Bone mineral density after exercise training in patients with chronic kidney disease stages 3 to 5: a sub-study of RENEXC-a randomized controlled trial.

Background: We evaluated the effects of 12 months of exercise training on bone mineral density (BMD) in patients with chronic kidney disease (CKD) stages 3-5 not on kidney replacement therapy (KRT). Methods: A total of 151 patients were randomized to 12 months of either balance or strength training, both together with endurance training. Some 112 patients completed and 107 (69 men, 38 women) were analysed, with a mean age 66 ± 13.5 years and 31% having diabetes. The exercise training was self-administered, prescribed and monitored by a physiotherapist. Total body, hip and lumbar BMD, T score and Z score were measured at baseline and after 12 months using dual energy X-ray absorptiometry. Results: Both groups showed increased physical performance. The prevalence of osteoporosis and osteopenia was unchanged. The strength group (SG) decreased total body BMD (P < .001), the balance group (BG) increased total body T score (P < .05) and total body Z score (P < .005). Total body ΔT score was negative in the SG and unchanged in the BG (P < .005). Total body ΔZ score was negative in the SG and positive in the BG (P < .001). The proportion of progressors measured by ΔT (P < .05) and ΔZ scores (P < .05) was significantly lower in the BG compared with the SG. In multivariate logistic regression analysis, belonging to the BG was the only factor with a lower risk of deterioration of total body BMD, T and Z scores. Conclusions: Twelve months of balance training together with endurance training seemed to be superior to strength training in maintaining and improving BMD in patients with CKD not on KRT.

Randomized Controlled Trial of Exercise in CKD-The RENEXC Study.

INTRODUCTION: Home-based, clinically feasible trials in non-dialysis-dependent patients with chronic kidney disease (CKD) are sparse. We compared the effects of 2 different exercise training programs on physical performance, and measured glomerular filtration rate (mGFR) and albuminuria level in patients with CKD stages 3 to 5. METHODS: This is a single-center, randomized controlled trial (RCT) comprising 151 patients (mGFR: 22 ± 8 ml/min per 1.73 m2; age 66 ± 14 years) randomized to either balance or strength training. Both groups were prescribed 30 minutes of exercise per day for 5 days per week for 12 months, comprising 60 minutes per week of endurance training and 90 minutes per week of either strength or balance exercises. The exercises were individually prescribed, and the intensity was monitored with Borg's rating of perceived exertion (RPE). RESULTS: There were no treatment differences for any of the primary outcomes measuring physical performance. The strength and balance groups showed significantly increased effect sizes after 12 months for the following: walking (31 m and 24 m, P < 0.001) and the 30-second sit-to-stand test (both: 1 time, P < 0.001); quadriceps strength (right/left: strength 1.2/0.8 kg*m, P < 0.003; balance 0.6/0.9, P < 0.01); functional reach (both: 2 cm, P < 0.01); and fine motor skills (open/closed eyes, right/left, both: between 0.3 and 4 seconds faster, P < 0.05). After 12 months, there was a significant treatment difference for albuminuria (P < 0.02), which decreased by 33% in the strength group. In both groups, mGFR declined by 1.8 ml/min per 1.73 m2. CONCLUSION: Our primary hypothesis that strength training was superior to balance training was not confirmed. Within groups, 12 months of exercise training resulted in significant improvements in most measures of physical performance. Measured GFR declined similarly in the 2 groups. The strength group showed a significant decrease in albuminuria.

Comparing effects of 4 months of two self-administered exercise training programs on physical performance in patients with chronic kidney disease: RENEXC - A randomized controlled trial.

BACKGROUND: Exercise training is recommended to patients with chronic kidney disease (CKD). However, the level of evidence is still low. This randomized controlled trial (RCT) compared two different and self-administered exercise training programs in a representative CKD population. METHODS: This single centre RCT included 151 non-dialysis dependent CKD patients, irrespective of age and comorbidity. Self-administered exercise training of 150 minutes per week was prescribed for 4 months and consisted of 60 minutes endurance training in combination with 90 minutes of either strength or balance training (strength versus balance group). Overall endurance (6-minute walk-test (6-MWT), stair climbing), muscular endurance (30-seconds sit-to-stand (30-STS), heel rises and toe lifts, handgrip (HGS) and isometric quadriceps (IQS) strength, balance (functional reach (FR) and Berg´s balance scale (BBS)) and fine motor skills (Moberg´s picking up test (MPUT)) were measured at baseline and after 4 months. Intention to treat analyses with mixed models was used. RESULTS: 53 women and 98 men, mean age 66 ± 14: range 19 to 87 years, eGFR 20 ± 7: range 8 to 48 ml/min/1.73m2 participated. The strength group (n = 76) improved significantly in 6-MWT, stair climbing, 30-STS, heel rises right and left, toe lifts right, IQS right and left, and MPUT with closed eyes with the right and left hand. The balance group (n = 75) improved significantly in heel rises right and left, IQS left, BBS and left-handed MPUT with open and closed eyes. A significant effect between the groups was found for IQS right. CONCLUSIONS: Two different exercise training programs, consisting of endurance in combination with either strength or balance exercise training, improved or maintained overall endurance, muscular strength and endurance, balance and fine motor skills after 4 months of 150 minutes/week self-administered exercise training in a representative CKD population, regardless of age and comorbidity.

