Erythropoietin and cardiocirculatory condition in aged patients with chronic renal failure

Exercise Capacity in Pediatric Patients with End-Stage Renal Disease

Objective

To evaluate the correlation between exercise capacity and hemoglobin in pediatric patients with end-stage renal disease (ESRD) treated with automated peritoneal dialysis (APD) and hemodialysis.

Design

Prospective case-control study and retrospective review.

Setting

Dialysis summer camp and Children's Mercy Hospital exercise laboratory.

Participants

Prospective evaluation conducted with 14 patients (9 males, mean age 14.5 ± 2.5 years) who received either home APD (5 patients) or in-center hemodialysis (9 patients), and 8 healthy age-matched controls. Retrospective data derived from 10 children (7 males, mean age 12.3 ± 3.3 years), all of whom received APD.

Intervention

Maximal treadmill evaluation conducted with each patient and control. The hemoglobin value of each patient was also assessed.

Main Outcome Measures

Comparison of the following data generated during treadmill protocol: peak heart rate, blood pressure, oxygen saturation, treadmill time, oxygen consumption (VO2), ventilation (Ve), oxygen consumption at anaerobic threshold (VO2 AT), and respiratory exchange ratio.

Results

The hemoglobin value of the current patient group (12.8 ± 1.6 g/dL) was significantly greater than the previously studied patients (10.5 ± 1.1 g/dL) ( p = 0.001). Treadmill time, VO2, and VO2 AT were significantly lower in both groups of dialysis patients compared to the control subjects ( p < 0.05). No differences were noted in any of these variables when comparing these two groups of dialysis patients only.

Conclusion

The exercise capacity of pediatric dialysis patients is significantly poorer than that of healthy children, an outcome apparently related to factors other than normalization of the hemoglobin value.

Clinical practices and outcomes in elderly hemodialysis patients: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND AND OBJECTIVES

Demand for hemodialysis among elderly patients is increasing worldwide. Although clinical care of this high-risk group is complex and challenging, no guidelines exist to inform hemodialysis practices. The Dialysis Outcomes and Practice Patterns Study (DOPPS) provides a unique opportunity to assess dialysis practices and associated outcomes among elderly versus younger patients on chronic in-center hemodialysis in 12 countries.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Clinical characteristics, dialysis practices, and outcomes of elderly versus younger patients were compared among participants in four DOPPS regions in 2005 through 2007.

RESULTS

Although participant mean age increased over time in all DOPPS countries, the percentage of elderly varied widely. Overall, comorbidities and malnutrition were more common in the elderly. Fistulae were used less frequently among elderly versus younger patients in Europe and North America but not in Australia, New Zealand, and Japan. No difference in treatment time was observed between elderly and younger patients after normalizing for body weight. In all regions, ultrafiltration rates were lower among elderly patients. Elderly patients reported poorer quality of life with respect to the physical but not mental component scores. Mortality risk was three- to sixfold higher in the elderly group, whereas causes of death overall were similar for elderly and younger patients.

CONCLUSIONS

Elderly patients represent a different proportion of DOPPS participants across countries, possibly reflecting differences in policies and clinical practices. In general, hemodialysis practices in the elderly reflected each region's clinical patterns, with some variation by age group depending upon the practice.

Anemia of chronic disease in chronic obstructive pulmonary disease: a case-control study of cardiopulmonary exercise responses

BACKGROUND

Anemia may be present in patients with chronic obstructive pulmonary disease (COPD) and further impair their functional capacity.

OBJECTIVES

This study investigated the prevalence of anemia of chronic disease (ACD) in COPD patients and its impact on dyspnea and exercise capacity, utilizing cardiopulmonary exercise testing (CPET).

METHODS

ACD prevalence was assessed in 283 consecutive patients with stable COPD (263 males, 60 females; age 60.31 ± 5.34 years; percent forced expiratory volume in 1 s 46.94 ± 6.12). ACD diagnosis was based on a combination of clinical and laboratory parameters [hemoglobin (Hb) <13 g/dl for males, <12 g/dl for females; ferritin >30 ng/ml; total iron-binding capacity <250 μg/dl, and transferrin saturation rate between 15 and 50%]. Twenty-seven patients who were identified with ACD (cases) and 27 matched nonanemic patients (controls) completed maximal CPET, and data were compared between the groups.

