Keywords

6.1 Introduction

With increasing rates of population aging and lifestyle diseases, the rate of occurrence of chronic kidney disease (CKD) requiring renal replacement therapy is increasing worldwide [1]. According to a study conducted by the Japanese Society for Dialysis Therapy (JSDT), there were approximately 330,000 patients, with an average age of 67.9 years, receiving dialysis in Japan at the end of 2016, and 70% of these patients were over 65 years of age [2]. Japan’s proportion of 65 years-and-over dialysis patients is nearly double that of the US and Europe, and it has been pointed out that the rate of annual increase of this segment of the population has also been extremely high over the past 20 years [3]. In this way, population aging is a striking feature in terms of the epidemiological background of Japan’s hemodialysis patients, and along with aging, more patients are showing physical frailty.

Physical frailty is the state of heightened vulnerability to external stresses, due to the weakening of various physical residual functions caused by aging [4, 5]. Not only does it make the body unable to maintain physiological systems and life functions in the event of incidents like infections or short-term hospitalizations, but it is also known for causing vulnerability to adverse outcomes including mortality, institutionalization, and falls [6,7,8]. Many factors are related and unified into a cycle of frailty associated with declining energetics and reserve. There is a broad international consensus that markers of frailty include age-associated weight (lean body mass) loss; chronic undernutrition; loss of muscle mass (sarcopenia); and declines in endurance, walking ability (walking speed), and physical activity (Fig. 6.1) [5]. In brief, frailty is independent of the illness conditions and disabilities a patient may have and may determine medical treatment progress after the illness [9]. However, frailty is essentially a reversible condition and may be reversed toward normal by appropriate intervention [9, 10]. Therefore, the diagnosis of physical frailty is of major significance [10].

Fig. 6.1
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Cycle of frailty

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6.2 The Prevalence of Physical Frailty in Hemodialysis Patients

Based on the concept and evaluation standards of physical frailty defined by Fried et al. [5], the author and colleagues evaluated 252 hemodialysis patients (average age 67 years) capable of independent mobility who were visiting hospitals for outpatient care and found that 19.4% of men and 23.3% of women, or roughly one-fifth of the patients, were in a state of frailty (Fig. 6.2). Considering that the frequency of frailty among the elderly aged 65–69 years without kidney disease living in the region is <1.9% [11], the prevalence of frailty among hemodialysis patients is approximately 10 times that among average seniors. Unfortunately, the rate of physical frailty is not the most important point. When McAdams-DeMarco et al. [12] studied the mortality rate of three groups of frail, intermediately frail, and non-frail hemodialysis patients over a period of 3 years, they reported that, although there was a significantly higher rate of mortality among the frail and intermediately frail groups compared to that in the non-frail group, there was no difference in the mortality rates of the frail and intermediately frail groups. This showed that it is not only necessary to pay attention to frail patient groups but to also identify and develop appropriate exercise-based approaches for those in a pre-frail condition [13].

Fig. 6.2
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Prevalence of frailty in ambulatory patients on hemodialysis. The mean age of patients enrolled in the study, who were able to ambulate without any assistance, was 67.4 years

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6.3 Positioning Exercise Therapy for Hemodialysis Patients: Exercise Therapy for Disease Management

There are still no guidelines that have earned an international (broad) consensus regarding exercise therapies and exercise instructions for CKD patients, but the Kidney Disease Outcomes Quality Initiative (K/DOQI) Clinical Practice Guidelines that were published in 2005 have become a foundation for exercise guidance carried out as a part of lifestyle guidance [14]. The K/DOQI first indicated diabetes, hypertension, and dyslipidemia as basic risk factors for cardiovascular disease, noted the importance of appropriately managing anemia and metabolic abnormalities as the characteristic risk factors of kidney failure, and provided information to rectify lifestyle-related risks such as smoking and physical inactivity. Additionally, while it lists guidelines for exercise instructions for dialysis patients and recommends physical activity, it also specifies the consideration of the effects of complications and implementation based on an evaluation of physical functions. With regard to these physical function evaluations in particular, it states that they should be regularly conducted every 6 months, and that they should not only merely assess the level of physical functions, but be implemented as a part of disease management. There were no major developments regarding exercise instruction guidelines in the Kidney Disease Improving Global Outcomes (KDIGO) Clinical Practice Guideline published in 2012 [15], but the guidelines published in 2016 by the European Renal Association and European Dialysis and Transplant Association (ERA-EDTA) included considerations focused on patients aged 65 years and over with CKD severity at Stage 3b (estimated glomerular filtration rate < 45 mL/min/1.73 m3) [16]. These guidelines contain many reviews about evaluation items for physical functions and exercise therapy effects and many points that should be referenced when implementing therapeutic exercise for Japanese dialysis patients, based on the fact that the average age of Japanese dialysis patients is over 65 years.

