After having 4 chest infections in a year, I asked my doctor if Stiglagliptin may be an underlying factor. After some research she agreed and took me off them She also sent me for a chest x-ray which came back clear, but with (in small print) possible early stages of COPD. This really shocked me as I have never smoked!! However my doctor said this wording is often put on the bottom of chest x-ray results and can be misleading. So I think if this happens, more extensive tests to get a proper diagnosis may be the best way forward.