OBJECTIVES: Age is the most critical risk factor for Alzheimers Disease (AD). Females are more likely to be diagnosed with the disease than males. It is unclear if this difference in risk translates to differences in disease progression. This study aimed to estimate the probabilities of transition between stages of severity (mild, moderate, severe, and death) in AD.

METHODS: We sampled 9,365 patients aged 65 years or older with a diagnosis of AD from the National Alzheimer’s Coordinating Center (ACC) longitudinal database. All selected patients had more than one annual visits to the Alzheimer’s Disease Centers between 2005-2015. We developed a multistate model using msm package in R to calculate annual transition probabilities by age group and gender. Age groups examined were: 65-74, 75-84 and 85 or older years.

RESULTS:The annual probabilities of death in patients aged 65-74 years with mild, moderate, and severe AD were higher in males (0.8%, 10.0%, and 31.8%) compared with females (0.4%, 4.2%, and 20.4%). The trend was similar in patients 75-84 years of age with mild, moderate and severe AD (Males: 1.7%, 12.2%, and 31.9%; Females: 0.9%, 6.0%, and 20.7%) and those aged 85 years or older (Males: 5.5%, 15.7%, and 39.6%; Females: 4.2%, 13.5%, and 28.4%). The annual probabilities of moving to severe AD in male patients aged 65-74 years with mild or moderate AD were 2.2% and 29.6%, respectively. In females, they were 1.9% and 29.4%. Results for patients aged 75-84 and 85 years or older followed a trend similar to that seen in patients aged 65-74 years.

CONCLUSIONS: Transitions for AD across stages of severity were slightly higher in males than females and older patients than younger ones. These probabilities can be used to evaluate age and gender-specific cost-effectiveness of new treatments in state-transition models.