THE EFFECT OF PHYSICAL ACTIVITY DURING HEMODIALYSIS ON PHYSICAL FUNCTION, QUALITY OF LIFE PARAMETERS AND PATIENT-REPORTED OUTCOME MEASURES

The usefulness of intradialysis physical exercise has been widely acknowledged, although is comparative efficacy on patient reported outcomes remains  uncertain. The aim of study was to investigate the impact of cyclic intradialysis training on quality of life, patient-oriented outcomes and physical functioning tests.

The primary endpoint of single-center, interventional, comparative, prospective study was the change in the 6-minute walk test (6MWT) after 6 months of intradialysis physical training (IDT). Secondary outcomes included other physical performance tests, the Dialysis Symptom Index (DSI), and quality of life. In the study group, IDT were conducted under the physical therapist supervision during the second hour of each HD session. This included a warm-up (5-6 min), a main exercise (10-15'), and a cool-down (5'), total duration up to 30' per session. The exercises intensity was graded by Borg scale (7-8 for warm-ups, 10-12 for main exercises, and 8-9 for cool-downs). We used a portable exercise bike, adapted to the dialysis chair. Quality of life was assessed by KDQOL-SF questionnaire, after excluding patients with significant depression as assessed by Beck scale. Patient symptoms were evaluated using the Dialysis Symptom Index. Physical function was evaluated using a 6MWT and a series of physical performance tests: "standing-up and siting-down 5 times from a chair", "maintaining balance in tandem positions  for 10 seconds", and "gait speed from a standing position over 4 meters"

The study randomly selected 15 patients with stable dialysis regimen for more than 3 months who achieved the targets for azotemia and anemia correction (eKt/V>1.4; Hb 10-12 g/dL). The inclusion criteria also required the consent to participate in a series of questionnaires during the study (follow-up 6-12 months). The control group (45 patients matched for age, gender, and KRT duration) received the same treatment, but without IDT.

The safety vital signs and changes in physical performance measures are presented in Table 1.

IDT improved some scales of KDQOL-SF: Effects of kidney disease by 9.9 (11.1) points, p=0.004; Quality of social interaction by 15.6 (21.8), p=0.015; Patient satisfaction by 19.4 (22.2), p=0.004; Emotional well-being by 15.3 (17), p=0.004 as well as SF-12 Mental Composite Summary (MCS) by 7.8 (8.9), p=0.005. The Beck Depression Inventory decrease by 3.8 (4.8), p=0.008. Spielberger-Hanin anxiety test results (situational and personal) improved by 5.3 (8.9), p=0.037 and 7.2 (8.4), p=0.005 points. In IDT group, the 6MWT significantly increased. The decrease in heart rate and respiratory rate before and after exercise indicates an improvement in exercise tolerance. The DSI changes are presented in the Table 2.

IDT improved 8 out of 30 symptoms in DSI, with 2 worsening and 18 remaining unchanged; two out of four main symptom clusters showed improvement. There was a correlation between changes in DSI and MCS (r=0.511 [95% CI 0.002, 0.810], but not Physical Component Summary. The correlation between changes in specific symptom evaluations and changes in primary KDQoL scales was weak. These methods likely reflect different aspects of the patient-reported outcome measures and should be analyzed separately

Intradialysis physical training can improve physical function, quality of life and patient-reported outcome measures