Publications

Chronic kidney disease (CKD) is highly prevalent in the United States and throughout the world,(1) with approximately 13% of adults affected.(2) In addition, according to recent estimates, almost half of patients with CKD stages 3 to 5 are 70 years of age and older.(2) In the United States, the number of prevalent end-stage renal disease cases continues to increase in patients older than age 65. In light of the demographic characteristics of patients with CKD and ESRD, there has been considerable focus on associations between CKD and cardiovascular outcomes.(3) Until recently, less attention had been paid to other consequences of CKD in general and among older individuals with CKD in particular, but there is now solid evidence linking CKD with impairments of physical function, cognitive function, and emotional function and quality of life. This review summarizes available literature on these topics, focusing specifically on physical functioning and frailty, cognitive function, emotional health, including depression and anxiety, and health-related quality of life.

Frailty is a distinct phenotype that is highly prevalent in chronic kidney disease (CKD) and appears to be more prevalent with decreasing glomerular filtration rate. Exercise training or intervention to increase physical activity may ameliorate poor physical functioning and frailty, and even may improve survival in patients with CKD. Although exercise interventions improve outcomes across the spectrum of CKD, including patients treated with dialysis, patients treated with dialysis face barriers to exercise that patients with predialysis CKD do not. Rehabilitation at earlier stages of CKD (or prehabilitation before dialysis) might be more beneficial than not addressing the decreasing physical functioning and low physical activity until patients are receiving dialysis. This review summarizes available literature on frailty in the CKD and end-stage renal disease population, including exercise interventions and the limited evidence for prehabilitation as a strategy.

Introduction

Patients on hemodialysis experience a heavy burden of symptoms that may be related to the low levels of physical activity reported in this population. We hypothesized that physical activity would be inversely related to symptom severity and that depression might mediate this association.

Methods

We designed a cross-sectional study of 48 patients receiving hemodialysis at 3 San Francisco dialysis clinics. Physical activity was measured using pedometers and recorded within 1 week of symptom assessment. Symptoms were assessed using total symptom burden and severity on the Dialysis Symptom Index (DSI; burden 0-29, severity 0-145), individual symptoms on the DSI (0-5), Kidney Disease Quality of Life Vitality scores, (0-100), and the Center for Epidemiologic Study-Depression (0-60).

Results

Median daily step count was 2631 (25th, 75th percentile 1125, 5278). Seventy-three percent of patients reported fatigue. After adjustment for age, sex, diabetes, and serum albumin, physical activity was associated with 0.2 points lower fatigue severity per 1000 steps per day (95% confidence interval [CI] -0.3 to 0.0), = 0.04. Physical activity was also associated with higher Vitality score (2.36 points per 1000 steps; 95% CI 0.07-4.65) and lower insomnia scores (-0.1 points per 1000 steps; 95% CI -0.3 to 0.0], < 0.05) in our adjusted models. Physical activity was not associated with other symptoms.

Conclusion

Because the study was cross-sectional, we cannot determine whether physical activity lowers fatigue and insomnia or whether less insomnia and fatigue increase physical activity. However, interventions to increase physical activity should be considered alongside current strategies as a possible approach to managing fatigue and insomnia.