Mortality across the Alzheimer’s disease clinical stages: An analysis using the U.S. National Alzheimer’s Coordinating Center Uniform Data Set

Abstract

AbstractBackgroundUnderstanding mortality risk across the Alzheimer’s disease (AD) clinical stages is essential for resource planning and estimating the value of disease modifying therapies (DMTs), which may slow progression. Such studies are lacking.MethodThe study used the Uniform Data Set of the National Alzheimer’s Coordinating Center (NACC) from September 1, 2005 to March 1, 2021 to assess mortality risk across the AD clinical stages. It included 12,414 participants aged ≥ 50 years, who contributed to the following stages: cognitively unimpaired (CU n = 11,458), incident prodromal AD (n = 937), and AD dementia (n = 745). AD etiology and stage were established based on clinical evaluation and cognitive, behavioral, and functional scores. Study centers report mortality for actively followed participants. Participants contributed observation time until all‐cause death, disease progression, discontinuation, loss to follow‐up, data cutoff or the last visit before a longer than 36‐month gap in visits or recorded scores.Hazard ratios for each AD stage versus CU were estimated using Cox proportional hazards models. Least absolute shrinkage and selection operator facilitated final predictor selection.ResultParticipants’ mean age (SD) at study entry was 71.0 years (SD 9.2) (34.9% males). Participants with incident mild, moderate, and severe AD had increased mortality risk relative to CU after controlling for age, sex, education, apolipoprotein E ε4 genotype status, BMI, and residence type. Relative all‐cause mortality risk by AD stage decreased with increasing age; the HRs (95% CI) for mortality at 65 years of age were 6.7 (2.7‐16.9), 14.8 (8.8‐24.8), and 30.1 (16.7‐56.8) for mild, moderate and severe AD respectively; at 80 years of age, the corresponding HR (95% CI) were 2.4 (1.7‐3.3), 3.1 (2.4‐3.9), and 6.6 (4.8‐9.1). Male sex (HR = 1.75, 95% CI 1.52‐2.04) and residing in an institution (vs. private residence; HR = 3.11, 95% CI 2.28‐4.25) significantly increased relative all‐cause mortality risk.ConclusionRelative all‐cause mortality risk increases with AD severity, and more so at younger ages. Despite data limitations, findings are significant as efforts to delay disease, for instance with DMTs, could not only improve patient and caregiver quality of life and reduce costs, but also extend the lives of patients with AD.NIA/NIH Grant U24 AG072122 funds the NACC database.