Resource utilisation, costs and clinical outcomes in non-institutionalised patients with Alzheimer's disease: 18-month UK results from the GERAS observational study

Abstract

Background: Alzheimer's disease (AD), the commonest cause of dementia, represents a significant cost to UK society. This analysis describes resource utilisation, costs and clinical outcomes in non-institutionalised patients with AD in the UK. Methods: The GERAS prospective observational study assessed societal costs associated with AD for patients and caregivers over 18 months, stratified according to baseline disease severity (mild, moderate, or moderately severe/severe [MS/S]). All patients enrolled had an informal caregiver willing to participate in the study. Healthcare resource utilisation was measured using the Resource Utilization in Dementia instrument, and 18-month costs estimated by applying unit costs of services and products (2010 values). Total societal costs were calculated using an opportunity cost approach. Results: Overall, 526 patients (200 mild, 180 moderate and 146 MS/S at baseline) were recruited from 24 UK centres. Mini-Mental State Examination (MMSE) scores deteriorated most markedly in the MS/S patient group, with declines of 3.6 points in the mild group, 3.5 points in the moderate group and 4.7 points in the MS/S group; between-group differences did not reach statistical significance. Patients with MS/S AD dementia at baseline were more likely to be institutionalised (Kaplan-Meier probability 28% versus 9% in patients with mild AD dementia; p < 0.001 for difference across all severities) and had a greater probability of death (Kaplan-Meier probability 15% versus 5%; p = 0.013) at 18 months. Greater disease severity at baseline was also associated with concomitant increases in caregiver time and mean total societal costs. Total societal costs of £43,560 over 18 months were estimated for the MS/S group, versus £25,865 for the mild group and £30,905 for the moderate group (p < 0.001). Of these costs, over 50% were related to informal caregiver costs at each AD dementia severity level. Conclusions: This study demonstrated a mean deterioration in MMSE score over 18 months in patients with AD. It also showed that AD is a costly disease, with costs increasing with disease severity, even when managed in the community: informal caregiver costs represented the main contributor to societal costs.