Methods: We conducted a cross-sectional analysis of the nationally-representative National Ambulatory Medical Survey and National Hospital Ambulatory Medical Survey by adults with sore throat to primary care physicians and emergency departments (EDs) between 1997 and 2010 in 2-year periods (n = 8,191 sampled visits). We calculated the overall antibiotic prescribing rate and the prescribing rate for penicillin, erythromycin, azithromycin, amoxicillin, other 2nd-line antibiotics (1st-generation cephalosporins, clindamycin, or clarithromycin), and non-recommended antibiotics.
Results: Between 1997 and 2010, there were 94 million (95% confidence interval [CI], 86 to 102 million) visits by adults to primary care practices and EDs in the United States. Physicians prescribed antibiotics at 60% (95% CI, 57 to 63) of visits. From 1997-1998 to 2009-2010, the overall national antibiotic prescribing rate did not change (p = 0.31). In the same time period, there was no change in the rate of antibiotic prescribing by office-based physicians (61%; 95% CI, 58 to 64) or EDs (55%; 95% CI, 53 to 57; both p for trend > 0.33). Penicillin prescribing remained stable at 9% of visits (13% in 1997-1998 and 7% in 2009-2010; p = 0.27). Erythromycin prescribing rates were consistently below the threshold of reliable measurement. Azithromycin prescribing increased from below the threshold of reliable measurement in 1993-1994 to 15% of visits in 2009-2010 (p < 0.001). Other 2nd-line antibiotic prescribing decreased from 8% in 1997-1998 to below the threshold of reliable measurement in 2009-2012 (p = 0.01). There was no change in the prescribing rate for amoxicillin (17%; p = 0.33) or non-recommended antibiotics (15%; p = 0.07).
Conclusion: Physicians prescribed antibiotics to 60% of adults with sore throat between 1997 and 2010. Physicians prescribed broad-spectrum, expensive, or non-recommended antibiotics while prescriptions for penicillin remained stable and infrequent at 9% of visits.