The association of circulating GDF‐15 levels with muscle mass is not unique to COPD as GDF‐15 has been associated with cancer cachexia36 in a number of studies, and we have shown that patients who show wasting of the rectus femoris following cardiac surgery are exposed to a more sustained elevation of GDF‐15 than those who do not waste.11 Furthermore, the link between GDF‐15 and all‐cause mortality may reflect the effects of this growth factor on muscle homeostasis. The gene discussed is GDF15; the disease is chronic obstructive pulmonary disease.