6.4 Physical Functions and Physical Activity Levels of Hemodialysis Patients

The abovementioned ERA-EDTA (2016) guidelines indicate that regular physical function evaluations should be carried out as a part of disease management [16]. For these evaluations, the guidelines recommend using simple evaluation indicators, that is, “field tests” that can be used in actual clinical settings, rather than test tools that use expensive special equipment. They specifically list the sit-to-stand test as an indicator of leg muscle strength, walking speed, and 6-min walk test [17,18,19,20,21,22,23]. As will be mentioned later, walking speed is a strong indicator that predicts the deterioration of physical functions as well as prognoses.

6.4.1 Status of Physical Functions and Physical Activity Levels

The radar chart in Fig. 6.3 shows the relative values of leg muscle strength (knee extensor strength), walking speed, standing balance (one-leg standing time), flexibility (range of joint motion), and physical activity levels of hemodialysis patients attending the dialysis clinic for outpatient care to which the author and colleagues belong, with the value of 100 being the average value for age- and sex-matched healthy individuals. The average age of the 252 hemodialysis patients participating in this study was 67.2 years, with an average dialysis history of 9.7 years; as such, they are approximately in line with the 2016 study results shown by the JSDT [2]. Therefore, it is thought that these results showed the characteristics of the physical functions and physical activity levels of dialysis patients in Japan. Supposing that the difference was equivalent to the degree of decline when compared to healthy persons, leg muscle strength, walking speed, standing balance, and range of joint motion decreased to approximately 60–70% of those of healthy persons, respectively, and physical activity level was under 50%. Furthermore, physical functions and physical activity levels decreased with age, but longer periods (years) of hemodialysis contributed greatly to the degree of decline in both functions and levels (Fig. 6.4) [24]. The results showed that when the period of dialysis was >15 years, there was a striking negative effect on these indicators.

Fig. 6.3
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Physical functions and physical activity levels in ambulatory patients on hemodialysis. Physical function (muscle strength, walking speed, balance, flexibility) and physical activity level (steps) for ambulatory hemodialysis patients are expressed as a percentage of the mean value for the normal subjects matched by age and sex. The mean age of hemodialysis patients enrolled in the study, who were able to ambulate without any assistance, was 67.2 years

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Fig. 6.4
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Relationship between age, physical function, and physical activity by dialysis vintage. Dialysis vintage, time (years) on hemodialysis; yrs years

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6.4.2 Prognoses with Relation to Physical Functions and Physical Activity Levels

Figures 6.5, 6.6, 6.7, 6.8, 6.9, and 6.10 show the relationship between leg muscle strength, walking speed, and physical activity levels (the number of steps) of hemodialysis patients attending the dialysis clinic for outpatient care to which the author and colleagues belong and their prognoses (mortality rate and cardiovascular events). The average age for each was approximately 67 years; data that reflects the current aging of hemodialysis patients in Japan.

