HOW FAR VS HOW FAST IN ALZHEIMERS-DISEASE - THE QUESTION REVISITED

Objective: To expand on a recent study of 42 patients with probable Al zheimer's Disease that found that the only significant predictors of c ertain clinical end points were the degree of severity features at ent ry (''how far''). Design: A case series study of a cohort of 81 patien ts with Alzheimer's disease that used survival analysis methods simila r those of the previous study but included a new technique for calcula ting rate of progression (''how fast'') as well as entry characteristi cs (''how far''). Setting: A university medical center and its affilia ted Veterans Affairs Medical Center. Patients: All patients with proba ble and definite Alzheimer's disease studied at the Aging Clinical Res earch Center at Stanford University, Pale Alto, Calif, in the years 19 81 and 1992 who met the following criteria: a mild to moderate level o f severity of the disease (Mini-Mental State Examination score of 15 o r above) at entry into the study and a minimum of three test points sp aced approximately 6 months apart (to allow estimation of rate of prog ression). A total of 81 such patients were identified. These patients had been followed up for a mean of 4.53+/-2.3 years, with a range of 1 .0 to 14.5 years. Main Outcome Measure: The outcome measure was the av erage rate of decline on the Mini-Mental State Examination. Results: T he results of our study replicated a previous finding that the degree of severity is a strong predictor of time course, but in addition we f ound that the rate of progression also appears to be a strong predicto r of clinical course. Conclusion: There appears to be substantial hete rogeneity in the rate of progression in patients with Alzheimer's dise ase, and, like initial degree of severity, rate of progression appears to be a strong predictor of clinical course.