Predicting conversion to dementia in a memory clinic: A standard clinical approach compared with an empirically defined clustering method (latent profile analysis) for mild cognitive impairment subtyping

Introduction: Mild cognitive impairment (MCI) has clinical value in its ability to predict later dementia. A better understanding of cognitive profiles can further help delineate who is most at risk of conversion to dementia. We aimed to (1) examine to what extent the usual MCI subtyping using core criteria corresponds to empirically defined clusters of patients (latent profile analysis [LPA] of continuous neuropsychological data) and (2) compare the two methods of subtyping memory clinic participants in their prediction of conversion to dementia.Methods: Memory clinic participants (MCI, n 5 139) and age-matched controls (n 5 98) wererecruited. Participants had a full cognitive assessment, and results were grouped (1) according totraditional MCI subtypes and (2) using LPA. MCI participants were followed over approximately2 years after their initial assessment to monitor for conversion to dementia.Results: Groups were well matched for age and education. Controls performed significantly betterthan MCI participants on all cognitive measures.With the traditional analysis, most MCI participantswere in the amnestic multidomain subgroup (46.8%) and this group was most at risk of conversion todementia (63%). From the LPA, a three-profile solution fit the data best. Profile 3 was the largestgroup (40.3%), the most cognitively impaired, and most at risk of conversion to dementia (68% ofthe group).Discussion: LPA provides a useful adjunct in delineating MCI participants most at risk of conversionto dementia and adds confidence to standard categories of clinical inference.