Inge Eidemak

Five Months of Physical Exercise in Hemodialysis Patients: Effects on Aerobic Capacity, Physical Function and Self-Rated Health

Background: The number of chronic renal failure patients treated by hemodialysis (HD) is continuously increasing. Most patients have reduced physical capacity and have a high risk of cardiac and vascular diseases. The aim of this study was to determine the effects of 5 months physical exercise of HD patients’ physical capacity, self-rated health and risk factors for cardiovascular disease. Methods: 33 HD patients were included in the study. Inclusion criteria: HD for more than 3 months, age >18 years. Exclusion criteria: Diabetes mellitus, symptomatic cardiovascular disease, musculoskeletal limitations, severe peripheral polyneuropathy, inability to speak Danish or English, dementia or other mental disorders. The patients were randomly assigned to an exercise group (EG, n = 22) or a control group (CG, n = 11). Prior to randomization, baseline testing was performed. The effects were measured by aerobic capacity, ‘2-min stair climbing’, ‘squat test’, self-rated health (SF36), blood pressure and lipids. All tests were carried out by blinded testers. The intervention consisted of 1 h of physical exercise twice a week for 5 months. Results: 20 patients completed the intervention. Attendance was 74% of all sessions. There were no dropouts caused by complications related to the intervention. The EG had a significant increase in aerobic capacity, ‘squat test’ and Physical Function and Physical Component Scale (SF36). No significant changes were observed in any of the parameters in the CG. Conclusion: Physical exercise twice a week for 5 months increases physical function and aerobic capacity in HD patients. An exercise program with only two exercise sessions per week seems easy to implement in clinical practice with high attendance among participants. Further investigation is needed to determine the effects on blood pressure and lipids. There were no medical complications related to the exercise program.

Assessment and clinical aspects of health-related quality of life in dialysis patients and patients with chronic kidney disease

Background/Aims: It is relevant to investigate health-related quality of life (HRQOL) in dialysis and chronic kidney disease (CKD) patients in order to optimise treatment. The aim of this study was to investigate HRQOL in dialysis and CKD patients, to compare results from patients treated with hemodialysis (HD) and peritoneal dialysis (PD) and to investigate the prediction of dialysis quality control parameters (blood hemoglobin, plasma albumin, and Kt/V) and tobacco smoking in disease-specific HRQOL. Methods: Seventy-one HD, 59 PD, and 63 CKD patients participated in the study. Dialysis quality control parameters were measured and the patients completed the questionnaire Kidney Disease Quality Of Life. Results: PD patients rated Dialysis Staff Encouragement and Patient Satisfaction better than HD patients (p≤ 0.05). Dialysis patients scored significant lower than the general population in all generic HRQOL scales (p ≤ 0.01), whereas CKD patients scored lower than the general population in 5 of 8 scales (p ≤ 0.05). The dialysis quality parameters did not predict dialysis patients’ disease specific HRQOL, but tobacco consumption was independently associated with low scores on a number of HRQOL scales. Conclusion: Based on the results, it is suggested to include elements of HRQOL as a supplement to standard quality control parameters. It is also suggested routinely to include information of the beneficial effects of physical activity already in the predialysis program, and to focus on smoking as a very important risk factor.

Self-rated health and employment status in chronic haemodialysis patients.

Objective: Along with survival and other types of clinical outcome, physical, mental and social well‐being are important indicators of the effectiveness of the medical care that haemodialysis (HD) patients receive. The present cross‐sectional study was designed to assess self‐rated health in HD patients from a large Danish HD centre compared to a Danish general population sample with similar sex and age distributions. Furthermore, employment status and associations between self‐rated health and clinical, social and demographic factors were investigated. Material and Methods: A total of 150 patients were included. They were asked to complete the Short Form 36 (SF‐36) questionnaire and additional questions concerning education and employment status. The SF‐36 consists of eight scales representing physical, social, mental and general health. Clinical, biochemical and dialysis adequacy data were obtained from hospital records. Results: A total of 112 patients completed the questionnaire, giving a response rate of 75%. Compared to the general population sample, HD patients scored significantly lower on all eight SF‐36 scales (p < 0.01), with the greatest difference being observed for items concerning physical functioning. No correlation was found between any of the eight scales and estimates of dialysis adequacy. Of patients aged 18–60 years, 22% were in employment. Conclusion: In a large group of Danish HD patients, self‐rated health (and especially physical function) was found to be substantially impaired compared to the general population and only a small proportion of patients were employed. We believe that results obtained using the SF‐36 questionnaire represent an independent marker of health status in HD patients and should be considered, together with common clinical outcome measures, when monitoring patients. Furthermore, we believe that self‐rated health questionnaires are a useful tool for evaluating the need for and the effects of physical activity programmes in a dialysis unit.

