Tuberculosis and Drug Resistance a Rising Threat
Gebhart, Fred, Drug Topics
Don't ignore the screaming headlines about a national tuberculosis epidemic. They appear be true.
"We're in an epidemic situation," confirmed Sarah Royce, chief of the TB control unit for California's Department of Health Services. After years of annual 5% decreases in new infection reports, new cases jumped by more than 40% between 1985 and 1990.
The news is even worse at the national level. From 1953--when standardized national statistics first became available--through 1984, tuberculosis cases declined 5% to 6% annually, reported Dan Kopanoff, associate director of the TB elimination division of the Centers for Disease Control. In 1990 the new infection rate was up 9.4%. Figures for 1991 aren't yet available.
There's little question that TB is out of control in parts of the country," said Kopanoff. "It's epidemic in New York. In children, it's even more frightening: Childhood cases have increased by almost 41% since 1988."
There's more bad news to come. Historically, fewer than 5% of TB cases exhibit resistance to isoniazid and/or rifampin, the drugs of choice. The problem was so rare that CDC doesn't even ask state health departments about drug-resistant TB cases.
That's about to change. "Once resistant cases started," Kopanoff explained, "they started cropping up all over the place. We just don't know how bad it's gotten yet." Most confirmed reports of multi-drug resistance have come from Florida and New York, but there have been reports from at least 11 other states. In New York City, as many as 40% of new cases involve multi-drug resistance.
CDC will begin requiring drug resistance reports later this year, Kopanoff noted. He expects an advisory to test all new TB cases for drug susceptibility to become mandatory by May. He knows at least one case, he said, in which drug susceptibility test results didn't come back until the patient had already died.
Susceptibility testing is only the first step. Treating a multidrug-resistant TB costs 10 to 15 times more than managing a drug-susceptible case--if the pharmacist is able to obtain the second-line meds.
Streptomycin and PAS (paraaminosalicylic acid) are not currently available from U.S. manufacturers. The Food & Drug Administration hopes to find domestic manufacturers by the fall, said Kopanoff, but until that time, both of these drugs will remain in short supply.
FDA has granted CDC an Investigational New Drug waiver to import limited quantities of both drugs from Canada and distribute them nationwide on an "as needed" basis. Medication, hospital, and associated costs for multi-drug-resistant cases can cost upward of $200,000.
Infection statistics suggest that HIV patients are most at risk for tuberculosis, especially among Black and Hispanic IV drug users. In a 1989-90 survey, 3.4% of TB patients nationwide were co-infected with HIV. In New York City, 46.3% of TB patients also had HIV infection. The co-infection rates were 33.6% in Newark, 26.6% in Boston, 23.5% in Miami, 4% in Los Angeles, and 1.4% in San Francisco.
In healthy populations, fewer than 10% of TB infections progress to active disease, even without medication. …