RF Primary Prevention

Treat kids with sore throats to curb RF in South Africa

NOVEMBER 4, 2012 Lisa Nainggolan
Los Angeles, CA - A strategy of treating all children in developing countries who present with a sore throat with a one-off injection of penicillin to prevent development of acute rheumatic fever and rheumatic heart disease in a minority would be cost-effective and save lives, a new statistical analysis shows.

Dr Thomas Gaziano

And factoring in the existence of one or more symptoms suggestive of "strep throat"—such as enlarged lymph nodes, absence of rhinitis, and absence of fever—further increases the likelihood that a child actually has a streptococcal infection and would therefore benefit from a penicillin injection, says Dr Thomas Gaziano (Brigham and Women's Hospital, Boston, MA), who presented his findings during a poster session here today at the American Heart Association 2012 Scientific Sessions.

But what is not cost-effective is performing throat swabs on these children, says Gaziano, who modeled the findings based on previously published research. "Cultures cost more than treating everyone and save fewer lives," he told heartwire.

Which strategy should be used to screen children with sore throats?

Rheumatic heart disease is the most important sequela of acute rheumatic fever, which is caused by group A streptococci (GAS) and usually begins as pharyngitis, or "strep throat." Rheumatic fever is extremely rare in industrialized countries, but the condition is still a major problem in developing nations. It primarily affects five- to 15-year-olds, causing up to 500 000 deaths annually and disabling hundreds of thousands of people due to subsequent development of rheumatic heart disease. There has been much debate about the best way to prevent initial attacks (so-called primary prevention).

This can be achieved with a one-off injection of penicillin, costing between $1 and $10, in those with a sore throat to prevent the development of rheumatic fever. However, only 15% to 25% of those who present with a sore throat will have GAS, and therefore there have been concerns about the cost-effectiveness of this approach and anaphylactic reactions to penicillin.

But others contend that not instituting primary-prevention programs is a wasted opportunity to nip the disease in the bud. A group in South Africa, led by Dr Bongani M Mayosi (Groote Schuur Hospital and University of Cape Town, South Africa), has previously estimated that only 60 children per year would need to be treated to prevent one episode of rheumatic fever, at a cost of $46 per episode prevented. And this approach has been successful in countries such as Cuba and Costa Rica. Despite evidence such as this, none of the guidelines currently support primary prevention, Gaziano explained.

"This is really about which test we should use to screen children who present with sore throat before we make a decision about whether to treat them with intramuscular injections of penicillin," Gaziano explained. "One strategy is to not do any screening and not to treat, another is to do no screening but treat everybody. In between that is a strategy of performing a throat culture and, if it's positive, we initiate treatment."

"We evaluated what would happen in each of those strategies using previously published data on the prevalence of group A strep, treatment rates, and costs, from South Africa, as well as using data on treatment effects, benefits, and side effects from a number of international studies."

Treating everybody is cheap and saves lives

"The data suggest that if you want to save the most lives it's not a bad strategy to treat everybody," Gaziano toldheartwire. "We broke it up in terms of number of deaths related to the side effects vs [deaths from] rheumatic heart fever, and clearly if you don't treat any kids, you have 168 deaths per million cases of pharyngitis—and none from anaphylaxis—whereas if you treat everybody, you have more anaphylaxis [10 deaths per million cases of pharyngitis], but you have far fewer deaths related to rheumatic heart disease."

If you treat everybody you have more anaphylaxis, but you have far fewer deaths related to rheumatic heart disease.

While some previous trials that have looked at treating all children with symptoms of strep throat have not found this to be feasible or cost-effective, these studies have traditionally recruited children at schools, he says. "But we're talking about a different scenario: assessing children with sore throats who present at medical centers."

And if people feel uncomfortable about treating everybody, they can instead use the "clinical decision rules" advocated by agencies such as the World Health Organization, he notes, which involves examining kids for the symptoms that increase the likelihood that their sore throat is caused by group A strep, such as enlarged lymph nodes.

But the new research indicates that performing throat swabs is a waste of time, he stresses, because it increases costs and saves fewer lives. "In some of these places, people don't come back for the culture results, so you can lose the opportunity to treat somebody," he observes.

Gaziano calculated the cost per person of a "treat-everyone" strategy would be $14.70, while that of basing treatment on the existence of two clinical symptoms of "strep throat" would be $16.15. This compares with a cost of $31.01 for performing cultures on everyone. He has now submitted his research for publication.