title: "Can health status questionnaires be used as a measure of physical activity in COPD patients?" Heleen Demeyer, Ivan Dueñas-Espín, Corina De Jong, Zafeiris Louvaris, Miek Hornikx, Elena Gimeno-Santos, Matthias Loeckx, Ioannis Vogiatzis, Wim Janssens, Nicholas S. Hopkinson, Roberto A. Rabinovich, Niklas Karlsson, Judith Garcia-Aymerich and Thierry Troosters, on behalf of the PROactive consortium.Eur Respir J2016; 47: 1565-1568.