Fig. 6.5
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Histogram of lower extremity muscle strength in male and female hemodialysis patients

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Fig. 6.6
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Lower extremity muscle strength and subsequent mortality in hemodialysis patients. Kaplan–Meier analysis of survival for 202 hemodialysis patients. Participants with knee extensor strength above the median value of 40% at baseline had significantly better survival than those with a lower value (P < 0.003 by log-rank test)

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Fig. 6.7
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Histogram of maximum walking speed in male and female hemodialysis patients

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Fig. 6.8
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Maximum walking speed and subsequent cardio-cerebrovascular events in hemodialysis patients. Kaplan–Meier analysis of incidence rates of cardio-cerebrovascular events according to maximum waking speed quartiles for 188 hemodialysis patients. Participants with maximum walking speed above the value of 89 m/min for men, 85 m/min for women at baseline had a significantly lower cumulative incidence of cardio-cerebrovascular events compared to other patients during the follow-up period (P <0.001 by Log-rank test)

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Fig. 6.9
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Histogram of physical activity (steps) in hemodialysis patients

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Fig. 6.10
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Physical activity (steps) and subsequent mortality in hemodialysis patients. Kaplan–Meier analysis of survival for 282 hemodialysis patients. Patients with physical activity above the 4000 steps per a non-dialysis day at baseline had significantly better survival than those with lower values (P < 0.001 by log-rank test)

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The frequency distribution in Fig. 6.5 shows the results of muscle strength values taken when patients extended their leg at maximum strength in the extension direction from a 90-degree stance in a seated position, measured with a handheld dynamometer. The measurement unit is body weight ratio (%), to adjust the difference in physical constitution among patients [25, 26]. It has been shown in previous reports that a body weight ratio under 40% would not satisfy the muscle strength level necessary to walk without difficulty [27]. The results showed that when comparing dialysis patients with leg strength under this body weight ratio of 40% with others (those with a leg strength body weight ratio of 40% and over), there was a distinctly higher ensuing mortality rate for the former group [28] (Fig. 6.6). Further analysis using a Cox proportional hazards regression model clarified that patients with severely decreased leg strength (<40%) had a 2.7-fold higher risk of death than those with high leg muscle strength [28]. That is, a clear decline in leg muscle strength not only interferes with the activities of daily living (ADL), but it is also an independent risk factor that worsens prognoses.

The distribution in Fig. 6.7 shows the results of measuring the walking speed (maximum walking speed) when patients were asked to walk as quickly as possible, without running, along a 10-m corridor [29]. When reviewing later cardiovascular events by the four quartiles of those walking speed results (Q1–Q4), as shown in Fig. 6.8, it was observed that the group of patients with the slower walking speeds (Q1 and Q2) had distinctly higher rates of cardiovascular events than the other patient groups (Q3 and Q4). That is, patients who had a maximum walking speed above the value of 89 m/min for men and 85 m/min for women at baseline had a significantly lower cumulative incidence of cardio-cerebrovascular events compared to other patients during the follow-up period. Further analysis using a Cox proportional hazards regression model showed that the hazard ratio for clinical events per 10 m/min increase in maximum walking speed was 0.77 [29]. Based on our subsequent analysis, if the lowest values for Q3 walking speed (men: 89 m/min, women: 85 m/min) are exchanged for a comfortable walking speed, they align with those used for diagnostic criteria for frailty (1.0 m/s) or sarcopenia (0.8 m/s) [19, 30,31,32], which shows that walking speed can be an important marker predicting frailty diagnoses and prognoses of hemodialysis patients.

The distribution in Fig. 6.9 shows the results of patients walking steps measured on the 4 days that patients were not receiving dialysis. Surprisingly, the greatest number of patients (mode) were in the group that walked an average of under 1000 steps per day, despite these being non-dialysis days that were not limited by the time constraints of dialysis treatment. Furthermore, when reviewing the relationship between this physical activity level (number of steps) and prognoses, there was a clear and significantly greater ensuing mortality rate for patients with an average of <4000 steps per day on non-dialysis days than those who had a greater average number of steps (Fig. 6.10) [33]. Viewing the relationship between prognoses and changes in physical activity levels over time, it was clear that there was a major difference in ensuing mortality rates when comparing those whose activity levels decreased by 30% and those whose activity levels increased by 30%, relative to each patient’s activity level (number of steps) from 1 year prior [34]. Furthermore, when reviewing the relationship between the increase or decrease in physical activity levels (number of steps) (positive or negative, with the boundary of 0) and mortality risk (hazard ratio), it was shown that mortality risks increased sharply when the number of steps declined (Fig. 6.11) [34]. In this way, because physical activity levels are strongly influenced by physical functions such as leg muscle strength and walking speed, these could be useful disease management indicators that keenly reflect physical conditions and subsequent outcomes [35, 36].

