March 21, 2016
On the frontlines
Strengthening tuberculosis treatment in Massachusetts
By Laurie Covens
Amid rising concern about tuberculosis (TB) as a lethal global threat and the emergence of virulent drug resistant forms of the disease, Heller School senior research associate Cynthia Tschampl, PhD’15, has become a leading voice in the push for crucial TB control strategies.
While also working closely with the Massachusetts Department of Public Health and advocates across the nation, Tschampl conducts research aimed at strengthening the health care infrastructure needed to tackle TB. Her study, recently published in the CDC’s Emerging Infectious Disease Journal, proposed a methodology to assess and better manage TB rates and treatment interruption in highly mobile populations.
Failure to complete TB treatment contributes to the rise of multi-drug resistant TB (MDR-TB), which is far more deadly and expensive to treat. While active TB can require yearlong treatment and cost up to $50,000 per case, treating MDR-TB requires two years of treatment and costs approximately $250,000, including a daunting drug regime with often very toxic side effects.
The World Health Organization (WHO) reports an estimated half a million new MDR-TB cases worldwide each year. The U.S. accounts for roughly 100 of those new MDR-TB cases, or one percent of new TB cases in the U.S. Massachusetts had seven new cases in 2015—close to four percent. That is slightly larger than even the global rate, and ties for the highest number ever recorded in Massachusetts.
Why is Massachusetts’ MDR-TB incidence rate so high? Tschampl thinks it’s because Massachusetts is a major port of entry, with a more globalized economy and community and a population that is more likely to travel abroad for education, business, and volunteer efforts. Global travel and migration often cause people to discontinue medical treatment. Since more than half of patients with active TB in the U.S. are foreign-born, Tschampl and her colleagues decided to investigate how many foreign-born visitors and temporary residents leave the U.S. before completing TB treatment. Based on data for 2008-2012, their study reported that slightly more than 2,800 such patients a year left the U.S. and were at risk for TB treatment interruption.
While global health systems currently lack the ability to track these cases and ensure treatment continuity, Tschampl says her team’s study is a key step forward.
“Clearly identifying a population at high risk for treatment interruptions means now there’s an opportunity to respond,” she explains. “And we found a proven strategy to ensure treatment completion. Two groups - Cure TB and the Migrant Clinicians Network - provide cost-effective transnational case management for about eight percent of the mobile population we studied and their treatment completion rates approach WHO’s goal of 85 percent.”
In the 1970’s, American doctors thought they had eradicated TB. Today this airborne disease is the top infectious disease killer worldwide, causing nearly two million deaths a year. But those numbers only reflect the impact of active TB. More than two billion people worldwide have “latent TB infection (LTBI),” a mostly non-contagious form of the disease that can convert to active TB if left untreated. The U.S. has an estimated 13 million people with LTBI, and 300,000 of those are in Massachusetts. Given the magnitude of these numbers, Tschampl rejects the prevailing terminology.
“Words like ‘inactive’ and ‘latent,’ are misleading,” she says, “because this precursor form of the disease is really the reservoir of future cases. Just look at Massachusetts. Most active TB cases in Massachusetts are the result of inactive cases becoming active. We have about 9,000 newly diagnosed TB infections a year. Meanwhile, we haven’t seen a real decline in active case rates for a decade.”
Most active TB cases in Massachusetts are the result of inactive cases becoming active...we haven't seen a real decline in active case rates for a decade.
Why the stalemate in Massachusetts? Just decades ago, the state had 24 tuberculosis clinics providing immediate TB infection treatment and aggressive contact-tracing to limit contagion. But Tschampl says flagging state support has weakened the system, which now has only about 17 clinics.
Yet treating TB infection is crucial to TB control. “You can treat tuberculosis before it goes active, when it’s in the infection stage,” Tschampl explains. “Since we don’t have an effective vaccine, that’s the only way to prevent someone from developing active TB and infecting others.”
That is why Tschampl advocates making TB infection screening a routine part of primary care for higher risk populations. In a 2011 paper published in the Joint Commission Journal on Quality and Patient Safety, she and her colleagues created performance measures to help ease the integration of TB preventive services into the primary care sector. Effective LTBI screening and treatment could reduce conversion to active TB by 90 percent, they said.
Persuading primary care clinicians to move in this direction is no easy feat. A recent Health Affairs article noted that many primary care physicians today have little experience treating or diagnosing TB. But Tschampl thinks the Affordable Care Act’s focus on preventive health care, Massachusetts’ healthcare cost reform law, and the brand-new “B” grade released by the U.S. Preventive Services Task Force (USPSTF) may be just the leverage needed for primary care clinicians serving populations at high risk to embrace TB screening and prevention services.
Tschampl’s instinct for using health care policy to improve TB control explains why she was initially drawn to Heller’s PhD program—and why she stayed on as a researcher. “I was an anti-poverty and immigrant rights advocate long before starting my academic career,” she explains. “That’s how I learned that TB is both a cause – and a result of – poverty. So beating it means grappling with social and economic justice issues. Heller gave me the tools to do just that – which is why it’s been a perfect fit for me.”
Tschampl's work has also been reviewed by the Migrant Clinician's Network, who recently published a Q&A with her about this study and about her thoughts on the future of tuberculosis research.