Emphysema: Physiologic Effects of Nutritional Support

BACKGROUND: Chronic obstructive pulmonary disease is a major health problem and a leading cause for hospital admission in the United States. A severe form of chronic obstructive pulmonary disease that is accompanied by weight loss is commonly referred to as pulmonary cachexia. Studies in the 1960s demonstrated associations in chronic obstructive pulmonary disease patients between weight loss, low FEV1, and early mortality. This observation was strengthened by a retrospective analysis of the Intermittent Positive Pressure Breathing Trial data that suggested malnutrition was an independent predictor of outcome in men with chronic obstructive pulmonary disease. The underlying basis relating malnutrition to adverse outcome in chronic obstructive pulmonary disease was unknown, although there was a large body of information indicating that pulmonary cachexia was associated with respiratory muscle atrophy, myofibrillar substrate depletion, and impaired skeletal and respiratory muscle function. The primary question was whether the nutrition-related functional deficits observed in underweight patients could be reversed. The first three years of the study supported a pilot project of oral nutrition therapy in malnourished chronic obstructive pulmonary disease patients. DESIGN NARRATIVE: All subjects underwent intubation during the initial testing interval and subsequently underwent dietary counseling and oral nutritional supplement during a two-month stabilization phase. Subjects who demonstrated adequate weight gain defined as achievement of more than 90 percent of ideal body weight or who were unable to tolerate intubation were eliminated from further investigation. Eligible subjects were randomized to either ENS or to dietary counseling only. Subjects randomized to ENS received enteral supplementation with Osmolite delivered by continuous infusion pump. Feedings were continuous or nocturnal for sixteen weeks in order to deliver a caloric intake of 1.7 times the resting energy value. Following the intervention phase, all subjects were maintained on dietary counseling on a monthly basis with oral nutritional supplements. Outcome variables were measured before and after the stabilization phase, at eight and sixteen weeks during the intervention phase, and at eight and sixteen weeks during the post-intervention phase. The primary outcome variable was muscle strength and its effect on exercise performance, dyspnea, and quality of life. Secondary outcome variables included morbidity and mortality. The grant was extended through November 1995 for data analysis. The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.