The characteristics of the older dialysis population—heterogeneity and another type of altered risk factor patterns

Intramuscular and abdominal fat measured by computed tomography and mortality of hemodialysis patients

BACKGROUND

In hemodialysis patients, high body mass index is associated with low mortality while abdominal obesity relates to increased mortality. We aimed to investigate the association between muscle mass, intramuscular fat and abdominal fat measured by abdominal computed tomography (CT), and mortality in this patients population.

METHODS

This two-center retrospective cohort study included hemodialysis patients who underwent abdominal CT between January 2013 and December 2018. Skeletal muscle mass index (SMI), muscle radiation attenuation (MRA) as an index of intramuscular fat, and visceral fat to subcutaneous fat ratio (VSR) were calculated using CT images at the third lumbar vertebral level. Multivariate Cox proportional hazards model was used to determine the independent predictors of all-cause, cardiovascular and non-cardiovascular mortalities.

RESULTS

The study included 344 patients (median age 71.0 years; female 33.7%), among whom 145 died during a median follow-up of 4.9 years-46 and 99 from cardiovascular and non-cardiovascular causes, respectively. Lower MRA [hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.58-0.87, P = .001] and higher VSR (HR 1.17, 95% CI 1.01-1.37, P = .04) were independently associated with higher all-cause mortality but not with lower SMI (HR 0.87, 95% CI 0.68-1.11, P = .26). Lower MRA (HR 0.51, 95% CI 0.35-0.73, P < .001) and higher VSR (HR 1.29, 95% CI 1.09-1.54, P = .003) were also associated with cardiovascular and non-cardiovascular mortality, respectively.

CONCLUSIONS

Intramuscular fat and abdominal fat as measured using abdominal CT in hemodialysis patients are stronger independent predictors of mortality than muscle mass.

Immunological features of ESRD patients undergoing hemodialysis of various ages

AIMS

To investigate the immunological characteristics of hemodialysis (HD) patients with end-stage renal disease (ESRD) of various ages, and the impact of age-related immune alterations on these patients, with a focus on peripheral T cells.

METHODS

From September 2016 to September 2019, HD patients were enrolled and followed prospectively for 3 years. Patients were divided into three groups based on their ages: < 45, 45 to 64, and ≥ 65. The distribution of T cell subsets in different age groups was investigated and compared. The effects of altered T cell subsets on overall survival were also investigated.

RESULTS

A total of 371 HD patients were enrolled. The reduced number of naive CD8+ T cells (P < 0.001) and increased number of EMRA CD8+ T cells (P = 0.024) were independently associated with the advanced age among all T cell subsets studied. Patient survival may be affected by numerical changes in naive CD8+ T cells. However, when HD patients were < 45 or ≥ 65 years, the reduction had no significant impact on survival. Only in HD patients aged 45 to 64 years, the number of naïve CD8+ T cells found to be insufficient but not deficient, identified as an independent predictor of poor survival.

CONCLUSIONS

The most significant age-related immune change in HD patients was a decrease in peripheral naive CD8+ T cells, which was an independent predictor of 3-year overall survival in HD patients aged 45 ~ 64 years.

Age-associated effects of intradialytic exercise on physical function and nutritional status in patients receiving ambulatory hemodialysis: A multicenter cohort study

INTRODUCTION

Intradialytic exercise is essential for improving physical function for older patients. This study aimed to examine the relationship between the effects of exercise therapy and aging.

METHODS

This multicenter cohort study included 1176 patients aged 40-89 years, who participated in an intradialytic exercise program, comprising stretching and resistance training, three times per week for 12 months. Isometric knee extension strength (IKES), 10-m walking speed, Short Physical Performance Battery (SPPB), and Geriatric Nutritional Risk Index (GNRI) were measured at baseline and after 12 months. The patients were divided according to age as follows: 40-59, 60-69, 70-79, and 80-89 years. A linear mixed-effects model examined the improvement within-group and between-control differences, as the 40-59 age group was the control group.

