Chronic obstructive pulmonary disease (COPD) is complicated by malnutrition in 20-70% of cases. In COPD, low fat-free mass is associated with a higher risk of morbidity and mortality. L-citrulline is a non-protein amino acid that has a direct effect on muscle protein synthesis. Oral supplementation with L-citrulline (10 g/day) in malnourished patients has shown to increase fat-free mass. The effects of L-citrulline supplementation in malnourished COPD patients are unknown. The main objective of this prospective, single-centre, randomised, double-blind, placebo-controlled study will be to determine the impact of 45 days of nutritional supplementation with L-citrulline (10 g/day) on lean body mass (fat-free mass index (in kg.m-2) measured by bioelectrical impedance analysis) in malnourished patients (BMI \< 20 kg/m2 if \< 70 years old or \< 22 kg/m2 if ≥ 70 years old) with COPD at stages 3-4 of the GOLD classification.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
60
to take 1 pod a day for 45 days
Fat Free Mass Index
Fat Free Mass Index (in kg.m-2) measured by bioelectrical impedance analysis
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
Grip strength
Grip strength will be measured using a dynamometer with the patient in a seated position, elbow bent at 90°, shoulders relaxed and forearm in a neutral position. The dynamometer should be held in the dominant hand. The measurement should be taken twice. The highest value will be used.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
Maximum quadriceps strength
The maximum voluntary force of the quadriceps of the left lower limb will be measured on a weight bench using a strain gauge to determine force during isometric contraction (at 90° knee flexion). The position of the patient will be standardized: arms crossed over the chest, no back support during the measurement and no support of the hips and contralateral leg to avoid any compensatory movement. Three reproducible measurements (+/-10%) will be taken at 1 min intervals, with the highest value selected.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
6-minute walk test
The 6-min walking test (6MWT) measures the distance that a patient can walk on an indoor 30-m flat corridor for a 6-min period. Due to a familiarisation effect, two tests will be performed, with at least 15 min of intervening rest, with the greatest distance in the two tests being recorded. The 6-min walking distance (6MWD) will be expressed in metres. Other variables will be measured: minimum pulse oxygen saturation (SpO2), peak heart rate and dyspnoea and fatigue ratings at the end of test.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
Quality of life questionnaires
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
Number of steps walked daily measured by actigraphy
Actigraphy is an objective measurement of physical activity using a device that measures acceleration and movement (accelerometer). The number of steps walked daily is used to assess free daily-living activity in clinical trials. It is measured using an accelerometer worn 24 hours a day during five days. In this study, we will use the triaxial accelerometer Actigraph GT3X®. Instructions for the medical device use are provided on the website https://www.theactigraph.com. The patient will be instructed to wear the accelerometer around the wrist 24 hours a day during 5 consecutive days including week-end and will be asked to maintain usual routine activity. The number of steps walked daily will be the average of the daily number of steps over the five days.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
Flow-mediated dilation
Flow-mediated dilatation (FMD) of the brachial artery will be calculated according to standard recommendations. Briefly, a pneumatic cuff will be placed on the right forearm distal to the elbow. The probe will be placed approximately midway between the antecubital and axillary regions and secured with a stereoscopic arm. Basal diameter and velocity will be recorded continuously for a minimum period of one minute. The cuff will then be inflated to 250 mm Hg for 5 minutes before sudden deflation to induce post-ischemic hyperemia. Fifteen minutes later, baseline measurements will be repeated to measure endothelial-independent, nitrate-induced dilatation. Nitrate-induced dilatation (NMD) will be calculated 4 min after sublingual administration of 0.3 mg trinitrin (NATISPRAY, Teofarma S.R.L. Italy). FMD and NMD will be expressed as a percentage change in basal diameter and in mm, after post-ischemic hyperemia and after administration of nitrate derivatives, respectively.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
BODE index
The BODE index is a multidimensional index of disease severity in COPD that incorporates four independent predictors: the body mass index (BMI), the degree of airflow obstruction assessed by the Forced Expiratory Volume in one second (FEV1), the modified Medical Research Council (mMRC) dyspnea scale, and the exercise capacity assessed by the 6-min walking distance (6MWD) test.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
COPD Assessment Test (CAT)
the COPD Assessment Test (CAT) is a patient-completed questionnaire assessing globally the impact of COPD (cough, sputum, dysnea, chest tighteness) on health status. CAT scores range from 0 to 40. Higher scores indicate a more severe impact of COPD on the patient's life. The difference between stable and exacerbating patients is five units. No target score represents the best possible outcome.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
Visual Simplified Respiratory Questionnaire (VSRQ)
The Visual Simplified Respiratory Questionnaire (VSRQ) is designed to assess health-related quality of life (HRQoL) in patients with chronic obstructive pulmonary disease (COPD). It contains eight items: dyspnea, anxiety, depressed mood, sleep, energy, daily activities, social activities and sexual life.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
mMRC dyspnea scale
the Modified Medical Research Council (mMRC) Dyspnea Scale Stratifies severity of dyspnea in respiratory diseases, particularly COPD. The higher the degree, the more severe the shortness of breath.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
DIsability RElated to COPD Tool (DIRECT)
The DIsability RElated to COPD Tool (DIRECT) is a 10-item questionnaire that specifically assesses COPD-related disability.
Time frame: baseline, 45+/-5 day and 1 year +/- 2 weeks
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