Does study partner type impact the rate of Alzheimer's disease progression?

Most patients with Alzheimer's disease (AD) do not have a spouse. Despite this, the majority of AD research participants enroll with a spouse study partner. It remains unclear if differences between AD patients who do and do not have a spouse may bias study results. In this study, we examined whether AD patients with different study partner types (spouse versus adult child) demonstrate different rates of disease progression over two years on three outcome measures commonly used in AD research, including clinical trials. We used data from the National Alzheimer's Coordinating Center Uniform Data Set to examine disease progression in participants age 55-90 with probable AD dementia. We examined disease progression as measured by the Clinical Dementia Rating Scale-Sum of the Boxes score, the Mini Mental Status Examination, and the Functional Assessment Questionnaire. Analyses were performed on data for all available eligible participants from the NACC UDS and after performing a propensity-matching model to better account for inherent differences between the populations of interest. Propensity matching was successful only when models did not include age and gender. For both propensity-matched analyses and those of all available data, we did not observe any differences between the study partner populations for any outcome measure. These results suggest that if investigators can improve in recruiting AD patients with adult child caregivers to research, the implications to study results may be minimal.