Fig. 6.11
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Change in physical activity (steps) and mortality hazard ratio in hemodialysis patients. The cubic spline survival analyses exhibit the association between change in physical activity and mortality, after adjusted by age, sex, time on hemodialysis, body mass index, primary kidney disease, comorbidity index, serum albumin, and baseline physical activity

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6.5 Activities of Daily Living of Hemodialysis Patients

As with the aforementioned physical activity levels, an accurate grasp of the ADL is important for surmising a target person’s condition, as well as their physical and even mental aspects [19, 20, 37]. If a physical function impairment should occur, such as a bone fracture due to a fall, or a cerebral stroke, a person can quickly change from being independent in their ADL to being dependent in their ADL (Fig. 6.12) Thus, it is easy to grasp the reasons or causal relationships for a decline in ADL [38, 39]. However, for patients with CKD requiring dialysis treatment, it is often difficult to grasp the causal relationship merely based on their having a chronic illness. In particular, ADL limitations have already begun to occur before the initiation of dialysis in CKD patients [40]. For the above acute diseases, the decline in physical activity level or ADL is the result of the occurrence of a physical dysfunction, but for chronic illnesses, it is sometimes the case that a decline in physical activity level or ADL leads to further decline in physical functions. That is, for hemodialysis patients, the decline of physical functions, physical activity level, and ADL may all influence one another and create a vicious cycle that has adverse effects on quality of life (QOL) and prognoses (Fig. 6.13) [26, 41]. Therefore, it is necessary to regularly conduct ADL evaluations in addition to physical functions and physical activity levels previously mentioned in Sect. 6.4 [42].

Fig. 6.12
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ADL dependency and difficulty evaluations. ADL activities of daily living, IADL instrumental ADL

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Fig. 6.13
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A cycle of decline in physical functions, physical activity level, and ADL. ADL activities of daily living

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6.5.1 ADL Dependency Evaluations

Figure 6.14 shows the relationship between mortality risk and ADL dependency scores using 5 basic ADLs and 8 instrumental ADLs, for a total of 13 ADLs (functional status score), with a study target of 7000 dialysis patients from Japan (n = 1700) and overseas [43]. In this large-scale study, scores were determined by assigning 1 point for every ADL that a patient can conduct independently (dependent score: 0), with scores of <8 out of 13 determined to be indicators of a severe level of ADL decline. As shown in Fig. 6.14, patients with a score of <8 have a higher mortality risk than those with higher scores, and this effect increases with age: for patients over 65 years of age, those with scores <8 have nearly three times the mortality risk of those with a perfect score of 13. Therefore, maintaining ADL independence for senior dialysis patients is an extremely important therapeutic strategy for keeping their prognoses from worsening [20].

Fig. 6.14
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Mortality risk (per year) by age and ADL (functional status score). The functional status (FS) score has a total of 13 ADL items consisting of 5 basic ADLs (eating, getting dressed, bathing, using the toilet, transferring from bed to chair) and 8 instrumental ADLs (using the telephone, getting places beyond walking distance, grocery shopping, preparing meals, doing housework or handyman work, doing laundry, taking medications, managing money)

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6.5.2 ADL Difficulty Evaluations