FINDINGS

The 40-59, 60-69, 70-79, and 80-89 age groups comprised 180, 317, 466, and 213 participants, respectively. Within-group differences, all the age groups significantly improved IKES and SPPB. The 10-m walking speed [0.02 (0.02) m/s] and GNRI [0.38 (0.33)] did not improved only in the 80-89 age group despite other age groups significantly improved. Between-control differences, IKES of the 70-79 age group [-0.24 (-0.42 to -0.06) %] was significantly lower improvement than control. GNRI of all the older groups were significantly smaller improvement than control (p < 0.05).

DISCUSSION

The older group demonstrated difficulty in improving walking ability and nutritional status compared with the younger groups. Clinicians need to consider the difference in effectiveness due to age and prescribe intradialytic exercises accordingly.

Mortality and Risk Factors in Very Elderly Patients Who Start Hemodialysis: Korean Renal Data System, 2016-2020

INTRODUCTION

The number of elderly patients with end-stage renal disease (ESRD) is increasing worldwide. However, decision-making about elderly patients with ESRD remains complex because of the lack of studies, especially in very elderly patients (≥75 years). We examined the characteristics of very elderly patients starting hemodialysis (HD) and the associated mortality and prognostic factors.

METHODS

Data were analyzed retrospectively using a nationwide cohort registry, the Korean Renal Data System. Patients who started HD between January 2016 and December 2020 were included and divided into three groups according to age at HD initiation (<65, 65-74, and ≥75 years). The primary outcome was all-cause mortality during the study period. Risk factors for mortality were analyzed using Cox proportional hazard models.

RESULTS

In total, 22,024 incident patients were included with 10,006, 5,668, and 6,350 in each group (<65, 65-74, and ≥75 years, respectively). Among the very elderly group, women had a higher cumulative survival rate than men. The survival rate was lower in patients with vascular access via a catheter than in those with an arteriovenous fistula or graft. Very elderly patients with more comorbid diseases had a significantly lower survival rate than those with fewer comorbidities. In the multivariate Cox models, old age, cancer presence, catheter use, low body mass index, low Kt/V, low albumin concentration, and capable status of partial self-care were associated with high risk of mortality.

CONCLUSION

Preparation of an arteriovenous fistula or graft when starting HD should be considered in very elderly patients with fewer comorbid diseases.

The Characteristics of Dialysis Membranes: Benefits of the AN69 Membrane in Hemodialysis Patients

Patients undergoing hemodialysis (HD) experience serious cardiovascular complications, through malnutrition, inflammation, and atherosclerosis. Amputation for peripheral arterial disease (PAD) is more prevalent in patients undergoing HD than in the general population. In addition, revascularization procedures in dialysis patients are often associated with subsequent amputation and high mortality rates. To improve the prognosis of dialysis patients, malnutrition and inflammation must be properly treated, which necessitates a better understanding of the characteristics of dialysis membranes. Herein, the characteristics of several dialysis membranes were studied, with a special reference to the AN69 membrane, noting several similarities to low-density lipoprotein (LDL)-apheresis, which is also applicable for the treatment of PAD. Both systems (LDL-apheresis and AN69) have anti-inflammatory and anti-thrombogenic effects because they use a negatively charged surface for extracorporeal adsorptive filtration from the blood/plasma, and contact phase activation. The concomitant use of both these therapeutic systems may have additive therapeutic benefits in HD patients. Here, we reviewed the characteristics of dialysis membranes and benefits of the AN69 membrane in dialysis patients.

Aortic arch calcification affects causes of death in patients on hemodialysis: a retrospective cohort study

Background

Aortic arch calcification (AAC) is a well-known risk factor for death in patients on hemodialysis (HD); however, the causes of death among them have not been well studied. The study aimed to investigate the distribution of causes of death and long-term prognosis among different degrees of AAC in HD patients.

Methods

A retrospective cohort study was conducted on patients undergoing HD at two clinics in Japan. AAC grades 0 to 3 were categorized by chest radiograph at baseline, and mortality and causes of death were collected. A subgroup analysis was performed to evaluate the relationship between causes of death and age, diabetes mellitus, and dialysis vintage in each AAC grade.

