Giving meaning to the scores of the Amsterdam instrumental activities of daily living questionnaire: a qualitative study

BACKGROUND: Everyday functioning is a clinically relevant concept in dementia, yet little is known about the clinical meaningfulness of scores on functional outcome measures. We aimed to establish clinically meaningful scoring categories for the Amsterdam Instrumental Activities of Daily Living Questionnaire (A-IADL-Q), representing no, mild, moderate and severe problems in daily functioning. METHODS: Informal caregivers (n = 6) of memory-clinic patients and clinicians (n = 13), including neurologists and nurse specialists, working at various memory clinics in The Netherlands. In focus groups, participants individually ranked nine summaries of fictional patients from least to most impairment in daily functioning. Then, they placed bookmarks to demarcate the thresholds for mild, moderate and severe problems. Individual bookmark placements were then discussed to reach consensus. Clinicians completed a survey in which they placed bookmarks, individually. RESULTS: While individual categorizations varied somewhat, caregivers and clinicians generally agreed on the thresholds, particularly about the distinction between 'no' and 'mild' problems. Score categories were no problems (T-score ≥ 60), mild problems (T-score 50-59), moderate problems (T-score 40-49), and severe problems in daily functioning (T-score < 40), on a scale ranging 20-80. CONCLUSIONS: Our findings provide categories for determining the level of functional impairment, which can facilitate interpretation of A-IADL-Q scores. These categories can subsequently be used by clinicians to improve communication with patients and caregivers.