Disease progression and costs at 3‐year follow‐up of GERAS‐US: A 3‐year study of mild cognitive impairment and mild dementia due to Alzheimer’s disease in the United States

Abstract

AbstractBackgroundGERAS‐US is a prospective study characterizing the clinical and economic outcomes of early Alzheimer’s Disease (AD). We describe changes in total societal costs at 3 years post‐baseline in amyloid positive[+] patients with mild cognitive impairment (MCI) and mild dementia (MILD) due to AD.MethodGERAS‐US enrolled patients aged 55 to 85 (N=617) from October 30, 2016, through October 9, 2017. Cognition and function were assessed using Mini Mental State Exam (MMSE) and Cognitive Function Index (CFI), respectively. Mean 30‐day total societal costs (direct and indirect costs using opportunity formulae [Figure 1]) were calculated. Costs are presented as least square (LS) mean (95% confidence interval [CI]) at baseline, 6 months and 36 months for the overall population and stratified by baseline severity (MCI[+] vs MILD[+]) using Mixed Model Repeated Measurement (MMRM). Least square mean (95% CI) changes from 6 months to 36 months, using MMRM, are presented.ResultAt baseline, mean age was 70.3 years (MCI) and 71.7 years (MILD); 52.7% were females. Analyses at 36 months post‐baseline included 308 patients. Mean change from baseline in CFI and MMSE scores demonstrated worsening over 36 months (Table 1). The LS mean estimated total societal costs for MCI and MILD, respectively, were higher at baseline ($2430 and $4063) but remained steady from 6 months ($1977 and $3032) to 36 months ($2007 and $3392) (Figure 2). Direct medical costs did not change over the follow‐up period (6 months to 36 months) for either MILD or MCI patients or for their caregivers. Direct nonmedical costs were significantly higher for MILD but not MCI patients. Indirect nonmedical caregiver costs trended higher for both MCI and MILD cohorts but were not significant (Table 2).ConclusionBoth function and cognition declined significantly over 36 months in this cohort of amyloid[+] patients. Direct medical costs remained steady over the follow‐up period after an initial decline from baseline, possibly due to diagnostic certainty achieved at baseline. The rise in direct nonmedical costs for MILD and the trend toward rising indirect caregiver costs in MCI and MILD patients over 36 months shows the additional economic impact associated with clinical progression in early AD.