Table 1.

PICO criteria used for the inclusion of studies.

Criteria	Definition
Participants	Patients with a confirmed diagnosis of COPD, no evidence of recent exacerbation, enrolled on a pulmonary rehabilitation or other exercise training program
Intervention	Any nutritional supplement given during pulmonary rehabilitation
Comparator	Placebo, other nutritional supplement regime, no nutritional supplements
Outcome	Exercise function, body composition, peripheral muscle strength, respiratory muscle function and quality of life.
Study design	No restrictions

COPD: chronic obstructive pulmonary disease; PICO: P—population, patient, problem; I—intervention; C—control, comparison or comparator; O—outcome.