Reference Values for Lower-Limb Dynamometry in Patients With Chronic Kidney Disease (REHAD-CKD)

Reference values for Lower Limb Strengh

Lower limb strengh will be evaluated using handheld dynamometer (Lafayette Manual Muscle Testing System Model-01165, Lafayette IN, USA) for hip flexors and hip abductors.Testing will follow a strict structured order: first hip flexors and then hip abductors. Within each muscle group, legs will be alternated, starting with the dominant leg and then the nondominant leg, to allow specific rest periods between muscle groups (15 seconds). Hip flexors will be assessed with the patients with both hips and knees bent. The dynamometer will be placed on the anterior part of the thigh, 2 centimetres below of patella. Hip abductors will be assessed with both legs extended at the hip and knee. The dynamometer will be placed on the lateral part of the thigh, 2 centimetres below of the knee joint line. During both measurements physiotherapist will apply force in the opposite direction of the movement. Unit of measure: Newton (N).

Muscle strength assessment Handgrip

It will use a Jamar® Approved Hydraulic Hand Dynamometer. The participant will be seated in a chair with their back straight and the arm flexed at 90°. The test will be repeated three times for each hand (3-5 seconds), with rest periods between repetitions to avoid muscle fatigue. Unit of measure: Kilogram (Kg). The cut-off points for loss of muscle strength will be set greater than or equal to 27 kg for men and greater than or equal to 16 kg for women, based on values defined by Mathiowetz et al. and included in the European clinical nutrition guidelines as a phenotypic criterion for disease-related malnutrition.

Human Activity Profile

The Human Activity Profile (HAP) consist of 94 questions addressing different domains of daily activity and participation, with three possible answers for each item: 'still doing,' 'stopped doing,' or 'never did.' For each item, the participant will have to choose one of these responses. Based on each answer, two scores will be calculated: the Maximal Activity Score (MAS), which corresponds to the activity with the highest effort demand that the volunteer 'still performs'; and the Adjusted Activity Score (AAS), which will be calculated by subtracting the number of items the subject 'has stopped doing' below the MAS value from the MAS itself. The AAS will provide the value of activity that the subject has ceased to perform compared to what they were doing before. Unit of Measure: Absolute number.

Screening Sarcopenia risk

Screening for Sarcopenia risk will be performed using the "Strength, Assistance with walking, Rise from a chair, Climb stairs, and Falls" (SARC-F) questionnaire, which consists of five self-reported questions based on the subjects' perception of their limitations regarding strength, walking ability, rising from a chair, climbing stairs, and their history and number of falls. Each item will be scored from 0 to 2, where 0 = no difficulty, 1 = some difficulty, and 2 = great difficulty, or if the subject uses devices or cannot perform the task without personal assistance. The total SARC-F score can range from 0 to 10, and subjects with a score ≥ 4 points will be considered at risk of sarcopenia, in accordance with the recommendations of the European consensus on sarcopenia. Unit of Measure: Absolute number.

Frailty assessment using the "Fatigue, Resistance, Ambulation, Illnesses,Loss of Weight" (FRAIL) questionnaire

Frailty will be assessed using the five questions (fatigue, climbing stairs, walking 100 m, comorbidity, and weight loss) that comprise the "Fatigue, Resistance, Ambulation, Illnesses,Loss of Weight" (FRAIL) questionnaire. A score of 1 or higher suggests frailty. Unit of Measure: Absolute Number