Pediatric AIDS at Mount Sinai Medical Center 1988-89: a study of costs and social severity

Cost-of-illness studies : a review of current methods

The number of cost-of-illness (COI) studies has expanded considerably over time. One outcome of this growth is that the reported COI estimates are inconsistent across studies, thereby raising concerns over the validity of the estimates and methods. Several factors have been identified in the literature as reasons for the observed variation in COI estimates. To date, the variation in the methods used to calculate costs has not been examined in great detail even though the variations in methods are a major driver of variation in COI estimates. The objective of this review was to document the variation in the methodologies employed in COI studies and to highlight the benefits and limitations of these methods. The review of COI studies was implemented following a four-step procedure: (i) a structured literature search of MEDLINE, JSTOR and EconLit; (ii) a review of abstracts using pre-defined inclusion and exclusion criteria; (iii) a full-text review using pre-defined inclusion and exclusion criteria; and (iv) classification of articles according to the methods used to calculate costs. This review identified four COI estimation methods (Sum_All Medical, Sum_Diagnosis Specific, Matched Control and Regression) that were used in categorising articles. Also, six components of direct medical costs and five components of indirect/non-medical costs were identified and used in categorising articles.365 full-length articles were reflected in the current review following the structured literature search. The top five cost components were emergency room/inpatient hospital costs, outpatient physician costs, drug costs, productivity losses and laboratory costs. The dominant method, Sum_Diagnosis Specific, was a total costing approach that restricted the summation of medical expenditures to those related to a diagnosis of the disease of interest. There was considerable variation in the methods used within disease subcategories. In several disease subcategories (e.g. asthma, dementia, diabetes mellitus), all four estimation methods were represented, and in other cases (e.g. HIV/AIDS, obesity, stroke, urinary incontinence, schizophrenia), three of the four estimation methods were represented. There was also evidence to suggest that the strengths and weaknesses of each method were considered when applying a method to a specific illness. Comparisons and assessments of COI estimates should consider the method used to estimate costs both as an important source of variation in the reported COI estimates and as a marker of the reliability of the COI estimate.

The cost of HIV treatment and care. A global review

This review of published studies on the costs of HIV treatment and care describes some of the recent developments that have influenced these costs in industrialised and industrialising countries, especially within the context of changing drug treatments. Some of the different approaches to estimating the economic impact of HIV infection are briefly presented. The methods used to review the literature are described, particularly the criteria of a scoring system that was specifically developed to systematically screen some of the studies identified. The mean review score for studies dealing with direct hospital costs increased significantly (p = 0.003) over the 3 periods analysed (before 1987, 1987 to 1995, and 1996 and beyond), indicating that the overall 'quality' of studies increased over time. All cost estimates, other than those from non-industrialised regions, were converted to 1996 US dollars using country-specific total health expenditure inflaters and country-specific Gross Domestic Product Purchasing Power Parity converters. A summary of hospital cost estimates over time and by region demonstrated that the costs of treating asymptomatic individuals and people with symptomatic non-AIDS increased over the period, but that the costs of treating individuals with AIDS appears to have stabilised since the late 1980s. As fewer studies could be identified on the costs of community and informal care, indirect productivity costs and population cost estimates, and costs of care for children with HIV infection, all of these studies were reviewed without the use of the scoring system. Finally, the discussion explores the evidence on the global costs of HIV in non-industrialised economies and the affordability of HIV treatment and care. Some suggestions for the direction of future HIV costing studies are also presented. A need remains for good quality cost data. Adequate research effort should be directed to improving the scope and quality of information on costs of HIV service provision around the world.