Generally, when evaluating ADLs in clinical setting, each assessment is rated on a two-point scale (independent and dependent) (Fig. 6.12). In the previous section (see Sect. 6.4.1), hemodialysis patients were evaluated in two groups, independent and dependent. However, most of clinically stable patients who receive outpatient dialysis services can perform basic ADL and instrument ADL tasks without assistance [44, 45]. On the other hand, even though these outpatient patients are able to travel and move independently, few are actually able to accomplish these tasks “comfortably” and many have a sense of hardship. Thus, it is often impossible to grasp ADL issues using the above-mentioned two-valued standard (Fig. 6.12). We developed the questionnaire on perceived mobility difficulty using a 5-point scale based on difficulty (1, not possible; 2, severe difficulty; 3, moderate difficulty; 4, mild difficulty; and 5, ease) for hemodialysis patients [45] (Fig. 6.15). This questionnaire comprises 12 items divided into the following three categories, which were obtained by a factor analysis: “basic ADL,” “ambulation,” and “walking up or down stairs. With a target group of 216 hemodialysis patients (average age of 67 years), Fig. 6.16a shows the frequency distribution results on the scale of dependency using the Functional Independence Measure, and Fig. 6.16b shows the result distribution using the difficulty scale we developed, for the same group of patients. As these results show, the results of the dependency evaluation indicated that nearly all subjects had independent mobility, and thus there was a concentration of perfect scores. Meanwhile, when the evaluation scale is based on difficulty, there was a wide variety of scores. Furthermore, Fig. 6.17 shows the distribution (percentage) of scores 1–5 for each of the 12 items [45]. Since the study subjects were patients capable of visiting the clinic, roughly <10% were a score of impossible (dependent). On the other hand, if we consider those who had difficulty (3 or below) even while being capable (independent) as having limited ADL, nearly 50% of patients were ADL-limited with regard to “walking 600 m,” which would influence their activities in the periphery of their home, such as shopping. When sorted by level of difficulty based on the percentage of the ADL limitation, the highest item was “climbing stairs (to the third floor)” at 70%, followed by “walking one kilometer” at 60% [45].

Fig. 6.15
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The questionnaire on perceived mobility difficulty. This questionnaire on perceived mobility difficulty for hemodialysis patients comprises 12 items divided into the following three categories, which were obtained by a factor analysis: “basic ADL,” “ambulation,” and “walking up or down stairs.” ADL activities of daily living

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Fig. 6.16
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Histogram of ADL dependency and ADL difficulty scores in hemodialysis patients. (a) ADL dependency was assessed by the Functional Independence Measure. (b) ADL difficulty was assessed by the questionnaire on perceived mobility difficulty. ADL activities of daily living

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Fig. 6.17
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Distribution of 12 items of the questionnaire on perceived mobility difficulty in hemodialysis patients. The distribution indicates the ADL difficulty levels when sorted by level of difficulty based on the percentage of the ADL limitation (3 or under) for 216 hemodialysis patients

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Additionally, as a follow-up survey, we reviewed the prognoses according to the tertiles of the ADL difficulty scores that we had developed above and found that the group with the greatest level of difficulty had a mortality risk nearly four times that of the group with the least difficulty. In this way, ADL difficulty evaluation is a simple alternative method to assess the functional status and to predict subsequent prognoses in hemodialysis patients [19].

6.6 The Practice of Exercise Therapy as Disease Management

6.6.1 Protocol of Exercise Therapy (Flow Chart)

Figure 6.18 shows a therapeutic exercise flowchart developed by the authors and colleagues. The criteria (patient conditions) for implementation of this protocol include: those who have not been hospitalized in the past 3 months, those who are undergoing stable dialysis treatment, and those recognized as clinically stable by their attending physician. In practice, this exercise flowchart begins with classifying patients who should do exercise therapy based on periodic assessment data for their physical functions, physical activity levels, and ADLs. In this first classification (as discussed in Sects. 6.4 and 6.5), patients are sorted by those whose indicators are not declining: leg muscle (knee extensor) strength and walking speed for physical function, number of steps for physical activity level, and difficulty in ADLs. The cutoff points for this categorization are as follows: 40% of body weight for leg strength [28]; maximum walking speeds of 90 m/min (1.5 m/s) [29] or comfortable walking speeds of 60 m/min (1.0 m/s) [32], or 48 m/min [31] for walking speeds; 4000 steps on non-dialysis day [33]; and no increase (no adverse change) in the ADL difficulty level. Other physical performance tests and cutoff points are listed in Table 6.1 [30, 36, 46,47,48,49].

