Mayo Clin Proc. • September 2006;81(9):1172-1176 • www.mayoclinicproceedings.com 1172 REPEATED GROUP A β-HEMOLYTIC STREPTOCOCCAL PHARYNGITIS EPISODES Population-Based Prevalence of Repeated Group A β-Hemolytic Streptococcal Pharyngitis Episodes ORIGINAL ARTICLE From the Division of Epidemiology (J.L.S., S.J.J.), Division of Biostatistics (A.L.W.), Department of Otorhinolaryngology (L.J.O.), and Department of Pedi- atric and Adolescent Medicine (R.M.J.), Mayo Clinic College of Medicine, Rochester, Minn. Dr Jacobsen is now with Southern California Permanente Medical Group, Pasadena, Calif. Individual reprints of this article are not available. Address correspondence to Jennifer L. St. Sauver, PhD, Division of Epidemiology, Mayo Clinic College of Medicine, 200 First St SW, Rochester, MN 55905 (e-mail: stsauver.jennifer @mayo.edu). © 2006 Mayo Foundation for Medical Education and Research JENNIFER L. ST. SAUVER, PHD; AMY L. WEAVER, MS; LAURA J. ORVIDAS, MD; ROBERT M. JACOBSON, MD; AND STEVEN J. JACOBSEN, MD, PHD OBJECTIVE: To define the population-based 3-year period preva- lence of repeated group A β-hemolytic streptococcal (GABHS) pharyngitis episodes in children between 4 and 15 years of age. PATIENTS AND METHODS: Residents of Rochester, Minn (age, 4- 15 years), who had 3 or more GABHS pharyngitis episodes in 1 year, at least 1 month apart, between January 1, 1996, and December 31, 1998, were identified using the resources of the Rochester Epidemiology Project (N=536). Pharyngitis episodes (evidence of a sore throat with or without presence of fever) followed by either a positive rapid streptococcus test result or a positive plate culture test result were considered positive GABHS episodes. Age- and sex-specific prevalence rates were calculated, assuming that all residents 4 to 15 years of age in Rochester during 1996 to 1998 were at risk. RESULTS: A total of 208 children met our definition for repeated GABHS episodes between 1996 and 1998 and were included in this study. Approximately 1% of children between the ages of 4 and 15 years experienced repeated GABHS pharyngitis episodes between 1996 and 1998. This estimate increased to approxi- mately 2% among children 4 to 6 years of age and decreased to 0.1% among children 13 to 15 years old. CONCLUSION: A relatively small proportion (1%) of children be- tween 4 and 15 years of age experienced repeated GABHS epi- sodes in a 3-year period; however, this proportion represents a substantial number of children who are affected at the population level. Given the increased costs associated with treating repeated GABHS episodes, further studies are necessary to determine how best to reduce episodes and treatment costs in this age group. Mayo Clin Proc. 2006;81(9):1172-1176 CI = confidence interval; GABHS = group A β-hemolytic streptococcal; REP = Rochester Epidemiology Project G roup A β-hemolytic streptococcal (GABHS) infec- tions are a common cause of childhood pharyngitis episodes, accounting for approximately 15% to 30% of all pharyngitis cases. 1 Typically, GABHS pharyngitis is a mild illness that resolves without complications after appropri- ate antibiotic treatment. However, some children experi- ence repeated episodes of GABHS-associated pharyngitis, despite appropriate antibiotic therapy, which may place them at increased risk of complications, such as peritonsillar abscess and acute rheumatic fever. In addition, Roos et al 2 have estimated that a single tonsillitis episode may cost $385 (in US dollars) in treatment costs, travel time, and loss of guardian’s work productivity. Children who have 3 to 4 or more tonsillar infections per year, despite adequate medical therapy, may also become candidates for tonsillectomy. 3,4 Therefore, families with children who have repeated GABHS pharyngitis may experience especially high health care–associated costs because of the need for frequent treatment, lost parental work time, and tonsillectomy. A study by Pichichero et al 5 suggests that single recur- rences of GABHS pharyngitis episodes have almost tripled since 1975. However, it is unclear how many children continue to experience repeated GABHS episodes, beyond a single re- currence, despite appropriate antibi- otic treatment. The precise scope of this problem is poorly understood be- cause population-based estimates of the prevalence of re- peated GABHS pharyngitis are difficult to obtain. Children tend to obtain care for GABHS pharyngitis from a variety of different clinics, acute care facilities, and emergency departments, making it difficult to track and document true GABHS episodes. Thus, we took advantage of the com- plete and detailed medical record information available through the Rochester Epidemiology Project (REP) to ob- tain population-based prevalence data of repeated GABHS pharyngitis episodes in children 4 to 15 years of age. PATIENTS AND METHODS DESCRIPTION OF STUDY RESOURCES Olmsted County, Minnesota, is served by a largely unified medical care system that has accumulated comprehensive clinical records since the early 1900s. The REP is a unique resource that links and indexes the records of virtually all providers of medical care to Olmsted County residents. 6 The result is the linkage and availability of medical records (including details of every outpatient visit to of- fices, clinics, and emergency departments, as well as ev- ery laboratory result and all correspondence concerning each patient) from essentially all sources of medical care For editorial comment, see page 1153 For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings. For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.