The Effect of Exercise Therapy on Physical Function, Biochemistry and Dialysis Adequacy in Haemodialysis Patients: A Systematic Review and Meta-Analysis

Abstract

Background: Patients undergoing dialysis have high mortality rates and a unique risk factor profile. Some improvements elicited by exercise training have been shown in dialysis populations, here we aimed to further explore the benefits of exercise. As well as changes in physical fitness we quantified cardiac function, depression, serum biochemistry, dialysis adequacy and energy intake following exercise training in people with chronic kidney disease (CKD) undertaking dialysis. Methods: A systematic literature search was completed in December 2012 identifying randomized, controlled trials of exercise training studies in haemodialysis (HD) patients. A subsequent meta-analysis was conducted. Results: Twenty four studies were included, totalling 879 patients. Exercise training produced significant improvements in physical fitness: peak VO₂ 5.03 mlO₂·kg⁻¹·min⁻¹ (95% CI 3.73, 6.33, p < 0.0001), Knee extensor strength 2.99 kg (95% CI 0.46, 5.52, p = 0.02) and 6 minute walk distance 60.7 metres (95% CI 18.9, 103, p = 0.004). Significant increases in energy intake MD 238 Kcal·day⁻¹ (95% CI 94, 383, p = 0.001), serum Interleukin-6 MD-0.58 pg·ml⁻¹ (95% CI-1.01, -0.15, p = 0.008) and C-reactive protein MD 0.92 mg/L⁻¹ (95% CI 0.29, 1.56, p = 0.004), but not Albumin or BMI, were reported. Improved Beck Depression scores were reported MD-6.9 (95% CI-9.7,-4.1, p < 0.00001). Dialysis adequacy was reduced MD-0.23 (95% CI -0.29, -0.17, p < 0.00001), while serum potassium was higher MD 0.14 mmol·L⁻¹ (95% CI 0.01, 0.27, p = 0.04). Moreover exercise training appeared safe, with no direct exercise-associated deaths in over 30,000 patient-hours. Conclusions: Our pooled analyses confirmed improvements in physical fitness following exercise training and suggested additional improvements in dialysis efficiency (kt/v), serum potassium, inflammation and depression in HD patients.