A new study shows that while the risk of dying of rheumatic heart disease has fallen over the past 25 years, the disease stubbornly persists in the world’s poor regions, where penicillin is either unavailable or too costly.
The study appeared in The New England Journal of Medicine and was co-authored by Professor Bongani Mayosi, dean of the Faculty of Health Sciences. Titled “Global, Regional and National Burden of Rheumatic Heart Disease, 1990–2015”, it is the first global study of its kind to track the disease over a 25-year period.
Rheumatic heart disease is a condition of damaged heart valves caused by bacterial infection, often untreated strep throat, which leads to rheumatic fever.
While gains have been made in curbing the disease, progress remains uneven. In several regions that include some of the world’s poorest countries, mortality from rheumatic heart disease has not appreciably declined since 1990. Neither has the number of people living with rheumatic heart disease.
The study shows that there were an estimated 347 500 deaths from the disease in 1990 and 319 400 in 2015 – an 8% decrease. The global age-standardised death rate decreased from 9.2 per 100 000 in 1990 to 4.8 per 100 000 in 2015, a reduction of 48%. The countries with the highest estimated numbers of rheumatic heart disease deaths were India, China, Pakistan, Indonesia and the Democratic Republic of the Congo. These five nations account for 73% of global deaths from the disease.
The disease is often a long-term consequence of untreated strep throat, which can be highly contagious, especially for children living in overcrowded and unsanitary settings. In susceptible individuals, untreated strep throat can lead to rheumatic heart disease and heart valve damage over time. Symptoms can appear 10 to 20 years after the original infection and can disable or kill individuals during their prime working years. Pregnant women are also at very high risk.
Social factors such as education, income and lack of access to healthcare have tracked closely with the disease.
“Children living in informal settlements and impoverished communities with poor access to health care are therefore most at risk,” says Mayosi. “Yet it can be treated with penicillin.”
Better care and data
Lead author Dr David Watkins, of the University of Washington School of Medicine and an honorary professor at UCT, says that while cost-effective interventions are available for strep throat, many children don’t have access to adequate care.
About 1% of school children in endemic countries show evidence of rheumatic heart disease. As a result, their heart conditions usually worsen with age and lead to premature death.
“Most of these individuals could be saved by open-heart surgery to repair or replace the damaged valves, but unfortunately in these countries access to advanced cardiology and cardiac care is very low,” says Watkins.
The study has also highlighted the need for better data on the disease prevalence and mortality. Countries where rheumatic heart disease is endemic need stronger national surveillance systems and more studies on the prevalence of the disease, especially among adults, says senior author of the study, Gregory Roth, assistant professor at the University of Washington.
The paper is based on the annual Global Burden of Disease Study (GBD), the world’s largest health science enterprise, examining 400 diseases, injuries and risk factors among all age groups in 195 countries.