Disease progression and costs at two‐year follow‐up of GERAS‐US: A three‐year study of mild cognitive impairment and mild dementia due to Alzheimer’s disease in the United States

Abstract

AbstractBackgroundGERAS‐US is a 36‐month study that aims to understand long‐term clinical and economic outcomes of Alzheimer’s disease (AD). Changes in total costs at 1 and 2 years post‐baseline in beta‐amyloid‐positive [+] patients with mild cognitive impairment (MCI) and mild dementia (MILD) are reported.MethodsPatients aged 55 to 85 years (N=617) were enrolled from 30 October 2016 through 09 October 2017. Mean 30‐day total societal costs (direct and indirect using opportunity costs [Figure 1]) were captured. Opportunity cost sums lost productive hours multiplied by national average annual gross hourly wage for workers and by lost leisure time for nonworkers (35% of hourly wage for workers). Costs are presented as mean (95% confidence interval [CI]) at baseline and at 1 and 2 years for the overall population and stratified by baseline severity (MCI vs MILD). Mean (95% CI) changes from baseline at 1 and 2 years are presented. A repeated measures model was used. Comparisons were conducted at 5% significance level.ResultsAt baseline, patient mean age was 70.3 years for MCI and 71.7 years for MILD; overall, 52.7% were females. Analyses at 1 and 2 years post‐baseline included 483 (78.3%) and 388 (62.9%) patients, respectively. For amyloid[+] patients, mean change from baseline in Cognitive Function Index (study partner version) and Mini‐Mental State Examination scores demonstrated worsening at 1 and 2 years (Table 1). Mean estimated total societal costs for overall population decreased at 1 ($2343; p<0.001) and 2 years ($2641; p=0.026) vs baseline ($3033). Neither direct medical nor direct nonmedical costs changed over the 2‐year period for MILD patients, but direct medical costs increased significantly at Year 2 vs Year 1 for MCI patients (p=0.024; Table 2). Direct costs for study partners did not change over a 2‐year period; however, indirect costs were significantly higher for MILD vs MCI cohort at Years 1 and 2 (p£0.001).ConclusionsBoth function and cognition declined over 2‐year period for AD patients. In amyloid[+] MCI AD patients, direct medical costs increased from Year 1 to Year 2. Understanding why costs did not increase for MILD AD patients, despite clinical progression, requires further study.