Assessment of Health-Related Fitness in the Patients with End-Stage Renal Disease on Hemodialysis: Using Eurofit Test Battery

Abstract

The main objectives of this study were to evaluate the health-related physical fitness for the patients with end-stage renal disease on hemodialysis and determine the suitability of Eurofit Test Battery for adults to decide their health-related physical fitness level. Eighteen patients with end-stage renal disease (ESRD) on hemodialysis (age 49.7+17.9, 10 female / 8 male) was evaluated and compared with 22 age-matched healthy subjects (age 50.5 + 9.4 years, 13 female / 9 male) for this purposes. Eurofit Test Battery for Adults is composed of aerobic fitness, musculoskeletal fitness, motor fitness, and anthropometry components. Aerobic fitness, which was assessed by six minutes walking distance, was lower in the patient group than controls (p < 0.05). Hemodialysis patients had lower motor fitness (0.000) and musculoskeletal fitness including vertical jump and handgrip tests (0.047, 0.002). Percentage of body fat and skinfold thickness values measured from triceps, subscapular, abdominal, and thigh were also lower in patient group (p < 0.05). Additionally no complication was seen during and/or after the tests. In conclusion, the Eurofit for adults may be considered a useful test battery to evaluate the physical fitness and design the health-related physical fitness program based on the Eurofit results in this population.

Keywords:

• health-related fitness
• hemodialysis
• Eurofit

INTRODUCTION

End-stage renal disease (ESRD), the deterioration of nephrons to an advanced stage resulting in the dysfunction of the kidneys for a long period, requires either dialysis treatment or transplantation in advance.[1] ESRD results in a negative clinical status, which in turn results in both structural and functional changes in the musculoskeletal system.[2] Consequently, the patient is faced with a sedentary life, making the patient even further dependent.[3]

Dialysis regulates the patients' general condition and fluid-electrolytes balance, assures the disposal of accumulated toxic substances in the body, facilitates the patients' continued healthy life, and prepares the patient for the transplantation.[4] During this stage of treatment, there are two considerations: to increase both the quality of life and the life expectancy.[5] To improve and enhance the quality of life through dialysis or transplantation, a well-planned exercise program also must be included.[6],[7] As the exercise program entails a risk in itself, the implemented program must be carefully planned, coordinated, and supervised based on health-related fitness in this population.[8] There are many exercise training studies in patients with end-stage renal disease on hemodialysis, but few, if any, health-related fitness assessment in the literature. For this reason, we hypothesize the suitability of Eurofit for adults in this group of patients and sought to evaluate the hemodialysis patients relevant to health-related physical fitness using the Eurofit Test Battery, which tests all approved, valid, and reliable measures of these components for adults.[9],[10]

PATIENTS AND METHODS

From the 25 end-stage renal disease patients in the maintenance hemodialysis program at the Renal Unit of Izmir Aegean University Hospital, 18 without any exclusion criteria (see Table 1) and 22 aged-matched healthy subjects volunteered to participate in the study. The hemodialysis patients had all been undergoing regular HD, three sessions a week, four hours each session.

Table 1 Contraindications for including patients in the study

1. Pre-dialysis potassium > 5.5 mmol 1

2. Hb < 10 g/dL

3. Unstable hypertension

4. Congestive heart failure (grade > II according to NYHA)

5. Cardiac arrhythmias (≥ III according to Lown)

6. Recent myocardial infarction or unstable angina

7. Persistent hyperkalemia before dialysis

8. Peripheral vascular disease

9. Arthritic or orthopaedic problems limiting functional capacity

The study had local research and ethics committee approval, and all subjects gave written consent. All assessments of HD patients was conducted one hour and one half-hour immediately prior to hemodialysis using Eurofit Test Battery for Adults based on aerobic fitness, musculoskeletal fitness, and motor fitness and anthropometry components.[9],[10]

Aerobic Fitness

A six-minute walking test (6MWT) was used in the determination of aerobic fitness in place of 2 km walking test, ergometer test, or multistage shuttle run test in original Eurofit Battery. Because the 6MWT is more suitable for chronic patient groups, aerobic fitness was tested within this protocol according to American Thoracic Society (ATS) 6MWT statement.[11] Blood pressure (systolic/diastolic blood pressures (SBP/DBP) and heart rate (HR) were measured before and after the test. The perception of exercise intensity was assessed by Original Borg Scale.[12] At the end of the test, the distance walked was recorded. The following formula was used to determine VO_2max (ml.min.⁻¹kg⁻¹):where RPP is the rate-pressure product (HR × SBP).

