Secondary outcome measures include delirium severity and duration assessed with the Delirium Rating Scale Revised 98 ; number of delirium-free days ; adverse events ; hospital length-of-stay ; all-cause mortality ; new institutionalisation ; ( Instrumental ) Activities of Daily Living assessed with the Katz Index of ADL , and Lawton IADL scale ; cognitive function assessed with the Six-item Cognitive Impairment Test , and the Dutch short form Informant Questionnaire on Cognitive Decline in the Elderly .