He was a young man: 33 years old. When I entered the emergency room, I could see that he was gravely ill and struggling to breathe.
Although he was surrounded by family, he looked afraid. His family members confided in me that they could barely recognize him, as he had become so desperately thin in the past couple of weeks. He had contracted not only HIV but also tuberculosis (TB)—a dangerous combination that can hasten suffering and death.
The Caribbean region, after sub-Saharan Africa, has the highest HIV prevalence in the world, with the Dominican Republic (DR) and Haiti accounting for nearly three-quarters of the HIV cases in this area.
The DR is also believed to have one of the highest rates of TB in the Americas, according to the World Health Organization. It’s estimated by some researchers that between 6 and 11 percent of those with TB in the DR also are infected with HIV, presenting a dual challenge. La Romana, the third largest city in the DR, is located in one of the regions that are most seriously affected because of the high number of disenfranchised Haitian immigrants, poverty and the prolific tourism industry.
For the past year I have been working at Clínica de Familia La Romana, exploring the world of clinical research in the DR, with the support of a Doris Duke Clinical Research Fellowship. Clínica de Familia is a comprehensive community health services organization; it runs one of the largest HIV clinics in the country, in addition to primary-care services, an adolescent reproductive health clinic and a specialized clinic for sex workers, among other programs. I am currently conducting two studies here. One is focused on evaluating the role of vitamin D in the clinical course of co-infected patients, and the other explores the feasibility of using a blood test known as an immune-based whole blood IFN-γ release assay to detect TB among newly diagnosed HIV-positive individuals. Our goal is to improve the clinical algorithm currently used to diagnose HIV-associated TB at Clínica de Familia.
HIV-TB co-infection is particularly prevalent in populations with limited resources and limited access to care, which are closely linked to poverty and discrimination.
Diagnosis of TB in an HIV-infected individual is difficult due to the high rate of extrapulmonary disease; the need to distinguish TB from other infectious and neoplastic complications of HIV; and the high rate of atypical clinical presentation. Many co-infected individuals have few symptoms of TB, or the symptoms are less specific than usual. HIV-positive patients with TB frequently present with “subclinical” TB, which often is not recognized as TB, and consequently there are delays in both diagnosis and treatment for TB.
In low-resource settings, TB is typically diagnosed with a combination of an acid fast bacilli (AFB) smear, an AFB culture, and a chest X-ray. An AFB smear is used to determine if an infection may be due to one of the AFB, the most common of which is M. tuberculosis; however, HIV-associated TB is often AFB smear–negative, which increases the likelihood of a missed diagnosis.
Normally, getting the results of an AFB culture takes a minimum of six weeks, but here in La Romana it takes an average of three months, rendering the results clinically irrelevant. In addition, up to a fifth of people with both pulmonary TB and HIV have normal chest X-rays.
As a researcher I have seen firsthand the challenge of diagnosing TB in an HIV-positive patient in a low-resource setting. Because of the increased likelihood of atypical clinical presentation and the poor performance of standard diagnostic tools, HIV-positive patients with TB are being diagnosed largely by clinical presentation.
One of the most difficult realities of this urgently needed research is that at present, our efforts often come too late. The young patient co-infected with HIV and TB whom I encountered in the emergency room died that weekend in the hospital. His death reminds us of the steep road ahead in treating HIV-TB co-infection. But we remain steadfast in our commitment to diagnose both quickly and to initiate treatment sooner.
A previous version of this blog appeared on The EJBM blog.