Musculosceletal Fitness

The musculoskeletal fitness of the patients was assessed by the components of muscle strength and endurance and flexibility of Eurofit Test Battery for Adults.

The grip strength for the hand muscle strength was performed with JAMAR dynamometer, once with each elbow in flexion, once with each elbow in extension. Each measurement was repeated twice and the higher score was recorded.

The vertical jump test was used in order to measure the lower extremity muscle strength. The subject jumped as high as possible at a 20 cm distance from the wall and the distance he/she jumped was measured.

Side-bending test was used for evaluating the spinal flexibility. The patients stood upright against a wall on two parallel lines at right angles to the wall and 15 cm apart. The patients held their arms straight against the sides of their body. The position of the middle finger on each side was marked with a horizontal line on the lateral thigh. The subject was then asked to bend sideways as far as possible while maintaining contact between the back and the wall. The distance between the first and last position of the middle finger was recorded.[13]

Motor Fitness

In the assessment of motor fitness, the single leg balance test was used with eyes open and closed. At the end of the test total time was recorded.

Anthropometry (Body Composition)

In order to assess body composition, height, body weight, body mass index, skinfold thickness, and percentage of body fat (PBF) were measured. Body mass index (BMI) was calculated as body weight in kg divided by the square of height in meters (Kg / m²).

The skin fold thickness measurements were carried out in Holtain Calipers with 0.2 mm spaces, and the measurements have been applied on the right side of the body. Measurement sites were the biceps, triceps, subscapular, suprailiac, abdominal, and thigh. Four sites (biceps, triceps, subscapular, suprailiac) are measured to calculate the percentage of body fat.

Statistical Analysis

Mann-Whitney U Test was used to determine the significance of the outcome measurements between the two groups. The level of statistical significances was set at p < 0.05.

RESULTS

Subject characteristics have been given in Table 2.

Table 2 Subjects characteristics

	HD group (n = 18)	Control group (n = 22)
Age (years)	49.7 ± 17.9	50.5 ± 9.3^*
Sex (F:M)	10: 8	13:9^*
Weight (kg)	62.2 ± 15.6	68.4 ± 9.6^*
Height (cm)	160.9 ± 10.8	161.8 ± 7.0^*
Months on hemodialysis	103.06 ± 55.96

Values are mean ± SD. Abbreviations: HD = hemodialysis group, F = female, M = male.

^*not significant.

BMI was similar in the two groups, whereas PBF was significantly lower in HD subjects (27.8 ± 10.2 %, 34.5 ± 6.8 %, p < 0.05). Skinfold thickness of the triceps, subscapular, abdominal, and thigh regions were significantly lower in HD patients (see Table 3).

Table 3 Comparison of the body compositions

	HD group (n = 18)	Control group (n = 22)	Mann-Whitney U Test
BMI (kg/m^2)	23.8 ± 5.1	26.04 ± 3.5 0.13
PBF (%)	27.8 ± 10.2	34.5 ± 6.75	0.04^*
Skin fold thickness (mm)
Triceps	16.5 ± 9.2	22.5 ± 7.5	0.02^*
Biceps	10.9 ± 5.6	14.3 ± 7.7	0.16
Subscapular	15.6 ± 8.4	24.1 ± 6.5	0.001^*
Abdominal	22.3 ± 10.1	30.4 ± 6.3	0.01^*
Suprailiac	12.0 ± 6.6	17.8 ± 5.5	0.07
Thigh	21.8 ± 10.0	24.3 ± 7.2	0.01^*

Values are mean ± SD. Abbreviations: HD = hemodialysis group, BMI = body mass index, PBF = percentage of body fat.

^*p < 0.05.

The results of the 6MWT are given in Table 4. Walking distance, VO_2max, and score of Borg Scale were lower in HD patients. In addition, it was seen that HD patients showed lower HR responses than the controls.

