estimates prevalent costs (costs-of-illness) for the year 1994, reflecting the most current data available at the time of this research. The emphasis is on direct costs, although productivity loss estimates are reported where they exist.
Policymakers solicit and researchers undertake cost-of-illness studies to demonstrate the impact of an illness on society. As noted earlier, these studies place the burden of illness in the context of annual spending related to a specific cause. Consumers of this information then can more accurately assess the priority of a problem or the appropriateness of the level of spending. For example, the Senate Appropriations Committee recently requested that the National Institutes of Health compile a table of annual costs of illness for leading causes of mortality. The request specified that a column indicating the fiscal year research funding for each cause of death should be included in the table (NIH, 1995).
Annual spending may reflect a minor or a major proportion of the total expenditures related to an illness. In the early 1980s, for example, annual costs for HIV infection represented only a very small part of the costs eventually attributable to existing infection. In addition, the annual burden of an illness gives no indication of the effectiveness of dollars invested in alleviating it. Nonetheless, the annual figure gives an indication of the importance of the problem at a point in time. As a result, federal offices and congressional committees have demonstrated interest in clarifying the methodology for these studies, in conducting them, and in assembling their results (Rice et al., 1985).
There are numerous obstacles to accurately accounting for resource use associated with disease and to the assignment of dollar values to these resources. Some problems are specific to assessing the cost of STDs, while other problems apply equally to the assessment of cost of both STDs and other illnesses.
A basic problem in assessing the cost of STDs is the difficulty in establishing incidence and prevalence. Counts of cases are critical when estimates are based on an annual cost per case that is multiplied by the estimated total number of cases. Because the United States has no integrated and comprehensive medical data system, incidence of illnesses must be estimated. The reporting of many STDs is required, and therefore their incidence should be easier to ascertain than the incidence of nonreportable diseases. However, the government does not require the reporting of some important (particularly viral) STDs, and even reportable STDs are commonly underreported. The extent of underreporting is not well understood. Surveys completed over two decades ago demonstrated that private physicians reported only 25-50 percent of the gonorrhea cases they treated (IOM, 1985; Moran et al., 1995). Updated information on reporting is currently being