Performance of the Eight-item Informant Interview to Differentiate Aging and Dementia within a context similar to the Swedish primary healthcare sector: a systematic review of diagnostic test accuracy studies.

Objective: Dementia is a common but underdiagnosed health problem. Instruments developed for initial screening exist internationally but are not available within the Swedish primary healthcare sector. This systematic review aimed to evaluate the diagnostic test accuracy of the Eight-item Informant Interview to Differentiate Aging and Dementia in identifying symptomatic dementia within a context similar to the Swedish primary healthcare sector.

Design: A systematic search was conducted in PubMed, CINAHL, PsycInfo, Cochrane Library and manually reference lists up to November 2019. Eligibility criteria were the reporting of Diagnostic test accuracy outcomes for the Eight-item Informant Interview to Differentiate Aging and Dementia's ability to identify dementia according to internationally approved criteria. The population of interest was selected within the community or primary care. QUADAS-2 was used for quality assessment, and data were analysed with a narrative approach.

Results: Five studies with a total of 13,345 participants were included. With sensitivity (88-100%), specificity (67-91%), positive and negative predictive values (28-63%; 96-100%) respectively, the results show that the Eight-item Informant Interview to Differentiate Aging and Dementia has good ability to identify true positives, false negatives and predict low-risk dementia. That is, the Eight-item Informant Interview to Differentiate Aging and Dementia has a greater ability to predict people who are at risk of not having dementia than to correctly identify those at risk of having dementia within the target population.

Conclusion: The results show that the Eight-item Informant Interview to Differentiate Aging and Dementia has the ability to identify persons with symptomatic dementia within the target population. Thus, an evaluation of its potential benefits should be considered and evaluated within the Swedish primary healthcare context. KEY POINTS Dementia is a common but underdiagnosed health problem. Instruments developed for initial screening exist but are not available within the Swedish primary healthcare sector. We found that the Eight-item Informant Interview to Differentiate Aging and Dementia (AD8), has the ability to identify individuals with symptomatic dementia within the target population. The Eight-item Informant Interview to Differentiate Aging and Dementia (AD8), has the potential to increase the possibility for timely detection of individuals with symptomatic dementia.