients who died at 1 year of follow-up were later referred to nephrology (P = 0.031), had lower serum albumin levels (P = 0.001), had a higher Clinical Frailty score—CFS—(P &lt; 0.001) and a higher modified Charlson comorbility index—mCCI (P = 0.011).
The 1-year mortality predictors that we identified were: CFS ≥ 5 (HR = 10.185; P &lt; 0.001), mCCI ≥ 5 (HR = 2.190; P = 0.025), serum albumin levels &lt; 3.2 g/dL (HR = 2.194, P = 0.013) and referral to nephrologist 4 months before UH (HR = 2.220; P = 0.012). In the first trimester, only CFS ≥ 5 was a predictor of mortality (HR = 8.468; P = 0.041). On the other hand, between 4 and 12 months, the following predictors of mortality were documented: CFS ≥ 5 (HR = 12.386; P = 0.001), serum albumin levels &lt; 3.2 g/dL (HR = 2.420; P = 0.032) and body mass index (HR = 0.925; P = 0.027).
Predictors of 1-year infection-related death were CFS ≥ 5 (sHR = 9.809; P = 0.024) and serum albumin levels &lt; 3.2 g/dL (sHR = 4.258; P = 0.011). The predictors of cardiovascular-related death were CFS ≥ 5 (sHR = 8.150; P = 0.038) and ischemic coronary disease (sHR = 4.467; P = 0.009). The predictors of mortality by cancer were CFS ≥ 5 (sHR = 8.225; P = 0.032), serum albumin levels &lt; 3.2 g/dL (sHR = 4.408; P = 0.029) and diagnosis of cancer in the previous 5 years (sHR = 5.631; P = 0.003).

CONCLUSION
This study showed a high mortality rate in elderly patients who started UH, especially during the first 3 months. Infectious diseases were the main cause of mortality followed by cardiovascular diseases.
The CFS was a useful predictor of mortality in the global analysis and a predictor of mortality caused by infection, cancer or cardiovascular disease; all patients started UH, which can exacerbate the importance of frailty in defining outcomes.
Serum albumin is a predictor of mortality by infectious causes, possibly reflecting the inflammatory activity and malnutrition of these patients. The relationship between BMI and outcomes needs further evaluation.