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Problems found with estimates of infection, deaths
The proposed 1997 tuberculosis (TB) stand-ard by the Occupational Safety and Health Administration (OSHA) would impose requirements that afford little additional protection in low-risk areas while adding significant costs and administrative burdens on health care facilities, an Institute of Medicine (IOM) panel has concluded.
The report, though not offering specific recommendations regarding the fate of the standard, would appear to further undercut OSHA’s attempt to finalize the rule.
For one thing, the IOM panel found that OSHA’s 1997 estimates overstated the number of infections, cases of disease, and deaths due to TB that would be averted by adoption of the rule. TB case rates are down substantially from 1994 and the earlier years used for the estimates, and implementation of community and workplace TB control measures appears to be considerably improved, the panel noted.
"Recent data on tuberculosis infection are limited but indicate low levels of tuberculosis infection in health care facilities and suggest that exposure in the community is a significant factor in health care worker infections," the report states. "In addition, the agency’s estimates relied on assumptions about the progression of tuberculosis from infection to active disease and from disease to death that are widely used but inconsistent with available data and are unlikely to fit employed workers with reasonably good access to health care."
Controversial from the onset, the OSHA standard was proposed after a national resurgence of TB that included several nosocomial outbreaks. But even as the standard was proposed, many epidemiologists and infection control professionals argued that TB was already in rapid decline because of public health measures that included 1994 guidelines for health care settings by the Centers for Disease Control and Prevention.
In November 1999, the U.S. Congress requested the IOM study to examine the risk of TB among health care workers and the possible effects of federal guidelines and regulations intended to protect workers. (See questions and answers, pp. 23-24.)
"We tried to identify conditions that a rule would need to meet to be effective, and we concluded that it was likely to meet the first condition, which was that it be based on measures that were effective in reducing transmission of TB," says Marilyn Field, PhD, chief program officer with the IOM in Washington, DC. Similarly, the committee also determined the OSHA rule could meet the second condition, meaning that it would likely sustain and increase the level of adherence to TB control measures.
"[The third condition was] that it needed to allow reasonable flexibility to adapt measures to fit differences in the level of risk facing workers," Field says. "That is what our concern was: that, overall, if the final standard followed the 1997 rule, that it might not provide sufficient flexibility."
For example, as an indicator of TB risk in the community, the proposed rule would require use of county-level data to assess community risk, even though a facility’s service area might be quite different and have a much different incidence of TB. County lines and medical service areas do not always correspond, Field noted, adding that even if a facility referred TB cases elsewhere, it could still fall under OSHA provisions if there was at least one case of TB annually in its county for the previous two years.
"The committee felt that this categorization was too inflexible and noted that the CDC guidelines provided for more risk categories and took more information into account in establishing those categories," she says. "The CDC approach also described community data rather than county data."
The IOM panel also was aware that the CDC is in the process of changing its TB skin-test provisions, primarily because too many health care workers are testing false positive in low-prevalence areas. (See HIC, April 2000, pp. 45-48, under the archives at www.HIConline.com.)
"[There was] concern about locking in more excessive testing for these low prevalence areas and the resulting likely problem of false positives and unnecessary treatment," she says.
The IOM also raised another possible area of inflexibility, noting that the proposed OSHA rule also would require respiratory protection programs for workers who may have little risk of exposure. "[There was] concern that the respiratory protection requirements may not be sufficiently flexible to fit the risk facing workers," Field says.
(Editor’s note: The full IOM report has been posted on your subscriber Web site www.HIConline.com under "Headline Watch." A follow-up story with more analysis of the IOM report — and its likely impact on the OSHA standard — also has been posted on the Web site under "Headline Watch.")