Myosin heavy-chain isoform distribution, fibre-type composition and fibre size in skeletal muscle of patients on haemodialysis

Objective. Chronic uraemia is associated with abnormalities in skeletal muscles, which can affect their working capacity. It is also well known that the fibre-type composition of skeletal muscles influences endurance, muscle strength and power. In this study we therefore determined the size and distribution of muscle fibres and the myosin heavy-chain (MHC) isoform composition in patients on haemodialysis (HD) in order to establish any differences with values for untrained control subjects. Material and methods. Muscle biopsies were obtained from the vastus lateralis muscle of 14 non-diabetic patients on HD. The size and distribution of muscle fibres were evaluated using adenosine triphosphate synthase (ATPase) histochemistry, whilst MHC isoform composition was determined in muscle homogenates using sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Values were compared to those for a group of age-, gender- and BMI-matched untrained control subjects. The aerobic work capacity of the patients was also determined. Results. The MHC composition for I, IIA and IIX isoforms was found to be 35.3%±18.2%, 35.9%±7.1% and 28.9%±15.6%, respectively, findings supported by the ATPase histochemically determined fibre-type composition of the vastus lateralis muscle. The mean fibre area of type 1 and 2 fibres was 3283±873 and 3594±1483 µm2, respectively. The MHC composition and the size of the type 1 fibres of the patients on HD were significantly different from those of the control subjects. Conclusions. The data demonstrate relatively fewer type 1 and consequently more type 2x fibres, with a corresponding change in MHC isoforms (MHC I and MHC IIX) in the skeletal muscle of patients on HD. Several patients on HD were found to have <15% type 1 (or relative percentage of MHC I) fibres. Such a low percentage of type 1 fibres is very rarely observed in normal untrained subjects. Chronic uraemia more severely affects the composition than the size of fibres.

Reliability testing of the Danish version of the Kidney Disease Quality of Life Short Form

Objective. The questionnaire Kidney Disease Quality of Life Short Form version 1.3 (KDQOL-SF™) is valuable for assessing the health-related quality of life in patients treated with chronic dialysis. The aim of this study was to translate and test the reliability of the KDQOL-SF for use in Denmark. Material and methods. Translation into Danish and back-translation into English were performed. Pilot, field and internal consistency reliability tests were performed. Results. Cronbachs α coefficients for the internal reliability test ranged from 0.77 to 0.93 for the eight generic scales. In a test involving all patients, two of the disease-specific scales had Cronbachs α coefficients of <0.70 (“social support” = 0.67; and “quality of social interaction” = 0.43). After removing one item from the scale “quality of social interaction”, Cronbachs α reached 0.63. A test of the scores of peritoneal dialysis (PD) patients discovered low reliability for three disease-specific scales. The KDQOL-SF manual and the Danish manual for the Short Form 36 (SF36) differed in the scoring of four generic scales: “role limitation—physical”, “bodily pain”, “general health” and “social function”. Conclusions. With the exception of the scale “quality of social interaction” the Danish translation of the KDQOL-SF achieved values in the internal consistency reliability test of the same level as the original U.S. version. When data were stratified according to dialysis treatment, the reliability of PD patients scores was lower. Generic data from the questionnaire SF36 should be scored according to the Danish SF36 manual.

Vitamin D, Surface Electromyography and Physical Function in Uraemic Patients

Background: Muscle function is impaired in uraemic patients and several causes have been proposed. Deficiency of 25-hydroxyvitamin D (25-OHD), which affects muscle function in non-uraemic patients, may very well also be associated with the myopathy found in these patients. The aim of this study was to investigate the association between 25-OHD and muscle function as well as physical function in chronic kidney disease (CKD) and peritoneal dialysis (PD) patients. Methods: In this cross-sectional study, 21 adult patients with CKD stage 3–5 and 21 patients treated with PD were included. Standard biochemistry parameters were measured including 25-OHD, 1,25-dihydroxycholecalciferol (1,25-OHD) and parathyroid hormone analysis. Muscle function was determined by 30-second surface electromyography (sEMG) recordings of a right thigh muscle (vastus lateralis) and a second left finger muscle (second dorsal interosseous) under voluntary contractions. Physical function was determined using a 30-second Chair Stand Test and the Short Form 36 quality of life questionnaire. Clinical characteristics were collected from the patient records. Results: Moderate vitamin 25-OHD deficiency (<40 nmol/l) was measured in 52% of patients with CKD and in 71% of the patients on PD. Severe deficiency (<15 nmol/l) was measured in 14% of patients on PD. There were no significant differences between the CKD and PD patients in terms of sEMG results. 25-OHD was not correlated to any results from the tests of sEMG or physical function. However, a higher sEMG frequency and signal root mean square (RMS) were positively associated with a higher Chair Stand Test score. Time to maximum sEMG frequency was negatively correlated to the Chair Stand Test score (p < 0.05), and positively correlated to the level of comorbidity (p < 0.05). sEMG signal peak-peak amplitude, frequency and RMS were positively correlated to the quality of life scales Physical Function, Role Physical, General Health, Vitality, Social Function, Mental Health, and Physical Component Scale (p < 0.001). Conclusions: 25-OHD deficiency was prevalent in uraemic patients in the present study. Muscle function as determined using sEMG and the Chair Stand Test was not associated with 25-OHD. The results may be biased by the limited variation in 25-OHD and masked by effects of several other variables in this very sick population.

