Fewer cases, but sicker? Data suggest it’s true
More morbidity may accompany other shifts
As the proportion of TB patients who are foreign-born increases, patients may be getting sicker, says Kim Fields, RN, head of TB control for Washington state. "Even though our TB cases are down, we’re seeing a shift toward more cases among the foreign born," she says. "And with that shift, we’re also seeing a shift toward more difficult cases."
The sense is widespread among clinicians that TB in foreign-born patients is often accompanied by more morbidity and is harder to diagnose and treat, says Fields. But evidence to support that theory was scant until Fields and Charles Nolan, MD, the TB control officer for Seattle/King County, analyzed a five-year span of data from the state.
Looking at case data from 1995 to 1999, the two found increased morbidity concentrated among foreign-born patients almost across the spectrum — more infectiousness, more drug resistance, and more instances of an especially tricky kind of extrapulmonary TB, says Fields.
In a jurisdiction such as King County, where expertise and cultural sensitivity are abundant, the public health system has the capacity to absorb such changes, but in remote rural areas, that may not be the case, she says.
Few cases hit small jurisdictions hard
In 1999, for example, the state documented four instances of multidrug-resistant TB. All four cases occurred among foreign-born patients. One of them was resistant to five drugs, and another to seven.
"Three of the cases were in counties that hadn’t seen TB in 10 or 20 years," says Fields. Treating the patient with a five-drug resistance pattern costs more than the county’s entire TB budget for the year, she adds. "The impact of a case like this is huge in a rural area like this."
That kind of scenario may be on the rise, too, she reasons. "The more we have an influx of foreign-born people, the more people will begin moving out from big urban areas."
Along with more drug resistance, Fields and Nolan found infectiousness more concentrated among foreign-born patients. In the 206 U.S.-born cases Nolan and Fields looked at from the past five years, 45% were smear-positive; among the 252 foreign-born cases from the same time period, 55% were smear-positive.
Foreign-born patients also are more likely to be female and are younger than U.S.-born cases, Fields says. "We’re seeing more females with TB among the foreign-born, not only because they tend to have poorer access to health care, but because women are more reluctant to identify themselves [to health care providers] due to the stigma associated with TB. They fear not being able to get married, or that they’ll be a burden to their families."
Finally, Fields and Nolan found more extrapulmonary TB among foreign-born cases, especially TB of the joint and spine. "The trend toward more extrapulmonary was slight and may not have been significant," she says. But when the two looked for a certain kind of extrapulmonary TB, they found that of 26 such cases, 63% had occurred among foreign-born patients. Bone and joint TB are notable for being hard to diagnose and harder to treat, typically requiring a long course of chemotherapy, long hospitalizations, and sometimes even surgery.
One recent case in King County, though extreme, illustrates the difficulties Fields says she’s up against more often these days. "This was a young Somali woman who didn’t speak English, who was pregnant, and who was mentally ill, with TB of the spine at the high cervical level," she says. "She didn’t believe in surgery, and, on top of that, clinicians had to work around the issue of her mental illness."
TB experts from other developed countries echo the same complaints as their TB caseloads shift toward more foreign-born, Field says. At a conference held by the International Union Against Tuberculosis and Lung Disease, Fields says she listened to a Danish TB expert talk about increased patient morbidity; at the same meeting, experts from developing countries also reported sicker patients.
Sadly, "what they were describing was the need for more outreach workers to simply go out and count patients who were dying," adds Fields. What’s needed now, she adds, are better ways to spot such trends as they occur, not after the fact.