Effect of regular use of high-dose nebulized β2-agonists on resting energy expenditure, weight, and handgrip strength in patients with chronic airflow limitation

Study objectives: A proportion of patients with chronic airflow limitation (CAL) have a raised resting energy expenditure (REE). The mechanism underlying this is not known. The question of whether the increased REE seen in some patients with CAL is due to beta(2)-agonist therapy has arisen, and the aim of this study was to examine REE, body composition, and peripheral muscle strength in patients before and after the use of regular high-dose beta(2)-agonists administered by nebulizer. Design: Prospective observational study. Setting: Respiratory outpatient clinic. Participants: Twenty outpatients with CAL being considered for a home nebulizer prescription. Interventions: REE was measured by indirect calorimetry. Fat-free mass and handgrip strength were measured. Quality of life was assessed by the St. George's Hospital Respiratory Questionnaire. All subjects were assessed independently of this study for provision of a home nebulizer using a standard protocol. Based on the assessment, either standard-dose salbutamol therapy was continued or a nebulizer was provided with a prescription for high-dose salbutamol (5 mg qd). A mean of 8.1 months later (range, 3 to 16 months), 16 patients were restudied. Measurements and results: Eight patients had been taking regular high-close nebulized salbutamol, and eight had continued taking standard-dose salbutamol by metered dose inhaler. There was no difference in baseline measures between the group who were later prescribed high-dose salbutamol and the group who were not. There were no changes in REE, anthropometric measures, or handgrip strength over time in either of the groups. Conclusions: The long-term use of high-dose nebulized beta(2)-agonists in patients with chronic airflow limitation has no effect on baseline REE, handgrip strength, weight, or body composition.