Do instrumental activities of daily living predict dementia at 1- and 2-year follow-up? Findings from the Development of Screening guidelines and diagnostic Criteria for Predementia Alzheimer's disease study.

OBJECTIVES

To investigate whether problems in instrumental activities of daily living (IADL) can add to conventionally used clinical measurements in helping to predict a diagnosis of dementia at 1- and 2-year follow-up.

DESIGN

Multicenter prospective cohort study.

SETTING

Memory clinics in Europe.

PARTICIPANTS

Individuals aged 55 and older without dementia.

MEASUREMENTS

IADLs were measured using pooled activities from five informant-based questionnaires. Structural equation modeling (SEM) was used to investigate the relation between IADLs and dementia. Age, sex, education, depression, and cognitive measures (Mini-Mental State Examination and verbal memory) were included in the model.

RESULTS

Five hundred thirty-one participants had baseline and 1-year follow-up assessments; 69 (13.0%) of these had developed dementia at 1-year follow-up. At 2-year follow-up, 481 participants were seen, of whom 100 (20.8%) had developed dementia. Participants with IADL disabilities at baseline had a higher conversion rate (24.4%) than participants without IADL disabilities (16.7%) (chi-square = 4.28, degrees of freedom = 1, P = .04). SEM showed that IADL disability could help predict dementia in addition to the measured variables at 1-year follow-up (odds ratio (OR) = 2.20, 95% confidence interval (CI) = 1.51-3.13) and 2-year follow-up (OR = 2.11, 95% CI = 1.33-3.33).

CONCLUSION

IADL disability is a useful addition to the diagnostic process in a memory clinic setting, indicating who is at higher risk of developing dementia at 1- and 2-year follow-up.