Fig. 6.18
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Therapeutic exercise flowchart for hemodialysis patients. ADL activities of daily living

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Table. 6.1 Physical performance tests and cutoff points for discriminating poor performance in patients with chronic kidney disease
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As a result of the above categorization, those not determined to have a decline in any of the above items (indicators) are instructed to continue their current self-management without adding any specific exercise therapy. However, those who have a decline in any of the items are asked to undergo an exploration of the causes after a detailed examination of the changes in their symptoms, complications, and treatment content, in addition to periodic diagnostic assessments by their doctor. When causes are determined, medical treatment is justifiably given priority, but in many other cases, there are no clear reasons, with many seeing a gradual decline after a short-term hospitalization (up to 1 week) or activity limitations due to shunt issues or infections. In these cases, patients are asked to gradually progress in exercise therapies while monitoring in detail any changes in symptoms.

The most important points, as mentioned in a statement in the K/DOQI Clinical Practice Guidelines (2005) [14], are to periodically conduct physical function, activity level, and ADL assessments every 6 months, as well as showing the results of these periodic assessments to each patient individually, having the patient understand their own situation, and allowing patients to manage their own progression [50]. This process then leads to improved adherence to the exercise therapy program.

6.6.2 The Therapeutic Exercise Program in Practice

As shown in the therapeutic exercise flowchart of Fig. 6.18, exercise training program is prescribed for those patients who are determined as having a functional decline if it is necessary and safe for them to engage in exercises. Moreover, exercise training prescriptions should be individualized to the patient’s physical function with an emphasis placed on regular engagement and evaluation of progress. There are primarily two options: unsupervised exercise (instructing the patient to do the exercises at home on non-dialysis days) or supervised exercise (conducting the exercises under the supervision of medical staff such as a physical therapist). The authors take full advantage of the physical conditions of having patients come for hemodialysis outpatient treatment three times per week for implementation of therapeutic exercise. In principle, individual therapeutic exercise sessions are performed under the supervision of a physical therapist by using short periods of 10 or 15 min before the start of the patients’ hemodialysis treatments at dialysis day. Earlier, many studies reported that the adherence to exercise, that is, the rate of continuation of exercise implementation, is poor under unsupervised condition than under supervision [51, 52]. It has been also suggested that the amount of exercise plays a significant role in attaining health-related benefits, namely, using the time before treatment on dialysis day means that they would have a minimum frequency of three times per week for conducting therapeutic exercises. This makes it possible to attain the target level of physical function relatively early, as well as the levels of everyday physical activity and ADLs. Figure 6.19 shows a scene in which an outpatient is performing individualized exercise programs before the start of hemodialysis treatment on a dialysis day.

Fig. 6.19
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Supervised exercise programs aimed at improving leg muscle strength and balance. This patient performs individualized exercise programs before the start of hemodialysis treatment on a dialysis day

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Exercise recommendations for patients with end-stage renal disease are suggested based on the FITT principle: frequency, intensity, time, and type [50, 53, 54]. To summarize, patients should exercise 2–3 times per week at the beginning of the training; the frequency can then be increased to 3–5 times per week. Intensity should be tailored according to patient tolerance to exercise and should be gradually increased. The duration of exercise should be progressively increased depending on the physiological and physical condition. The types of exercises should include aerobic, resistance, flexibility, and balance exercises.

However, frail elderly hemodialysis patients encounter patient-related and structural barriers in exercising, including time restriction associated with continuous dialysis treatment, limited physical capacity, low adherence to conventional exercise programs, and lack of social interaction and support, and challenges in the physical environment [50, 55, 56]. In recent years, therapeutic exercise has been developed within hemodialysis treatment times (after treatment begins), and its safety and results have been verified [51, 57]. This can be a useful option for patients who do not have time before the start of hemodialysis treatment, or in cases where vital signs such as blood pressure are not stable (Fig. 6.20). Moreover, recent studies reported that intradialytic electrical muscle stimulation can improve muscle strength, exercise capacity, and quality of life (QOL) in hemodialysis patients [58,59,60]. Electrical muscle stimulation is a new method for exercise therapy that can be used by patients while lying down; this method has no time restriction, requires no volitional effort, and places no hemodynamic stress on the patient (Fig. 6.21).

