In this issue of Infectious Diseases in Clinical Practice, Fakih et al1 have evaluated the diagnosis and treatment of acute pharyngitis patients by emergency department physicians in a 609-bed tertiary care hospital during the year 2000. They found the standard of practice to vary markedly from the national practice guideline published by the Infectious Diseases Society of America (IDSA)2 in the following specifics: a throat culture and/or rapid antigen detection test (RADT) was obtained in only 36% of encounters, and antibiotics were prescribed for 89% of those not tested and for one quarter of those whose diagnostic tests were negative. Generally similar findings were reported in a 1993 to 1994 survey of a sample of Kentucky Medicaid claims for tonsillopharyngitis in children seen in either outpatient clinics or emergency rooms.3
These findings raise questions both as to the reasons for and implications of such noncompliance. Cabana et al4 in an article entitled "Why Don't Physicians Follow Clinical Guidelines?" ascertained that the barriers to compliance fell into 1 of 3 general categories. One of these, lack of knowledge, seems unlikely in this case. The IDSA guidelines were first published in 19972 (and were subsequently updated in 20025), but they are quite similar to long-established recommendations of the American Heart Association (AHA)6 and the American Academy of Pediatrics (AAP).7 Although the most recent iterations of these statements differ in some details, all strongly counsel performance of a diagnostic test (throat culture and/or RADT) in patients whose signs and symptoms are compatible with the diagnosis of "strep throat." They furthermore caution against administration of antibiotic therapy to patients whose tests are negative for the presence of group A streptococci (GAS) in the pharynx. A second potential barrier to compliance is attitudinal, that is, lack of agreement with the practice guideline (eg, impractical and not cost-beneficial) or lack of expectancy of a favorable outcome. Some physicians may question the cost-benefit of performing a laboratory diagnostic test for this common illness or may be overconfident in their ability to diagnose strep throat on physical examination8 (more about this below). Finally, behavioral factors such as patient preference, fear of adverse outcome, or even fear of malpractice actions by withholding antibiotics may come into play. A special concern among emergency room physicians may be the inability in many instances to achieve continuous follow-up of problematic cases.
Unanimity by such prestigious groups as AHA, AAP, and IDSA should hopefully combat the attitudinal and behavioral barriers or at least provide ample authoritative support for primary care providers who adhere to the established guidelines. At any rate, if the Fakih et al data are representative, there is a major educational job to do among emergency room physicians.
It is perhaps appropriate at this point to review briefly the rationale for the IDSA, AHA, and AAP guidelines for diagnosis and management of strep throat. Acute pharyngitis is an extremely common complaint in primary care, responsible for some seven million visits of children to primary care providers annually in the United States.9 Most cases are viral in etiology. Group A streptococcus is responsible for approximately 20% to 30% of cases in children and 10% in adults. It is the only commonly occurring agent of pharyngitis for which antibiotics are required.10 Antibiotics are given to prevent acute rheumatic fever and suppurative complications, improve signs and symptoms, decrease infectivity, and reduce transmission to close contacts. However, currently in the United States, acute rheumatic fever is extremely uncommon as are serious suppurative complications of strep throat such as peritonsillar abscess. Group A streptococcus pharyngitis is usually self-limited even without antimicrobial therapy, and such therapy reduces the febrile period by only approximately 16 hours overall.11 Given the modest benefits of antimicrobial therapy, treatment should be limited to patients with documented strep throat and withheld from the great majority of patients with viral pharyngitis, for whom these agents offer no benefit but confer risk of adverse reactions. Moreover, to the extent that broad-spectrum agents (rather than penicillin) are utilized profligately in treatment of acute pharyngitis, adverse effects on health care costs and antimicrobial resistance are to be anticipated.
