Addressing Frailty in the ESKD Population through Professionally Guided In-Center Exercise Programs

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A 71-year-old woman began using three-times-weekly hemodialysis (HD) 8 months ago and reports worsening fatigue, along with increasing difficulty with her activities of daily living. She is fearful that loss of independence will require her to move to a nursing facility. As her renal failure progressed over the past year she experienced complications that required repeated hospitalizations. After each discharge, she has reported feeling even weaker. She has declined prior offers of inpatient rehabilitation and has struggled with coordinating in-home physical therapy. She wants to exercise and improve her physical function, but she has a fear of falling. In addition, she is no longer certain about what exercises would be best for her or what her body is capable of doing.

Prevalence of frailty in the ESKD population

Whereas frailty is something that patients and clinicians may broadly discuss, many have tried to detail the various components that define the condition. The current standard measurement was developed by Fried et al. (1), focusing on four domains of frailty: unintended weight loss, low physical activity, weakness, and poor endurance. Patients with ESKD receiving in-center HD experience high rates of frailty, physical inactivity, and mortality. Whereas the prevalence of frailty in older adults (>65 years old) in the community-dwelling population has been measured around 7% (1), in those undergoing in-center HD the prevalence has been found to be as high as 73% (2). The younger (<65 years old) HD population also has a very high prevalence of frailty, measured in prior studies at 36% (3).

Frailty and mortality in the ESKD population

In a study that defined frailty using the Fried Frailty Index for the HD population, frailty was associated with a 40% 3-year mortality compared with the rate of 16% in a similar nonfrail ESKD population (3). Overall, this correlated with a hazard ratio of 2.7 for greater risk of death independent of age, sex, comorbidity, and disability. The various components of frailty (weight loss, exhaustion, low physical activity, weak grip strength, and slow gait speed) individually have shown to be a negative predictive factor for patient health. This risk increased more than fivefold for patients with all five components (4). Exercise has been promoted as a way to combat or slow the progression of frailty across many diseases and age groups. However, achieving exercise in the ESKD patient population remains challenging.

The history of exercise and dialysis

Intradialytic exercise has been the subject of several investigative studies over the past several decades. A Cochrane systematic review in 2011 found significant benefit in patients’ aerobic capacity, resting blood pressure, and health-related quality of life from exercising three times per week for longer than 30 minutes per HD session (5). There have been several examples in the literature of exercise studies and subsequent meta-analysis that have shown improvement in many of the physical fitness tests used to measure frailty. These tests include the 6-minute walk test, the Timed Get Up and Go Test, the Maximum Walking Speed Test, the Sit to Stand Test, and overall metabolic equivalents achieved (6–9). These exercise routines usually involve either aerobic exercise, resistance exercise, or a combination of the two for at least 30 minutes during the first 2 hours of each HD session. Even the use of resistance exercise with elastic bands alone has been shown to improve the patient’s 30-second Sit to Stand Test and 8-foot Timed Get Up and Go Test (10).

Considerations for intradialytic exercise in the modern HD center

Despite these reported benefits of exercise, there do not appear to be any formal intradialytic exercise protocols in the United States. The main barriers in this country are thought to be interference with the workflow of an outpatient dialysis center and also concern for high rates of patient nonadherence and dropout.

A recent study of an intradialytic exercise biking program in the United Kingdom noted an adherence of 78% at 3 months that decreased to 63% by 12 months (11). One of the only papers to evaluate longer-term adherence was a German single-center study involving exercise professionals that measured 1-year and 5-year adherence at 78% and 43%, respectively (12).

Unfortunately, data on exercise adherence and efficacy in the United States are lacking. This remains a challenge across the world, given that nephrologists and dialysis center staff are thought to lack the personnel and resources needed to advise dialysis patients on individualized exercise regimens (13). A recent study in CJASN evaluated the perceived barriers and desired outcomes in 280 in-center HD patients. Improved energy, strength, and maintenance of independence were the top goals for in-center patients, and younger patients were very motivated by the potential for kidney transplantation. In this survey, the top perceived barriers to exercise were mostly related to physical symptoms such as shortness of breath, tiredness, and weakness. Secondary barriers included not knowing how to construct an exercise program, not knowing what exercises are safe, affordability, and lack of travel and time (14). It is these secondary barriers that we hope can be addressed and mitigated by a sponsored in-center program that provides individualized exercise programs under the guidance of exercise professionals.

Successful programs

Prior efforts at intradialytic exercise studies have been successful in using both aerobic and resistance exercises. Some highlights from those selected studies are as follows:

• ■ Beneficial effects of intradialytic cardiopulmonary rehabilitation, Guio et al. (7)

  • □ Prospective trial with 18 patients in Brazil

  • □ Treated for 8 months with intradialytic cycle ergometer

  • □ Showed improvement in 6-minute walk test and left ventricle ejection fraction

  • □ No change in baseline heart rate and BP determinations; improvement in bodily pain and vitality noted by patients

• ■ Effects of an intradialytic exercise resistance training program on physical function, Bennett et al. (10)

  • □ Recruited 171 participants across 15 dialysis units in Australia

  • □ Treated with progressive resistance band exercises under guidance of an accredited exercise professional for 12 to 48 weeks

  • □ Patients showed improvement in Sit to Stand Test and Timed Get Up and Go Test

More research is needed to demonstrate the effects of an exercise program over a longer period to examine endpoints such as hospitalizations, falls, and mortality. If improved functional status and quality of life are among the highest priorities for patients, a value-based performance healthcare system in addition seeks to reduce hospitalizations. If this can be demonstrated, then the introduction and permanent presence of an exercise program in a dialysis center would likely be part of care delivery in the future, providing benefits to patients and including economic gains.