Minimal clinically important decline in physical function over one year: EPOSA study by Siviero, P, Limongi, F, Gesmundo, A, Zambon, S, Cooper, C, Dennison, EM, Edwards, MH, Timmermans, EJ, Van Der Pas, S, Schaap, LA, Van Schoor, NM, Denkinger, MD, Herbolsheimer, F, Peter, R, Castell, MV, Otero, Á, Queipo, R, Pedersen, NL, Deeg, DJH, Maggi, S