Predicting progression to Alzheimer’s disease dementia using cognitive measures: findings from the Essex Memory Clinic

Abstract

AbstractBackgroundTimely diagnosis of Alzheimer’s disease (AD) is important for patients, carers and healthcare systems. It is therefore imperative to identify measures with the greatest power to predict future AD dementia. In contrast to research settings, expensive biomarkers are not always available in memory clinics. It is therefore vital to identify predictive measures which can be used in ordinary clinical settings.MethodThis study utilized clinical assessment data from 328 patients assessed in the Essex Memory Clinic between 2002 and 2019. Only patients with a diagnosis of subjective cognitive decline (SCD) or mild cognitive impairment (MCI) at baseline and a minimum of two follow‐up visits were included in analyses. Lasso logistic regression (using AD at visit 3 as the outcome) and Lasso Cox proportional hazards models (using time to AD at visit 3 and beyond as outcome) were fitted in two stages. The first stage included baseline cognitive scores only, while the second stage also included change scores for these measures (derived by subtracting scores at baseline from those at the first follow‐up visit).ResultIn the first stage models, lower Mini‐Mental State Examination (MMSE) and Logical Memory Test (LMT) delayed recall scores, and longer Trail‐Making Test part A (TMT‐A) time were associated with greater odds (logistic regression) and hazards (Cox proportional hazards) of progression to AD. In addition, in the Cox model (only), lower baseline Cambridge Cognitive Examination‐Revised (CAMCOG‐R) score was associated with greater hazard of AD. In the second stage models, worsening CAMCOG‐R and LMT (delayed recall) scores were independently associated with both the odds/hazards of AD.ConclusionIn this memory clinic cohort, the cognitive scores most predictive of progression to AD were the delayed LMT, TMT‐A, CAMCOG‐R and MMSE. These results are in‐keeping with earlier work conducted in research cohorts. The inclusion of cognitive change scores over one year follow‐up improved predictive accuracy versus baseline scores alone.