Fig. 6.20
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Intradialytic exercise. This patient performs aerobic training using a cycle ergometer during her hemodialysis treatment

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Fig. 6.21
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Muscle strengthening exercise using electrical muscle stimulation. The right photograph shows a scene performing an intradialytic exercise using electrical muscle stimulation

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6.6.3 Long-Term Effect of Introducing a Disease Management System

The K/DOQI Clinical Practice Guidelines (2005) [14] include a statement that periodic physical function assessment and encouragement for participation in physical activity should be part of disease management for dialysis patients, but there have been very few reports verifying the outcomes of introducing these systems in practice. The author and colleagues introduced the flowchart shown in Fig. 6.18 over a period of roughly 10 years and verified the prognoses in hemodialysis patients who have been in this system for 3 years retrospectively [61]. Those results showed that high attendance (>75% attended) group had significantly lower mortality rates and rates of cardiovascular events compared to low attendance (≤75% attended) group (Fig. 6.22). In this way, it was shown that a system of periodically conducting physical function evaluations as a part of disease management protocols and intervening individually based on that data brings about effective outcomes in terms of long-term prognoses.

Fig. 6.22
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The prognoses after introducing a disease management system (see Fig. 6.19) for hemodialysis patients. Kaplan–Meier analysis of survival (a) and cardiovascular events (b) in 266 patients undergoing hemodialysis. The high attendance group (attended >75% of all available sessions in the management program) had significantly better survival and lower incidence of cardiovascular disease than the low attendance group (≤75% attendance)

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6.7 Future Topics

Over the course of the past 10 years, many systematic reviews have been published that focus on CKD patients who have started dialysis treatment [57, 62,63,64,65]. However, they all have a relatively young average age of <60 years, and in which there have been very few trials actually evaluating the impact of exercise on frailty regarding elder frail patients with end-stage renal disease treated with hemodialysis [66, 67]. Furthermore, there have been few reports using prospective, randomized, and controlled trials or exercise therapy. The EXerCise Introduction to Enhance performance in dialysis patient trial (EXCITE) demonstrated the effectiveness of a 6-month personalized, home-based walking exercise program to improve walking capacity and muscle strength compared to “usual care” [64, 68]. However, this multicenter randomized, controlled trial in the dialysis population revealed that during the 6 months of training, 31% of participants withdrew from the exercise group compared with 15% from the placebo, and 47% of those who completed the study were designated as having low adherence to the protocol (<60% of sessions). Therefore, further study is needed to develop an effective strategy for promoting adherence rates to exercise therapy in frail elderly hemodialysis population, namely, there are many issues that remain unclear for senior dialysis patients.

In recent years, the age of patients starting hemodialysis treatment is gradually increasing. The content of this chapter (exercise therapy as disease management) can be summarized as frailty prevention, but developing frailty is not only attributable to physical functions but is also related to nutritional conditions, mental functions (cognitive functions), psychosocial aspects, and environmental factors. It is anticipated that these proportions of patients will increase as the population aging progresses. In summary, dialysis patients are in certain need of comprehensive care “renal rehabilitation.”

6.8 Conclusion

Based on the survey the author and colleagues conducted previously, approximately 70% of Japanese elderly patients with hemodialysis are in a state of frailty or prefrailty, and physical functions and physical activity level of Japanese elderly patients attending the dialysis clinic for outpatient care decrease to approximately 50–70% of those of healthy persons. Moreover, a clear decline in physical functions and physical activity level is a significant and independent risk factor that worsens prognosis. The authors and colleagues developed the questionnaire on perceived mobility difficulty to accurately grasp limitations in ADL and revealed that the ADL difficulty evaluation is a simple alternative method to assess the functional status and to predict subsequent prognosis in elderly hemodialysis patients. The authors also have introduced a disease management system consisting of periodic assessment and exercise therapy and clarified that the high attendance group in the management program had significantly better survival and lower incidence of cardiovascular disease than the low attendance group. Therefore, periodic physical function assessment and encouragement for participation in physical activity should be part of disease management for frail hemodialysis patients.