RESULTS

ACD was diagnosed in 29 patients, which represents a prevalence of 10.24%; the severity of anemia was generally mild (mean Hb: 12.19 ± 0.66 g/dl). Patients with ACD had a higher Medical Research Council dyspnea score compared to controls (2.78 ± 0.44 vs. 2.07 ± 0.55; p <0.001) and lower peak O(2) uptake (VO(2)) (59.54 ± 17.17 vs. 71.26 ± 11.85% predicted; p <0.05), peak work rate (54.94 ± 21.42 vs. 68.72 ± 20.81% predicted; p <0.05) and peak VO(2)/heart rate (69.07 ± 17.26 vs. 82.04 ± 18.22% predicted; p <0.05). There was also a trend for a lower anaerobic threshold (48.48 ± 15.16 vs. 55.42 ± 9.99% predicted; p = 0.062). No exercise parameter indicative of respiratory limitation differed between the groups.

CONCLUSIONS

ACD occurs in approximately 10% of stable COPD patients and has a negative impact on dyspnea and circulatory efficiency during exercise.

Kidney in old age

Epidemiological studies have shown that chronic kidney disease (CKD) is a major health problem especially in an older population. Given the growing segment of the elderly population and the important implication of renal disease on health care, this review discusses the structural and functional changes of the ageing kidney and the underlying mechanisms of age-dependent injury. The implications of these changes in daily clinical practice and the management of CKD is also briefly overviewed.

Voluntary Exercise during Chronic Renal Failure in Rats

PURPOSE

Chronic renal failure (CRF) patients often experience a significant degradation in quality of life that is associated with decreased physical fitness. Previous animal studies have used forced running or swimming as modalities to investigate the interactions between exercise and CRF. These modalities generally include stress responses unrelated to the exercise itself. The purpose of the current work was to determine whether, and to what extent, rats experiencing the onset of CRF would participate in voluntary wheel running exercise. An additional objective was to examine physiological parameters related to skeletal muscle and cardiovascular adaptation in the context of CRF and exercise.

METHODS

Groups of rats were assigned to sham-operated or 5/6 nephrectomy groups, and further divided into running or nonrunning subgroups. Blood, heart, and muscle tissues were collected 30 d after the exercise groups were returned to running wheel-equipped cages.

RESULTS

The results demonstrated that rats experiencing the early stages of CRF will voluntarily exercise to the same extent as sham-operated animals (e.g., sham, 7.2+/-0.8 vs CRF, 6.8+/-0.7 km.d). CRF resulted in increased systolic blood pressure that was not normalized by exercise. CRF induced a decrease in hemoglobin concentration that was prevented by exercise. Voluntary running resulted in an apparently nonpathological left ventricular hypertrophy in both the sham-operated and CRF rats. In locomotor skeletal muscles, CRF resulted in a 31% decrease in citrate synthase activity that was completely blunted by voluntary running activity.

CONCLUSION

Rats experiencing the onset of CRF will run voluntarily. This exercise appears to provide some potentially palliative effects on the skeletal muscle and cardiovascular responses to CRF.

Kidney function in older people: pathology, assessment and management

It is commonly not appreciated that kidney failure is predominantly a disease of older people and that the use of renal replacement therapy (RRT) amongst these patients is increasing rapidly. It is still unclear whether the decline in kidney function with increasing age represents pathology or is part of the normal ageing process. Conventional laboratory approaches to the assessment of kidney function in older people are inadequate, but the use of calculated clearance formulae and serum cystatin C can enable the earlier detection of chronic kidney disease (CKD) in this population. This could facilitate treatment aimed at reducing the progression of kidney disease in older people and improved management of its secondary complications.

Anaemia, cardiovascular disease and kidney disease: integrating new knowledge in 2002

PURPOSE OF REVIEW

The present review assesses recent publications, from 2001 until the present, which address the relationship between cardiovascular disease (CVD) and anaemia in patients with chronic kidney disease.

RECENT FINDINGS

Insights from the recently published basic science literature have helped to place findings from clinical studies into a new context, and thereby assist us to understand and further explore the complex relationship between haemoglobin level and survival in chronic kidney disease. The effects of erythropoietin molecules and the presence of receptors in vascular endothelium, myocardium and other tissues are described. Both observational and interventional clinical studies are examined, and limitations in the methodology and statistical analysis of clinical studies are emphasized, but are given context within the body of literature preceding the past year's publications.

SUMMARY

Data suggest that development of CVD in patients with kidney disease is multifactorial. Several factors associated with CVD are also associated with anaemia, thereby making causal arguments for the role of anaemia in CVD and survival difficult. Arguments are made for the importance of prevention of anaemia and of individualizing therapeutic goals for its treatment. Well designed prospective studies with both CVD events and mortality as outcomes, and with enrollment beginning before the start of dialysis, are essential if we are to determine the optimal therapeutic strategies.