Table 4 Comparison of cardiopulmonary fitness values

	HD group (n = 18)	Control group (n = 22)	Mann-Whitney U Test
Distance (m)	445.2 ± 116.6	538.9 ± 73.6	0.008^*
HR (beats min^−1)	82.8 ± 8.3	88.9 ± 22.4	0.02^*
SBP (mmHg)	139.4 ± 28.9	132.5 ± 16.2	0.41
DBP (mmHg)	75.5 ± 8.6	81.4 ± 10.9	0.07
VO2 max (ml.kg^−1.dk^−1)	12.0 ± 5.7	15.7 ± 3.1	0.34
Original Borg Scale	13.1 ± 2.4	9.2 ± 2.2	0.04^*

Values are mean ± SD. Abbreviations: HD = hemodialysis group, HR = heart rate, SBP = systolic blood pressure, DBP = diastolic blood pressure, VO_{2 max} = maximal oxygen uptake.

^*p < 0.05.

In the evaluation of musculoskeletal fitness, vertical jump and grip strength tests were significantly lower in the HD group compared with the controls (p < 0 .05; see Tables 5 and 6).

Table 5 Comparison of motor and musculoskeletal fitness values

	HD group (n = 18)	Control group (n = 22)	Mann-Whitney U Test
Time standing with eyes opened (second)	19.0 ± 17.2	54.3 ± 10.7	0.000^*
Time standing with eyes closed (second)	6.1 ± 7.1	21.5 ± 958	0.000^*
Vertical jump test (cm)	210.7 ± 19.8	220.9 ± 14.0	0.047^*
Hand grip
Elbow flexion (kg)	22.7 ± 8.6	33.2 ± 8.4	0.002^*
Elbow extension (kg)	24.4 ± 10.2	34.5 ± 8.8	0.002^*
(R) Side-bending test (cm)	46.8 ± 6.2	43.0 ± 3.5	0.06
(L) Side-bending test (cm)	46.9 ± 6.2	43.2 ± 3.7	0.09

Values are mean ± SD. Abbreviations: HD = hemodialysis group, R = right, L = left.

^*p < 0.05.

Table 6 Comparison of hand grip test results between arm with fistula and without fistula in HD group

	HD (n = 18)
	With fistula	Without fistula	p value
Elbow flexion (kg)	18.3 ± 9.1	22.8 ± 8.6	0.00^*
Elbow extension (kg)	19.7 ± 8.9	24.4 ± 10.1	0.00^*

Values are mean ± SD. Abbreviation: HD = hemodialysis group.

^*p < 0.05.

Flexibility values were not different for both the left and right sides (p > 0.05). In the balance test with eyes open and closed for motor fitness, standing time was extremely shorter in HD patients in both situations (p < 0.05; see Table 5). There were no complications with the patients during and/or after tests under the nephrologists' and physiotherapists' observation.

DISCUSSION

Today ESRD is a still major health concern. Complications such as uremia, anemia, myopathy, and neuropathy decrease muscular strength, cardio-pulmonary fitness, and quality of life,[14],[15] which is why this population is seen more frequently in physiotherapy practice currently.

On the other hand, the Eurofit Test Battery was not employed in this group previously, and its novelty itself assured total originality in the process.

Johansen et al.[16] sought to comprehend whether hemodialysis patients differ from healthy sedentary persons. To ascertain whether or not they were as active, they researched physical activity levels and clinical status. It was determined that hemodialysis patients were less active than healthy sedentary persons. The difference between the two increased in parallel to age. It was indicated that anemia and muscular weakness were key factors in diminishing functional capacity.

Studies on patients with myopathic changes showed oxygen deficiency in the muscles and decrease in VO_2max. Myopathy related to uremia inflictions and lessening of oxidative enzyme activities cause fibrillary atrophy and capillary density loss in muscles.[17],[18]

Body composition in view of muscle pathophysiology was also researched. Chen et al.[19] evaluated body compositions in two groups (normal and control) consisting of 40 people at similar ages. There was no statistical difference between the groups of age, sex, height, weight, lean body mass, or fat composition.