Results

A total of 321 patients were included in the analysis. During 5.2 ± 2.1 years, 117 patients died, and the death rates in AAC grades 0, 1, 2, and 3 were 19.3% (17/88), 35.2% (51/145), 46.3% (25/54), and 70.6% (24/34), respectively. The major causes of death were cardiovascular disease (CVD, 39.3%), infection (20.5%), and malignancy (15.4%) in the entire cohort. In AAC grade 3, CVD mortality (33.3%) remains as the most common cause of death, although death of infection (29.2%) and malnutrition (16.7%) increased markedly. A subgroup analysis showed that AAC grade 3 was mostly old, non-diabetic patients with a long dialysis vintage and was susceptible to death of infection or malnutrition.

Conclusions

CVD was the most common cause of death among all AAC grades, although death of infection and malnutrition markedly increased in those with severe AAC. Attention should be paid to CVD, infection, and malnutrition in HD patients with severe AAC.

Systolic finger pressures during an Allen test before hemodialysis access construction predict severe postoperative hand ischemia

OBJECTIVE

The Allen Test is a simple bedside method for determining hand perfusion. Earlier studies in hemodialysis (HD) patients found that an Allen Test before access construction did not predict hand ischemia later on. The study aimed to assess whether an Allen test combined with finger plethysmography before access surgery has a potential to predict the onset of severe hemodialysis access induced distal ischemia (HAIDI).

METHODS

Prior to the first access construction in chronic kidney disease (CKD) patients, systolic finger pressures (Pdig, mmHg) were obtained using plethysmography at rest and following serial compression of the radial and ulnar artery. A drop in Pdig (∂Pdig) was calculated as the difference between Pdig-rest and Pdig-compression. Severity of postoperative HAIDI was graded as suggested by a 2016 consensus meeting. Patients with a severe type of HAIDI (grade 2b-4, intolerable pain, invasive treatment required) were compared with controls not having HAIDI.

RESULTS

A total of 105 CKD patients (age 70 ±13, 65% males) receiving their first access between January 2009 and December 2018 in one center fulfilled study criteria. Ten patients (10%) developed severe HAIDI 14 ±5 months after access construction. Prior to access creation, all HAIDI patients demonstrated a radial or ulnar dominant hand perfusion pattern compared to just 57% in controls (p=.010). Compression resulted in an almost two-fold greater ∂Pdig in patients with severe HAIDI (51 ±8 mm Hg vs. 27 ±3 mm Hg, p=.005). A 40 mm Hg ∂Pdig cut-off value demonstrated optimal tests characteristics, (sensitivity 80%, specificity 77%, PPV 27%, NPV 97%) indicating a 10 times greater risk of developing severe HAIDI.

CONCLUSIONS

Finger plethysmography quantifying ∂Pdig during an Allen test prior to access creation may identify patients who have a substantially increased risk of developing severe hand ischemia following hemodialysis access surgery.

Is the Rise in the Prevalence of Renal Replacement Therapy at Older Ages the Price for Living Longer?

Background

Renal replacement therapy (RRT) is one of the most expensive in renal medicine. Cross-sectional studies suggest that life expectancy increases in the general population are associated with a higher burden of RRT. This study tests this hypothesis in a prospective setting among people aged 75+ living in Western Europe.

Methods

We gathered sex-specific data for 11 Western European countries in 2005-2014. RRT prevalence on country level was extracted from the ERA-EDTA registry, while data on population size and life expectancy for the 75+ age group came from the Eurostat database. GDP per capita was extracted from the OECD database. To measure the association between RRT prevalence and life expectancy, we performed Poisson regression models separately for each country and for all countries combined. To adjust for confounding, GDP per capita as well as time and country-fixed effects were included.

Results

Our analysis revealed that living longer coincides with rising RRT prevalence at ages 75+ in Western Europe between 2005 and 2014. On average, a 1-year increase in life expectancy was associated with a roughly 20% increase in RRT prevalence [(95% CI) 21-23% in men and 19-22% in women]. However, after adjustments for confounding were made, the association became insignificant among women and became weaker among men, falling to a level of 11% [(95% CI) 6-17%].

Conclusion

Living longer was not necessarily associated with a higher burden of RRT in Western European countries.