Clinical characteristics, risk factors, and outcomes of POEMS syndrome: a longitudinal cohort study by Keddie, S, Foldes, D, Caimari, F, Baldeweg, SE, Bomsztyk, J, Ziff, OJ, Fehmi, J, Cerner, A, Jaunmuktane, Z, Brandner, S, Yong, K, Manji, H, Carr, A, Rinaldi, S, Reilly, MM, D'Sa, S, Lunn, MP