The Effects of High-Load Strength Training With Protein- or Nonprotein-Containing Nutritional Supplementation in Patients Undergoing Dialysis

OBJECTIVE The aim of this study was to investigate the effects of high-load strength training and protein intake in patients undergoing dialysis with a focus on muscle strength, physical performance, and muscle morphology. DESIGN This was a randomized controlled study conducted in three dialysis centers. SUBJECTS Subjects for the study included 29 patients undergoing dialysis. INTERVENTION The participants went through a control period of 16 weeks before completing 16 weeks of strength training. Before the training period, the participants were randomly assigned to receive a protein or a nonprotein drink after every training session. MAIN OUTCOME MEASURE Muscle strength and power were tested using the good strength equipment and the leg extensor power rig. Physical performance and function were assessed using a chair stand test and the Short Form 36 questionnaire. Muscle fiber type size and composition were analyzed in biopsies obtained from the m. vastus lateralis. RESULTS All variables remained unchanged during the control period. After training, muscle strength and power, physical performance, and physical function increased significantly. Muscle fiber composition was changed by a relative decrease in type 2x muscle fiber number whereas muscle size at the fiber level was unchanged. There were no effects of combining the training with protein intake. CONCLUSIONS High-load strength training is associated with improvements in muscle strength and power, physical performance, and quality of life. The effects were surprisingly not associated with muscle hypertrophy, and the results did not reveal any additional benefit of combining the training with protein intake. The positive results in muscle strength and physical performance have clinically relevant implications in the treatment of patients undergoing dialysis.

Improved Glucose Tolerance after High-Load Strength Training in Patients Undergoing Dialysis

Background/Aims: The aim of this controlled study was to investigate the effect of high-load strength training on glucose tolerance in patients undergoing dialysis. Methods: 23 patients treated by dialysis underwent a 16-week control period followed by 16 weeks of strength training three times a week. Muscle fiber size, composition and capillary density were analyzed in biopsies obtained in the vastus lateralis muscle. Glucose tolerance and the insulin response were measured by a 2-hour oral glucose tolerance test. Results: All outcome measures remained unchanged during the control period. After strength training the relative area of type 2X fibers was decreased. Muscle fiber size and capillary density remained unchanged. After the strength training, insulin concentrations were significantly lower in patients with impaired glucose tolerance or type 2 diabetes (n = 14) (fasting insulin from 68 ± 12 (46-96) to 54 ± 10 (37-77) pmol/l, p < 0.05, 2-hour insulin from 533 ± 104 (356-776) to 344 ± 68 (226-510) pmol/l, p < 0.05, total insulin area under the curve from 1,868 ± 334 (1,268-2,536) to 1,465 ± 222 (1,094-1,913), p < 0.05). Insulin concentrations were unchanged in patients with normal glucose tolerance (n = 9). Conclusion: The conducted strength training was associated with a significant improvement in glucose tolerance in patients with impaired glucose tolerance or type 2 diabetes undergoing dialysis. The effect was apparently not associated with muscle hypertrophy, whereas the muscle fiber type composition was changed.

Fiber type-specific response of skeletal muscle satellite cells to high-intensity resistance training in dialysis patients

Introduction: The aim of this study was to assess the effect of high‐intensity resistance training on satellite cell (SC) and myonuclear number in the muscle of patients undergoing dialysis. Methods: Patients (n = 21) underwent a 16‐week control period, followed by 16 weeks of resistance training 3 times weekly. SC and myonuclear number were determined by immunohistochemistry of vastus lateralis muscle biopsy cross‐sections. Knee extension torque was tested in a dynamometer. Results: During training, SCs/type I fibers increased by 15%, whereas SCs/type II fibers remained unchanged. Myonuclear content of type II, but not type I, fibers increased with training. Before the control period, the SC content of type II fibers was lower than that of type I fibers, whereas contents were comparable when normalized to fiber area. Torque increased after training. Conclusions: Increased myonuclear content of type II muscle fibers of dialysis patients who perform resistance training suggests that SC dysfunction is not the limiting factor for muscle growth. Muscle Nerve 52: 736–745, 2015

Increased rate of force development and neuromuscular activity after high‐load resistance training in patients undergoing dialysis

The aim of this study was to investigate the effects of high‐load resistance training on the rate of force development and neuromuscular function in patients undergoing dialysis.