Home Test for Pharyngitis May Reduce Unneeded Strep Cultures.


A patient-driven approach to streptococcal pharyngitis diagnosis using a new home test score might save on unnecessary physician visits, cultures, and treatment, according to a retrospective cohort study published online November 4 in the Annals of Internal Medicine. However, some experts are skeptical of the home score algorithm and of its potential cost-savings.

“Globally, group A streptococcal (GAS) pharyngitis affects hundreds of millions of persons each year,” write Andrew M. Fine, MD, MPH, from the Division of Emergency Medicine-Main 1, Boston Children’s Hospital in Massachusetts, and colleagues. “In the United States, more than 12 million persons make outpatient visits for pharyngitis; however, clinicians cannot differentiate GAS pharyngitis from other causes of acute pharyngitis (for example, viral) on the basis of a physical examination of the oropharynx.”

Most cases of sore throat are viral, rather than bacterial, and therefore are self-limiting and transient even without antibiotic treatment. To classify risk for GAS pharyngitis and guide management of adults with acute pharyngitis, the American College of Physicians and Centers for Disease Control and Prevention recommend use of clinical scores to identify low-risk patients. According to consensus guidelines, such patients should not be tested or treated for GAS pharyngitis.

The goal of this study was to help patients decide when to visit a clinician for evaluation of sore throat. The study sample consisted of 71,776 patients at least 15 years of age who were evaluated for pharyngitis from September 2006 to December 2008 at one of a national chain of retail health clinics.

Using information from patient-reported clinical variables, as well as local incidence of GAS pharyngitis, the investigators created a score and compared it with the Centor score and other traditional scores, using information from clinicians’ assessments. Clinical variables in the new score were fever, absence of cough, and age.

The investigators estimated outcomes if patients who were at least 15 years of age with sore throat did not visit a clinician when the new score indicated less than 10% likelihood of GAS pharyngitis, compared with being managed by clinicians following guidelines using the Centor score. The researchers suggest that following this strategy would avoid 230,000 clinician visits in the United States each year, and that 8500 patients with GAS pharyngitis who would have received antibiotics under clinician management would not receive antibiotics.

A limitation of this approach is current lack of availability of real-time information about the local incidence of GAS pharyngitis, which is needed to calculate the new score. Study limitations include retrospective design and reliance on self-report of symptoms.

“A patient-driven approach to pharyngitis diagnosis that uses this new score could save hundreds of thousands of visits annually by identifying patients at home who are unlikely to require testing or treatment,” the authors write.

Experts Question Limitations and Cost-Savings of the New Score

In an accompanying editorial, Edward L. Kaplan, MD, MMC, from the Department of Pediatrics, University of Minnesota Medical School in Minneapolis, warns of limitations of the new home score. These include overly broad age range, as GAS pharyngitis is rare in persons older than 50 years, and the assumption that GAS pharyngitis has even prevalence across communities.

Dr. Kaplan recommends stratification by age categories and notes that uncomplicated GAS pharyngitis has not been reportable to health departments for several decades in most states, making incidence difficult to determine. Other limitations include failure to account for potential effects of the decisions made by the multiple clinicians from more than 70 clinics attended by patients in this sample, and lack of differentiation of true GAS infection from upper respiratory tract “carriers” among adults.

“Until we have a proven cost-effective vaccine to protect against Streptococcus pyogenes, we cannot expect the magnitude of this medical and public health issue to decrease,” Dr. Kaplan writes. “Even if a cost-effective vaccine is developed, how it may affect true infections and the carrier state in children may be entirely different in adults. Fine and colleagues have proposed an interim approach, but there are surely others.”

In a second editorial, Robert M. Centor, MD, from the University of Alabama at Birmingham in Huntsville, questions the potential cost-savings if the new score were widely used. Alternative strategies to improve treatment and reduce costs include clinical assessment that eliminates testing for patients at low risk, as well as the use of generic antibiotics for those with GAS pharyngitis. He also warns that all guidelines and recommendations for GAS pharyngitis apply only to patients who have had symptoms for fewer than 3 days.

“If symptoms persist or worsen, then the patient no longer has acute pharyngitis; therefore, we should use a different diagnostic and therapeutic approach,” he writes.

Other questions posed by Dr. Centor include whether patients would actually download and use such a test before deciding whether to seek medical care for sore throat and why many physicians, clinics, and emergency departments do not follow published guidelines recommending against antibiotic use for patients with low probability of GAS pharyngitis.

“Although the goals [of this study] are admirable, the approach does not seem practical or cost-saving,” Dr. Centor concludes. “We have more practical strategies for decreasing costs for patients with sore throat.

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