In:
Alzheimer's & Dementia, Wiley, Vol. 16, No. S9 ( 2020-12)
Abstract:
Although often used as outcome measure in treatment studies, the clinical meaningfulness of scores on instrumental activities of daily living (IADL) questionnaires is not yet well‐established. We aimed to establish cut‐offs for clinically meaningful categories of IADL functioning, as determined by caregivers of dementia patients using the Amsterdam IADL Questionnaire (A‐IADL‐Q). Secondly, we examined category change within a 1‐year follow‐up period in memory clinic patients. Method First, we performed a qualitative study to determine four clinically meaningful categories on the A‐IADL‐Q: ‘no impairment’, ‘mild’, ‘moderate’, or ‘severe impairment’. T ‐scores ranged from 20–70, with lower scores representing more severe impairment. In focus groups, caregivers ( n =6) were invited to rate written scenarios representing various levels of IADL impairment (‘vignettes’). The vignettes were based on the most likely item responses at given total scores of the A‐IADL‐Q, to which caregivers were blinded. First, caregivers individually categorized the vignettes. Based on nominal group technique, they subsequently placed votes for a category on each vignette. Then, they engaged in group discussion to reach consensus about the categorization. From this, we derived cut‐offs on the A‐IADL‐Q T ‐score. Second, in a quantitative study, we applied the cut‐offs in a longitudinal sample of 169 patients (Table 1) from the Amsterdam Dementia Cohort, diagnosed with either subjective cognitive decline, mild cognitive impairment, Alzheimer’s disease dementia, and other dementias. We assessed what proportion of patients changed to worse categories. Result There was some discussion about the categorization, in particular for deciding which vignettes represented ‘moderate’ and ‘severe impairment’. Consensus cut‐offs were established for mild (≥57.5), moderate (≥47.5), and severe impairment (≥42.5). Figure 1 shows the proportion of patients in each category for the different diagnoses, at baseline and after 1 year. Within one year, 45 patients (26.6%) progressed to a worse clinical category. Conclusion This study provides cut‐off values for clinically meaningful categories, which seem to be in correspondence with disease severity. Over a relatively short follow‐up period of 1 year, approximately one quarter of patients declined to a worse category, providing support for the ability of the A‐IADL‐Q to measure clinically meaningful change.
Type of Medium:
Online Resource
ISSN:
1552-5260
,
1552-5279
Language:
English
Publisher:
Wiley
Publication Date:
2020
detail.hit.zdb_id:
2201940-6
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