Antibiotic prescribing for patients with colds, upper respiratory tract infections, and bronchitis: A national study of hospital-based emergency departments

Abstract

Study Objective: Antibiotics are often used to treat viral upper respiratory tract infections, even though they are usually ineffective. However, frequent inappropriate antibiotic use contributes to the emergence of drug-resistant bacterial pathogens. This study used a national database to evaluate antibiotic use in treating upper respiratory tract infections in emergency departments. Methods: Data were obtained from the 1996 National Hospital Ambulatory Medical Care Survey. Antibiotic prescribing rates were examined for colds, upper respiratory tract infections, and acute bronchitis. Patients with comorbid conditions or secondary diagnoses, such as chronic obstructive pulmonary disease, pneumonia, sinusitis, and HIV, were excluded. Bivariate and multivariate analyses were used to assess predictors of antibiotic use. Results: Overall, there were an estimated 2.7 million ED visits for colds, upper respiratory tract infections, and bronchitis by children and adults in 1996. Antibiotics were prescribed for 24.2% (95% CI 18.9, 29.5) of patients with common colds and upper respiratory tract infections and for 42.2% (95% CI 35.2, 49.2) of patients with bronchitis. There were no significant associations between antibiotic use and patient race, sex, Hispanic ethnicity, geographic location, or source of payment. Antibiotics were prescribed less often by interns or residents than by staff or other physicians (odds ratio 0.43; 95% CI 0.19, 0.98), and patients younger than 18 years were less likely to receive antibiotics than adults (odds ratio 0.32; 95% CI 0.20, 0.52). Smokers were 4.3 (95% CI 2.2, 8.3) times more likely to receive antibiotics than nonsmokers. Conclusion: Antibiotics are commonly prescribed for ED patients with upper respiratory tract infections even though they are usually ineffective in otherwise healthy adults. Efforts should be made to reduce inappropriate antibiotic use for the sake of containing costs, preventing side effects, and limiting the spread of antibiotic resistance. [Stone S, Gonzales R, Maselli J, Lowenstein SR. Antibiotic prescribing for patients with colds, upper respiratory tract infections, and bronchitis: a national study of hospital-based emergency departments. Ann Emerg Med. October 2000;36:320-327.]

Introduction

By and large, infection has become a relatively minor threat to life, as we have civilized ourselves and installed plumbing and even less a threat now that we have antibiotics.¹ The spread of antibiotic-resistant bacteria is an important problem in medicine and in public health.2, 3, 4, 5, 6, 7, 8, 9 Before the mid 1980s, virtually all strains of Streptococcus pneumoniae in the United States were sensitive to penicillin. However, over the past 15 years the Centers for Disease Control and Prevention has detected a 60-fold rise in high-level resistance to penicillin.¹⁰ Today, in some areas of the United States, more than 30% of invasive isolates of S pneumoniae demonstrate intermediate- or high-level resistance to penicillin.11, 12, 13 Often, penicillin-resistant strains are also resistant to other antibiotics, including macrolides, trimethoprim-sulfamethoxazole, and second- and third-generation cephalosporins.10, 14, 15, 16

Drug-resistant strains of S pneumoniae have attracted considerable attention, because this organism is responsible for common, often lethal infections, such as meningitis, pneumonia, and bacteremia.5, 10 At the same time, antibiotic resistance is growing among other pathogens, including Streptococcus pyogenes, Haemophilus influenzae, enterococci, staphylococci, Neisseria gonorrhoeae, Salmonella, Mycobacterium tuberculosis, and Escherichia coli and other urinary pathogens.7, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24

The spread of antibiotic resistance is multifactorial. Bacteria acquire resistance naturally, through genetic mutations and through the exchange of genetic material among microorganisms.7, 14, 25, 26 However, it is under the selective pressure of frequent antibiotic use that resistant strains are encouraged to multiply and spread rapidly.¹⁰ Indeed, one of the most consistent risk factors for the carriage of and infection with drug-resistant S pneumoniae is recent antibiotic use.2, 3, 4, 10, 27, 28, 29, 30, 31 Several studies have demonstrated a direct association between recent antibiotic use in the outpatient setting (at least 1 course of antibiotics within 2 months) and nasopharyngeal colonization with drug-resistant S pneumoniae. Recent antibiotic use is also an independent risk factor for invasive infections caused by drug-resistant S pneumoniae.27, 28, 29, 30

Reducing unnecessary antibiotic use is a critical step in any effort to decrease the prevalence of antibiotic-resistant S pneumoniae.5, 10, 27, 30, 31, 32, 33, 34, 35 Of special concern is the overuse of antibiotics for routine colds, upper respiratory tract infections (URIs), and acute bronchitis. In almost all cases, these are viral, self-limited conditions that do not benefit from antibiotic use.34, 35, 36, 37, 38, 39, 40, 41 Nevertheless, antibiotics are commonly prescribed. According to the National Ambulatory Medical Care Survey (NAMCS), a statistical sample of records from physicians’ offices, 31% of all outpatient antibiotic prescriptions were for colds, URIs, or bronchitis.⁴² In a subsequent analysis of the NAMCS data, Gonzales et al³³ found that antibiotics were prescribed for 51% of adult patients with colds, 52% of patients with URIs, and 66% of patients with acute bronchitis. In a study of Medicaid claims data in Kentucky, Mainous et al43, 44 reported that 60% of patients with common colds and 75% of patients with bronchitis received antibiotics.

Although recent studies have characterized antibiotic use in office-based practice, little is known about antibiotic prescribing rates in emergency departments. It is known, however, that “acute upper respiratory tract infection excluding pharyngitis” is the leading illness-related diagnosis during ED visits.⁴⁵ In 1997, antibiotics were the second-leading category of drugs prescribed, after analgesics; overall, antibiotics accounted for 16.8% of all ED drug mentions.⁴⁵

In this study, we used data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) to examine antibiotic prescribing patterns in EDs. We conducted this study with the following specific objectives: (1) to identify the most common conditions for which antibiotics were prescribed; (2) to measure antibiotic prescription rates for patients with common colds, URIs, and bronchitis; and (3) to determine whether patient age, sex, race, Hispanic ethnicity, smoking status, practice location, level of provider training or other variables were associated with higher rates of antibiotic use.