The Third Epidemic—Multidrug-Resistant Tuberculosis: Methods
The reported incidence of tuberculosis (ТВ) declined for decades in the United States reaching a nadir of 22,255 cases in 1984, but then leveled off and began to rise. During the period from 1985 to 1991, approximately 39,000 excess cases occurred over and above the expected number. This alarming reversal of the downward trend in incidence of ТВ is primarily attributed to AIDS and secondly, worsening urban economic and social conditions. An economic downturn has led to an increase in homelessness, and budget reductions or even elimination of public health programs involved with ТВ control have exacerbated the problem. In addition to the above factors, changes in immigration patterns have led to an influx of immigrants from countries with endemic ТВ (ie, Mexico, Haiti, Vietnam, China).
Several cities within the United States have been hit especially hard by this increase in the incidence of ТВ. In New York City, case rates have been rising since 1979 with 3,673 new cases in 1991 and a case rate of 50.2/100,000 population. This incidence of new cases represents a 143 percent increase over the incidence in 1980. According to the New York City Department of Health, the case rate is the highest in two decades and is five times the national rate. In fact, in 1991, New York City alone accounted for 14 percent of the nation’s 26,283 reported cases of ТВ. canadian neighbor pharmacy
The changing human immunodeficiency virus (HIV) epidemic has recently shown increases among intravenous drug users (IVDUs), minorities, and those with multiple sexual partners. More recently, an epidemic of multidrug-resistant tuberculosis (MDR-TB) has appeared in New York City and several other cities. In 1991, New York City reported 366 patients whose isolates were resistant to both isoniazid and rifampin. During the period of 1991-1992, 82 cases of MDR-TB were identified in three outbreaks in New York City.’ Of these, at least 85 percent were HIV-seropositive. The aforementioned dramatic increase in MDR-TB as well as a striking increase in patients with MDR-TB at Bellevue Hospital Center stimulated our interest in evaluating the clinical parameters of infected patients. We have referred to HIV and AIDS as the first epidemic, the resurgence of ТВ as the second epidemic, and the complicating drug-resistance problem in our ТВ patients as the third epidemic. To more fully characterize the third epidemic, we evaluated drug sensitivities over the past two decades and studied the medical histories of the most recent 100 patients with drug-resistant ТВ (DR-TB).
Bellevue Hospital Center is a large 1,232-bed municipal hospital in the lower east side of Manhattan that serves a population largely comprised of minorities (78 percent), an economically depressed urban sector, and prisoners. The Mycobacteriology Laboratory at Bellevue processes approximately 25,000 specimens per year. Of these specimens, approximately 300 to 500 per year represent cases new to Bellevue with positive sputum cultures for Mycobacterium tuberculosis. We analyzed the drug susceptibilities of the first isolate recovered from 4,681 such cases of ТВ from 1971 to 1991 at Bellevue Hospital.
From Jan 1, 1991, to July 1, 1991, there were 224 patients at Bellevue with a positive culture for M tuberculosis, 74 of which were resistant to one or more of the following: isoniazid, rifampin, ethambutol, or streptomycin. We evaluated these 74 patients plus an additional 26 (n = 100, DR-ТВ) from Oct 1,1990, to July 31,1991, and compared them with 54 randomly selected drug-sensitive ТВ (DS-TB) cases. We abstracted demographic and clinical data from medical charts and evaluated the posteroanterior chest x-ray films. Homelessness was defined as “person(s) who do not have customary and regular access to a conventional dwelling or resi-dence.” Weight loss was defined as a loss of more than ten pounds over the previous two months. The Student’s t test (unpaired) was used for statistical comparisons.