A postmortem study by Ted Cohen and colleagues reveals a huge toll of tuberculosis among patients dying in hospitals in KwaZulu-Natal, South Africa.
Tuberculosis is the leading cause of death in South Africa by death notification, but accurate diagnosis of tuberculosis is challenging in this setting of high HIV prevalence. We conducted limited autopsies on young adults dying in a single public hospital in the province of KwaZulu-Natal between October 2008 and August 2009 in order to estimate the magnitude of deaths attributable to tuberculosis.
Methods and Findings
We studied a representative sample of 240 adult inpatients (aged 20–45 years) dying after admission to Edendale Hospital. Limited autopsies included collection of respiratory tract secretions and tissue by needle core biopsies of lung, liver, and spleen. Specimens were examined by fluorescent microscopy for acid-fast bacilli and cultured in liquid media; cultures positive for M. tuberculosis were tested for drug susceptibility to first- and second-line antibiotics. Ninety-four percent of our study cohort was HIV seropositive and 50% of decedents had culture-positive tuberculosis at the time of death. Fifty percent of the participants were on treatment for tuberculosis at the time of death and 58% of these treated individuals remained culture positive at the time of death. Of the 50% not receiving tuberculosis treatment, 42% were culture positive. Seventeen percent of all positive cultures were resistant to both isoniazid and rifampin (i.e., multidrug resistant); 16% of patients dying during the initiation phase of their first ever course of tuberculosis treatment were infected with multidrug-resistant bacilli.
Our findings reveal the immense toll of tuberculosis among HIV-positive individuals in KwaZulu-Natal. The majority of decedents who remained culture positive despite receiving tuberculosis treatment were infected with pan-susceptible M. tuberculosis, suggesting that the diagnosis of tuberculosis was made too late to alter the fatal course of the infection. There is also a significant burden of undetected multidrug-resistant tuberculosis among HIV-coinfected individuals dying in this setting. New public health approaches that improve early diagnosis of tuberculosis and accelerate the initiation of treatment are urgently needed in this setting.
Please see later in the article for the Editors' Summary
Every year, nearly 10 million people develop tuberculosis—a contagious bacterial infection that affects the lungs and other parts of the body—and nearly two million people die from the disease. Tuberculosis is caused by Mycobacterium tuberculosis, which spreads in airborne droplets when people with the disease cough or sneeze. Its characteristic symptoms are a persistent cough, weight loss, and night sweats. Diagnostic tests for tuberculosis include the microscopic examination of sputum samples (mucus brought up from the lungs by coughing) for M. tuberculosis bacilli, and mycobacterial culture (in which bacteriologists try to grow M. tuberculosis from sputum or tissue samples). Although tuberculosis can be cured by taking several powerful antibiotics regularly for at least 6 months, global efforts to control tuberculosis are being thwarted by the emergence of strains of M. tuberculosis that are resistant to several antibiotics (multidrug and extensively drug-resistant tuberculosis) and by the HIV epidemic; people who are infected with HIV, the virus that causes AIDS, are particularly susceptible to tuberculosis because of their weakened immune system.
Why Was This Study Done?
In the past few years, tuberculosis has become the leading recorded cause of death in South Africa, a country where nearly a fifth of adults are infected with HIV. There are 122,000 recorded deaths from tuberculosis (including 94,000 deaths in HIV-positive people) in South Africa every year. However, because the accurate diagnosis of tuberculosis in HIV-positive people can be difficult—they are more likely to have sputum-negative tuberculosis than HIV-negative individuals—the true number of people dying because of tuberculosis is likely to be higher than the recorded number. Public-health experts in South Africa need an accurate picture of the tuberculosis deaths to help them improve tuberculosis control. In this postmortem study, the researchers determine the prevalence (the proportion of a population that has a disease) and drug sensitivity of tuberculosis among patients dying in a public hospital in KwaZulu-Natal, South Africa, to get a better estimate of how many people die because of tuberculosis in this setting.
What Did the Researchers Do and Find?
The researchers collected respiratory tract secretions and lung, liver, and spleen samples from 240 adults who died in the Edendale public hospital in KwaZulu-Natal over a 10-month period in 2008/9. They looked for M. tuberculosis bacilli in the samples, tried to culture M. tuberculosis from them, and tested any bacteria that grew for antibiotic sensitivity. They also collected information on current tuberculosis treatment status, previous tuberculosis treatment, and HIV status for each deceased patient (decedent) from medical records and from relatives. Ninety-four percent of the decedents were HIV positive and 50% had culture-positive tuberculosis at the time of death. Of the 50% of the decedents who were being treated for tuberculosis, 58% were culture positive at the time of death. A similar percentage (42%) of the decedents who were not being treated for tuberculosis were culture positive at the time of death. Seventeen percent of all the positive cultures were multidrug resistant and 16% of patients dying during their first course of tuberculosis treatment were infected with multidrug-resistant bacteria. Seventy percent of decedents who remained culture positive despite receiving tuberculosis treatment were infected with M. tuberculosis strains that were susceptible to all antibiotics.
What Do These Findings Mean?
These findings reveal the immense toll of tuberculosis among HIV-infected individuals in this hospital in KwaZulu-Natal. They show that many patients being treated for tuberculosis were culture positive at death despite being infected with antibiotic-sensitive M. tuberculosis, which suggests that diagnoses of tuberculosis are often made too late to alter the fatal course of infection. These findings also suggest that multidrug-resistant tuberculosis often goes undetected among HIV-infected individuals. Further studies are needed to confirm these findings elsewhere in South Africa and in other countries with a high HIV prevalence. Nevertheless, they suggest that public-health initiatives that improve the early diagnosis of tuberculosis, that introduce routine screening for tuberculosis among HIV-positive patients, and that accelerate the initiation of treatment for both tuberculosis and HIV might reduce the global death toll from tuberculosis.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000296.
The World Health Organization provides information on all aspects of tuberculosis, including information on tuberculosis and HIV, on tuberculosis in South Africa, and on the Stop TB Partnership (some information is in several languages)
The US Centers for Disease Control and Prevention has information about tuberculosis and on tuberculosis and HIV coinfection
The US National Institute of Allergy and Infectious Diseases also has detailed information on all aspects of tuberculosis
Information is available from Avert, an international AIDS charity, on tuberculosis and HIV