SO068EFFECTS OF BASELINE PHYSICAL FUNCTION AND 12 MONTHS EXERCISE TRAINING ON SURVIVAL IN PATIENTS WITH NON DIALYSIS DEPENDENT CHRONIC KIDNEY DISEASE
Authors: Denguir Sara , Hellberg Matthias , Rydell Helena , Almquist Martin , Clyne Naomi 
Published: June 2020

Abstract

Background and Aims
Low physical function is associated with increased mortality in patients on dialysis. Observational studies have shown an association between self-reported physical activity and survival in patients with chronic kidney disease (CKD). It is unclear whether exercise training can affect survival in patients with CKD. The purpose of this study was to investigate, whether level of physical function and exercise training, respectively, affect survival in patients with non-dialysis dependent CKD stages 3-5.

Method
The patients studied had participated in the RENEXC study comprising 12 months of endurance training in combination with either strength- or balance training. In this study the whole group was analyzed as both groups had improved their physical function with no between group differences. Physical function at baseline and after 12 months was assessed with a battery of tests. Patients were divided into 4 groups for each test: improved physical function by &gt;10 %, no improvement, did not complete 12 months of exercise training and missing data. Effects of physical function at baseline and improvement in physical function after 12 months of exercise training on survival were analyzed using univariate and multivariate Cox regression analyses. Multivariate analyses were adjusted for age, sex, co-morbidity, time on dialysis and time as transplanted.

Results
This study comprised 151 patients, mean age 66±14 years, 65% men, measured GFR 22.5±8.2 ml/min/1.73 m2. Median follow-up was 60 months.
Physical function at baseline was associated with a significantly better survival in univariate Cox regression analysis in the following tests: 6 Minute Walk Test (6MWT), handgrip strength right, functional reach and 30 seconds Sit-To-Stand (30s-STS). The decline in hazard ratio (HR) per unit in each test was 0.5 % in the 6MWT, 2.9 % in handgrip strength, 6.4 % in functional reach and 10.8 % in 30s-STS. Multivariate analyses showed that only 6MWT and 30s-STS were significantly related to survival. The decline in hazard ratio (HR) per unit in the multivariate analyses was 0.4 % in the 6MWT (HR 0.996, CI 0.994-0.998) and 5.7 % in 30s-STS (HR 0.943, CI 0.892-0.996).
Patients who completed 12 months of exercise training and improved their results by 10 % or more showed a significantly better survival compared with patients who completed 12 months of exercise training but failed to improve by at least 10 % in the following tests in the univariate analyses: handgrip strength right and left, isometric quadriceps strength left and 30s-STS. There was also a significantly better survival in the group that improved compared with the group that did not complete 12 months of exercise in the 6MWT, handgrip strength right and left, isometric quadriceps strength left and 30s-STS. In the multivariate analyses there were no significant differences between the group that improved and the group that did not improve in any of the physical function tests. The significant differences between the group that improved and the group that did not complete remained in the following tests: handgrip strength right (HR 7.83, CI 2.10-29.2) and left (HR 3.95, CI 1.31-11.9), isometric quadriceps strength left (HR 3.94, CI 1.78-8.74) and 30s-STS (HR 3.50, CI 1.58-7.77). The difference between the group that improved and the group that did not complete the training became significant in functional reach (HR 4.22, CI 1.99-8.94) and isometric quadriceps strength right (HR2.80, CI 1.35-5.80).

Conclusion
After adjustment for age, sex, co-morbidity, time on dialysis and time as transplanted overall endurance and muscular endurance at baseline were associated with a better survival. Patients who improved muscle strength, muscular endurance and balance showed a better survival compared with those who did not complete the study. There were no statistically significant differences between those who improved their physical function by at least 10% compared with those who did not.