Effects of ghrelin treatment on exertional dyspnea in COPD: an exploratory analysis

A substudy of ghrelin treatment in a multicenter trial previously revealed that administration of ghrelin improves the exercise capacity of underweight COPD patients. To clarify exertional dyspnea more precisely, exploratory analysis was conducted on data from the substudy. Of 20 underweight COPD patients who were randomized to pulmonary rehabilitation with intravenous ghrelin (2 μg/kg, n = 10) or placebo (n = 10) twice daily for 3 weeks in the substudy, 16 (ghrelin = 9, placebo = 7) could be investigated for dyspnea break-point on the dyspnea-ratio (%) of Δoxygen uptake (\({\dot{V}}_{{\rm O}_{2}}\)) (= peak minus resting \({\dot{V}}_{{\rm O}_{2}}\)) curve. A significant treatment effect of ghrelin on percentage \({\dot{V}}_{{\rm O}_{2}}\) at the dyspnea break-point to Δ\({\dot{V}}_{{\rm O}_{2}}\) (p = 0.049) was achieved. In conclusion, underweight COPD patients benefitted from ghrelin treatment in terms of shifts to the early exercise phase of the dyspnea break-point during a standardized exercise program.