Since the year 2000, when the studies of Fakih et al were performed, an additional clinical practice guideline regarding management of acute pharyngitis in adults has been published.12,13 This guideline is endorsed by the Centers for Disease Control and Prevention (CDC), the American College of Physicians-American Society of Internal Medicine (ACP), and the American Academy of Family Physicians. The CDC-ACP guideline uses a clinical algorithm developed by Centor et al,14 which relates the probability of GAS pharyngitis to 4 clinical findings: tonsillar exudates, tender anterior cervical adenopathy, absence of cough, and history of fever. The ACP practice guideline is published in 2 articles12,13 whose recommendations actually differ slightly. Although this guideline allows for the use of RADT, the first recommended strategy in the article of Snow et al13 is for empirical antibiotic treatment of adults with at least 3 of 4 Centor clinical criteria and no treatment of all others. In previous commentary, I have pointed out that, in the Centor et al study,14 only approximately 40% of adult pharyngitis patients presenting to an emergency department with 3 or more criteria had positive throat cultures for GAS.15,16 Thus, 60% of the patients so empirically treated would have had negative throat cultures. Other similar studies have yielded comparable results in adults.17 This is particularly disturbing because the stated goal of the guideline is "dramatically decreasing antibiotic use."13 In reply, the CDC-ACP authors rightly pointed out that an empiric strategy is to be preferred over the current situation in which physicians continue to prescribe antibiotics to 75% of adult sore throat patients.18 In an attempt to reach a middle ground, the 2002 IDSA guidelines no longer require a culture backup of a negative RADT in adult patients. As further data emerge and technology advances, it may become possible to adopt this approach for children as well.
The authors of the CDC statement indicated that studies should be conducted to compare the various strategies in terms of relevant patient outcomes and cost. Such studies have now appeared. Neuner et al19 conducted a cost-effectiveness analysis of several strategies for management of acute pharyngitis in adults, including observation without testing or treatment, empirical treatment with penicillin, throat culture, RADT using the optical immunoassay with negatives confirmed by culture, and RADT alone. They concluded that "empirical treatment was not the most effective or least expensive strategy at any prevalence of GAS pharyngitis in adults." McIsaac et al20 compared the IDSA and CDC-ACP strategies in 787 children and adults with acute pharyngitis attending a family medicine clinic in Calgary, Alberta, Canada. They found that, in everyday practice, "empirical treatment of adults having a Centor score of 3 or 4 is associated with a high rate of unnecessary antibiotic use."
In summary, evidence-based guidelines that use microbiologic testing are the preferred strategy for both identifying and treating patients with GAS pharyngeal infection and, equally important, minimizing unnecessary and potentially deleterious antimicrobial usage. Clinical algorithms are helpful in identifying patients whose risk of GAS infection is so low that neither a diagnostic test nor antimicrobial treatment is advisable. It is discouraging that so many primary care providers continue to overprescribe antimicrobials for acute pharyngitis. Empiric algorithm-based treatment, however, is not, in my opinion, to be preferred in developed countries such as the United States with ready availability of office-based or laboratory testing facilities and a very low incidence of rheumatic fever. The IDSA guidelines provide specific indicators of quality of care. Monitoring of these indicators may be used to determine readily whether the standard of care is being met in any particular patient-care setting. Further studies of the efficacy of specific interventions, either educational or technologic, in facilitating utilization of evidence-based practice guidelines are clearly required.
1. Fakih MG, Berschback J, Juzych NS, et al. Compliance of resident and staff physicians with IDSA guidelines for the diagnosis and treatment of streptococcal pharyngitis. Infect Dis Clin Pract
2. Bisno AL, Gerber MA, Gwaltney JM Jr, et al. Diagnosis and management of group A streptococcal pharyngitis: a practice guideline. Clin Infect Dis.
3. Mainous AG III, Zoorob RJ, Kohrs FP, et al. Streptococcal diagnostic testing and antibiotics prescribed for pediatric tonsillopharyngitis. Pediatr Infect Dis J.
4. Cabana MD, Rand CS, Powe NR, et al. Why don't physicians follow clinical practice guidelines? A framework for improvement. JAMA
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19. Neuner JM, Hamel MB, Phillips RS, et al. A cost-effectiveness analysis of diagnosis and management of adults with pharyngitis. Ann Intern Med.
20. McIsaac WJ, Kellner JD, Aufricht P, et al. Empirical validation of guidelines for the management of pharyngitis in children and adults. JAMA.