Sarcopenia and relationships between muscle mass, measured glomerular filtration rate and physical function in patients with chronic kidney disease stages 3-5.

Background: Sarcopenia and poor physical function are common in patients with chronic kidney disease (CKD). Our aim was to investigate the relationships between muscle mass and measured glomerular filtration rate (GFR) and between muscle mass and strength and balance, respectively, in patients with CKD stages 3-5. Methods: This is a baseline data analysis of a randomized controlled clinical trial. A total of 148 adult patients with an estimated GFR <30 mL/min/1.72 m2, not on renal replacement therapy, irrespective of the number of comorbidities were included from the Department of Nephrology, Skåne University Hospital, Lund, from 2011 to 2016. Body composition was measured by dual-energy X-ray absorptiometry (DEXA). GFR was measured by iohexol clearance. Balance was measured by functional reach and the Berg balance test and strength by handgrip strength and isometric quadriceps strength. Results: Measured GFR ranged from 8 to 55 mL/min/1.73 m2. Lean mass (P < 0.05), fat mass (P < 0.05), appendicular skeletal muscle (P < 0.001) and appendicular skeletal muscle index (P < 0.05) were associated with GFR. Functional reach was associated with leg lean mass (P < 0.05) and the Berg balance test score was associated with trunk lean mass (P < 0.05). Handgrip strength was associated with arm lean mass (P < 0.001). Isometric quadriceps strength was associated with leg lean mass (P < 0.001). More men (44%) suffered from low muscle mass than women (22%), whereas more women (36%) suffered from low muscle strength than men (26%). However, when combining both, men (16%) suffered from sarcopenia to a greater extent than women (8%). Conclusions: Among patients with CKD stages 3-5, loss of lean body mass, especially appendicular skeletal muscle, was significantly related to GFR decline. Two important markers of physical function, balance and strength, were significantly related to muscle mass. Moreover, men were more prone to sarcopenia than women during kidney function decline.

Decline in measured glomerular filtration rate is associated with a decrease in endurance, strength, balance and fine motor skills.

AIM: Physical performance in chronic kidney disease affects morbidity and mortality. The aim was to find out which measures of physical performance are important in chronic kidney disease (CKD) and if there are associations with declining measured glomerular filtration rate (GFR). METHODS: Endurance was assessed by 6 min walk test (6-MWT) and stair climbing, muscular endurance by 30 s sit to stand, heel rises and toe lifts, strength by quadriceps- and handgrip-strength, balance by functional reach and Berg's balance scale, and fine motor skills by Moberg's picking-up test. GFR was measured by Iohexol clearance. RESULTS: The study comprised 101 patients with CKD 3b-5 not started dialysis, 40 women and 61 men, with a mean age of 67 ± 13 (range: 22 - 87) years. All measures of physical performance were impaired. A decrease in GFR of 10 mL/min per 1.73 m2 corresponded to a 35 metre shorter walking distance in the 6-MWT. Multivariable linear regression analysis showed significant relationships between decline in GFR and the 6-MWT (P = 0.04), isometric quadriceps strength left (P = 0.04), balance measured as functional reach (P = 0.02) and fine motor skills in the left hand as measured by Moberg's picking-up test (P = 0.01), respectively, after sex, age, comorbidity and the interaction between sex and age had been taken into account. CONCLUSION: Endurance, muscular endurance, strength, balance and fine motor skills were impaired in patients with CKD 3b-5. Walking capacity, isometric quadriceps strength, balance, and fine motor skills were associated with declining GFR. The left extremities were more susceptible to GFR, ageing and comorbidities and seem thus to be more sensitive.