Predicting progression of Alzheimer’s disease

There is considerable variability in progression rates among Alzheimer’s disease (AD) patients. Patients and families frequently ask clinicians to prognosticate regarding expected rates of cognitive and functional decline, and clinicians have little basis for making such predictions.

We have shown that it is possible to reliably estimate early AD symptom onset, and together with baseline MMSE score, to calculate a rate of progression at the initial assessment (the preprogression rate).

The use of a rate to estimate early progression gives information on severity, but also on how long it took for the patient to reach the current severity level, which reflects that individual’s disease characteristics better than a severity score alone. However, it is not clear whether patients maintain a similar rate of decline throughout the course of their disease or change trajectories over time, due to endogenous or exogenous factors (such as treatment).

Demonstrating the predictive value of the calculated pre-progression rate would be valuable for patient and family counseling, as well as for providing a research marker of phenotypic variability to validate biological markers of progression. Further, the ability to model group progression of AD patients is essential for designing disease-modification studies of new AD treatments, and pre-progression might be an important baseline variable to take into account in the analysis of clinical trial data

The Baylor Alzheimer’s Disease and Memory Disorders Center has followed a cohort of AD patients for up to 15 years, with detailed clinical and neuropsychological data obtained at baseline and at annual follow up visits which are maintained in an ongoing electronic data base.

We used these data to answer the following questions: 1) does a pre-progression rate calculated at the initial assessment predict subsequent performance in specific cognitive and functional domains during follow up, and 2) is the pre-progression rate associated with overall survival, after adjustment for relevant covariates?

This research study was published in BioMed Central's open access journal. Go here to read Predicting progression of Alzheimer's disease.

Rachelle S Doody, Valory Pavlik, Paul Massman, Susan D Rountree, Eveleen Darby, Wenyaw Chan