Methodological considerations in cost of illness studies on Alzheimer disease

Abstract

Cost-of-illness studies (COI) can identify and measure all the costs of a particular disease, including the direct, indirect and intangible dimensions. They are intended to provide estimates about the economic impact of costly disease. Alzheimer disease (AD) is a relevant example to review cost of illness studies because of its costliness.The aim of this study was to review relevant published cost studies of AD to analyze the method used and to identify which dimension had to be improved from a methodological perspective. First, we described the key points of cost study methodology. Secondly, cost studies relating to AD were systematically reviewed, focussing on an analysis of the different methods used. The methodological choices of the studies were analysed using an analytical grid which contains the main methodological items of COI studies. Seventeen articles were retained. Depending on the studies, annual total costs per patient vary from $2,935 to $52, 954. The methods, data sources, and estimated cost categories in each study varied widely. The review showed that cost studies adopted different approaches to estimate costs of AD, reflecting a lack of consensus on the methodology of cost studies. To increase its credibility, closer agreement among researchers on the methodological principles of cost studies would be desirable.

Epidemiological and Economic Burden of Alzheimer's Disease: A Systematic Literature Review of Data across Europe and the United States of America

“…This variability could be due to a lack of standardization of the studies or to differences in healthcare systems between countries. Inconsistencies in the methodology used to assess AD cost of illness was previously established by Costa et al [72] who found that methods, data sources, and estimated cost categories varied widely between studies. Finally, data presented in this review were collected from 2002 onwards and costs associated with costly techniques recently included in the NINCDS-ADRDA criteria [2], such as MRI, PET, or CSF assay, are not taken into account, thus, underestimating the current medical costs.…”

The cost of work-related stress to society: A systematic review.

“…The finalized form extracted information relating to the study's background methodology, population, costs and sub-costs; and also included a study quality assessment checklist used to assess and compare the utilized methodologies. The checklist is based upon the ten-item health economic quality checklist (Drummond et al, 2005), which has been adapted for use in COI studies (Molinier et al, 2008;Te Ao, 2014).This adapted quality checklist has been used by several previous systematic reviews of COI studies examining Alzheimer's disease (Costa et al, 2012), opiate dependence (Doran, 2008), prostate cancer (Molinier et al, 2008), and traumatic brain injury (Te Au, 2014).…”

Cost-of-illness studies of atrial fibrillation: methodological considerations

“…A sensitivity analysis was missing in most studies. Varying the assumptions, for example, the disease definition in database studies or the valuation of unit costs, would allow the users of these studies to assess the robustness of the results [11,57]. Likewise, ranges for the results, for example, in terms of confidence intervals could strengthen the studies' credibility.…”