Exercise Activity to Improve Mobility in Patients With CKD and PAD

People affected by chronic kidney disease and concomitant diagnosed peripheral artery disease at intermediate stages, without contraindications to exercise therapy will be invited to participate in the study.

Whose providing informed consent, will be randomly assigned to one of two groups:

1. Exercise program receiving two daily 10-minute interval walking sessions at a slow increasing speed.
2. Control group: receiving usual care including optimal medical therapy and nutritional advice.

Patients of both groups will be measured at baseline, after the end of the exercise program (6-month) and at follow up (12-month). Outcome measures will include walking ability by the 6-minute walking test (primary outcome) and lower limbs perfusion, body composition, quality of life, laboratory outcomes and long-term hospitalizations.

People with chronic kidney disease (CKD) are exposed to a high risk of developing peripheral artery disease (PAD) and its related adverse health outcomes. This dangerous combination of pathological conditions increases overall cardiovascular risk, mortality and lower limbs amputations.

The scientific literature suggests a strategic co-management of CKD-PAD patients by multidisciplinary teams including specialists of different areas and expertise. Indeed, a common issue is that both these diseases are negatively associated with a sedentary behavior. Exercise therapy may enhance the physical functioning, the risk factors management, the lower limbs vascularization and reduce the cardiovascular risk that affects this population. Since the CKD-PAD population is less likely to be provided recommended optimal care, and considering that 2 out of 3 CKD patients have a completely sedentary behavior for several barriers to training participation, proper exercise programs should be developed. This multicenter randomized-controlled trial aims to test the effectiveness of a 6-month home-based structured walking program on physical functioning and laboratory and clinical outcomes. Purposely 100 CKD patients at KDOQI stages III or IV with concomitant PAD at Rutherford's stages I to III, aged \> 18 years and without absolute contraindications to exercise training will be randomized to receive an exercise intervention (Ex) or usual care (Control, Co). The 6-month training intervention, previously tested in PAD and CKD patients, consist in two 10-minute daily interval walking sessions performed inside the home.

Patients will receive a detailed exercise prescription according to their baseline walking capacity, with the walking speed maintained at home through sound pacing by a digital metronome. The prescribed speed will be weekly increased from the 60 to the 100% of their baseline walking speed with a fixed working time throughout the program. Two serial visits during the program will be scheduled to reinforce adherence to exercise, maintained and verified by a digital application, and to control the blood pressure. Patients enrolled in the Co group will receive standard CKD-PAD care, including optimal medical therapy and nutritional advices.

The primary outcome of the study will be the variations of mobility as assessed by the 6-minute walking test at the end of the program. Secondary outcomes will include lower limbs perfusion and strength, body composition and bone mineral density, quality of life, laboratory outcomes including rate of progression of CKD and the long-term hospitalizations and mortality.

Outcome measures will be assessed by blinded operators at baseline, at the end of the program for exercise group (6-month) and at 12 months follow up.

Eligibility Criteria:
Inclusion Criteria:

* chronic kidney disease at KDOQI stages III or IV and concomitant Peripheral artery disease at stages I, II, III;
* ability to walk independently;
* cognitive function to give informed consent identified by a Mini Mental Status Examination score greater or equal to 20/30
* absence of clinical conditions contraindicating exercise therapy (e.g., unstable angina, severe heart failure at NYHA class IV, anemia with lower than 10.0 g/dl).

Exclusion Criteria:

* major amputations;
* major surgery planned in the next 3 months;
* known comorbid conditions that may limit survival to less than 2 years;
* inability or unwillingness to comply with protocol requirements.