The aim of this study is to investigate the nutritional status of patients with chronic pulmonary disease undergoing regular outpatient pulmonary rehabilitation.

Background：

Exercise limitation due to impaired respiratory function is a common problem for COPD patients, and reduced muscle mass and malnutrition can exacerbate symptoms, impacting their functional ability and quality of life. Underweight COPD patients have an increased risk of mortality and acute exacerbations. Therefore, monitoring the body composition, nutritional status, and metabolic state of COPD patients and providing adequate nutritional support are crucial aspects of COPD management.Compared to healthy older adults, COPD patients require higher protein intake. Most studies have focused on analyzing body composition, respiratory and limb muscle strength, exercise performance, physical activity, lung function, emotional perception, and self-perceived scales, with limited assessment and exploration of calorie intake. Moreover, calorie intake estimation has mostly relied on formulas, lacking personalized and accurate assessment through indirect calorimetry.

Study Design：

This study is a single-center, prospective, randomized controlled trial.

Methods：

COPD patients who meet the inclusion criteria will be enrolled and randomly assigned to either the nutritional supplementation intervention group (experimental group) or the standard pulmonary rehabilitation group (control group). The experimental group will receive personalized dietary guidelines based on indirect calorimetry assessment by a nutritionist, while the control group will undergo routine pulmonary rehabilitation without dietary intervention. The study will follow up for a duration of 12 weeks, collecting data on cardiopulmonary physiological parameters, body composition, muscle strength, exercise performance, and indirect calorimetry assessment. Additionally, we will calculate the differences in recommended calorie intake between formula estimation and indirect calorimetry.

Effect：

We anticipate that indirect calorimetry will yield different results for calorie estimation compared to weight estimation and the Harris-Benedict equation. The nutritional supplementation intervention is expected to lead to improved changes in body composition, enhanced exercise performance and muscle strength, as well as better cardiopulmonary physiological parameters and self-perceived ratings.

Key words：

Chronic obstructive pulmonary disease, pulmonary rehabilitation, nutritional supplementation, indirect calorimetry

Inclusion Criteria:

• Age between 45 and 80 years
• A written informed consent
• Pre-COPD or COPD stages I-IV as per the 2023 GOLD guidelines
• Recieved pulmonary rehabilitation at least three months
• Unwilling to nutritional outpatient assessment

Exclusion Criteria:

• Diagnosed with neuromuscular diseases
• Emergency room visits or hospitalizations for exacerbation of respiratory disease within three months
• Inability to cooperate with cardiopulmonary exercise testing
• Significant malnutrition or low BMI