Diagnosis and Management of Group a Streptococcal Pharyngitis in the United States, 2011–2015

Background Clinical guidelines for the diagnosis of group A streptococcal (GAS) pharyngitis recommend the use of a rapid antigen detection test (RADT) and/or bacterial culture. This study evaluated the overall diagnosis and treatment of acute pharyngitis in the United States, including predictors of test type and antibiotic prescription. Methods A retrospective analysis of pharyngitis events from 2011 through 2015 was conducted using the MarketScan commercial/Medicare databases. A pharyngitis event was defined as occurring within 2 weeks from the index visit. Patient and provider characteristics were examined across 5 testing categories: RADT, RADT plus culture, other tests, nucleic acid amplification testing (NAAT), and no test. Multivariate models were used to identify significant predictors of NAAT use and antibiotic prescription. Results A total of 18.8 million acute pharyngitis events were identified in 11.6 million patients. Roughly two-thirds of events (68.2%) occurred once, and roughly a third of patients (29.1%) required additional follow-up, but hospitalization was rare (0.3%). Across all events, 43% were diagnosed by RADT, while 20% were diagnosed by RADT plus culture. The proportion of events diagnosed by NAAT increased 3.5-fold from 2011 to 2015 (0.06% vs 0.27%). Antibiotic use was frequent (49.3%), less often in combination with RADT plus culture (31.2%) or NAAT alone (34.5%) but significantly more often with RADT alone (53.4%) or no test (57.1%). Pediatricians were significantly less likely than other providers to prescribe antibiotics in their patients, regardless of patient age (p