PRM28 - What are indirect costs in neurodegenerative diseases? a methodological review

Abstract

Neurodegenerative diseases (NDs) refer to a group of diseases that affect brain cells. Alzheimer disease (AD), Parkinson disease (PD), Amyotrophique Lateral Sclerosis (ALS) and Multiple Sclerosis (MS) are the most prevalent NDs. NDs cause a substantial economic burden worldwide and indirect costs are an important component of total costs. This study aims to review relevant papers to characterize the different components of indirect costs and to identify the weight of indirect costs on total costs in different NDs. A systematic bibliographic search was performed on an international medical literature database (MEDLINE). All studies which assessed the social economic burden and indirect costs of different NDs were selected. Indirect costs were characterized into several types (i.e. sick leave, presenteeism, early retirement, premature death, reduction in working hours, informal care time) and into several valuation (i.e. Human Capital Approach, Friction Cost Method, Willingness To Pay). 44 studies met our criteria. Depending on studies, the percentage of indirect costs on total costs varies from 1% to 68% in PD, from 2% to 89% in AD, from 24% to 59% in ALS and from 29% to 78% in MS. The main indirect costs component was early retirement in PD, ALS and MS. This component varies from 61% to 95% of indirect costs in PD, from 35% to 88% in ALS and from 61% to 95% in MS. The main indirect costs component in AD was informal care time and account for almost 100% of indirect costs. Indirect costs increase with severity level in AD and MS, and decrease with severity level in ALS. Components of indirect costs are different depending on studies and especially for AD where indirect costs mainly refer to informal costs which should be considered as a full cost category to avoid the lack of understanding.