Williams et al.[20] also had a research group composed of 180 hemodialysis cases in which skinfold measurements were taken from both m.biceps brachii and m.tricep brachii according to sex. Related nutritional status was also questioned. In men, muscular mass was found to be 50%; in women, body fat was significantly decreased. These conclusions were attributed to insufficient nutritional habits as it stated in the literature.[21] In our research, skinfold thickness were measured from seven regions; we encountered no differences in body fatness and lean body mass. Due to small sample sizes and because we did not distinguish between sexes, we did not evaluate nutritional status; however we are convinced that these two points should be questioned in further research.

A test of aerobic fitness is available using the six minute walking test on COPD, heart disease, and DM cases (i.e., those inflicted with functional loss of capacity). It also uses walking, the most natural physical activity of all.[9]

Enright et al.[22] researched a group of 117 healthy males and 173 healthy females varying in age from 40–80. Walking performance was evaluated, and we obtained values as a reference norm for 6MWT. In this study, in healthy females 494 meters were completed, and 576 meters in males. In our study, we noted that the distance for hemodialysis patients was 445.22 meters; however, in the control group, this distance was 538 meters. The difference between the two groups was statistically significant. This further displays the real loss of functional capacity of the hemodialysis cases. Despite the lesser distance covered by the hemodialysis group in relation to reference values, the application is one that provides both relevant data and reconfirms the method.

Painter et al.[23] researched the effects of anemia on the hemodialysis patients by utilizing hemoglobin, VO_2max, and SF–36 quality of life questionnaires. They then made relative comparisons with normal healthy cases. The conclusion was a lower level of hemoglobin, VO_2max, and SF-36 values. In our research, the distance covered in the six minute walk and aerobic fitness as perceived by VO_2max values was lower. This indicates the length of the disability (i.e., 8 years), which in our case was longer than Painter et al. study group (i.e., 0.5–3.4 years).

As seen in our study, the limited walking distance can be due to cardiopulmonary and musculoskeletal origins. Once again, the cases studied in the 6MWD showed the rate perceived exertion levels to be higher than the control group. This result exemplifies the lower functional capacity of the hemodialysis cases.

We received important data on neuromusculoskeletal losses in terms of motor fitness and musculoskeletal fitness. We evaluated motor fitness by both standing on one leg with eyes open and closed. Here again, the hemodialysis cases period of balance in both forms was shorter than that of the control group. According to collected data being below Eurofit standards, we concluded that aging is a factor in loss of balance.

In hemodialysis cases, the two primary causes of balance difficulties are myopathia and hypotension. This hypothesis is strengthening by the fact that 55.5 of our patients suffered from hypotension.

We evaluated musculoskeletal fitness by using vertical jump for lower extremity extensor strength. Hand grip was used for upper extremity strength determination. Once again, the result of both tests on hemodialysis cases was lower than the figures on the control group.

In the literature, grip strength studies are related mostly dominant or non-dominant hand strength in the healthy population.[24] For our research, the arm without fistula was considered dominant. In our study, we also measured the non-dominant arms at elbow flexion and extension. The results in elbow flexion were lower than those of extension. Though we didn't encounter a statistical difference, this result indicated that force distribution occurred from powerful muscles to weaken muscles. The arm with fistula was checked also against the values of the arm without fistula, and all cases were dramatically lower. This may be evidence of the nonuse of the arm with fistula in their daily living activities, which have been outlined in the literature.

In our study, we also noted that, though insignificant, flexibility decreases. The immobility during hemodialysis and correspondingly in daily life, the arthritis development through time, and pain resulted in body flexibility diminishing.

CONCLUSION

In conclusion, two results were obtained from this research. First, it was seen that health-related physical fitness in hemodialysis patients resulted in a significant decrease in all aspects. Thus, limited health-related physical fitness should be taken into consideration during daily hemodialysis treatment, and must be improved by regular fitness program. Second, the Eurofit Test Battery may a useful instrument to ascertain the specific aspects related to hemodialysis cases in terms of health-related fitness; a well-planned exercise program that was tailored to hemodialysis patients' needs can be set through the Eurofit Test Battery.

ACKNOWLEDGMENTS

The authors would like to thank to Renal Unit of Aegean University Staff, and particularly Prof. Dr. Fehmi Akçicek, for their scientific cooperation. The authors also thank Mr. C. Francis Noonan for his linguistic support.