BACKGROUND: Antibiotics are often prescribed for viral respiratory infections. The goal of our study was to determine the factors associated with antibiotic prescribing for acute respiratory infections in primary care.
METHODS: We performed an observational study in 15 primary care practices in Michigan using patient and physician surveys distributed during visits for acute respiratory infections. We included patients 4 years or older presenting with symptoms of an acute respiratory infection (n=482). The main outcome measures were prescriptions of antibiotics, signs and symptoms associated with antibiotic prescribing, and clinician-reported reasons for prescribing an antibiotic.
RESULTS: We found that patients who were older than 18 years, sick for more than 14 days, and seen in urgent care clinics were more likely to receive antibiotics. Patients expected antibiotics if they perceived that the drug had helped with similar symptoms in the past. In an adjusted model, the variables significantly associated with antibiotic prescribing were physical findings of sinus tenderness (odds ratio [OR]=20.0; 95% confi-dence interval [CI], 8.3-43.2), rales/rhonchi (OR=19.9; 95% CI, 9.2-43.2), discolored nasal discharge (OR=11.7; 95% CI, 4.3-31.7), and postnasal drainage (OR=3.1; 95% CI, 1.6-6.0). The presence of clear nasal discharge on examination was negatively associated (OR=0.3; 95% CI, 0.2-0.5).
CONCLUSIONS: Several physical signs play an important role in clinicians’ decisions to prescribe antibiotics for respiratory infections. This information will be useful in designing interventions to decrease inappropriate antibiotic prescribing for upper respiratory infections.
Antibiotics are widely prescribed for acute respiratory infections (ARIs) of viral origin.1-3 ARIs include the clinical syndromes of the common cold (upper respiratory infection [URI]), acute bronchitis, pneumonia, pharyngitis, sinusitis, and otitis media. Some cases of pneumonia, pharyngitis (streptococcal), sinusitis, and otitis media are bacterial infections that may improve more rapidly with antibiotic treatment, but viruses cause most of these infections.
Because of the predominantly viral etiology of most ARIs, antibiotics are of little or no benefit,4-7 and the current widespread use of antibiotics for ARIs has significant costs. In addition to the substantial monetary costs,1 overuse of antimicrobials for ARIs has contributed to the emergence and spread of resistant bacteria. Data from Iceland suggest that community-wide consumption of antimicrobials is positively related to the nasopharyngeal carriage of penicillin-resistant pneumococci.8 And data from Finland indicate that after a nationwide reduction in the use of macrolide antibiotics for outpatient therapy, there was a significant decline in the prevalence of erythromycin-resistant group A streptococci.9
Why do physicians persist in prescribing antibiotics for ARIs of likely viral origin despite a lack of evidence of effectiveness? Two explanations are plausible. First, because of the overlapping constellations of signs and symptoms of different ARIs, physicians may have some difficulty distinguishing viral respiratory infections from those that may improve more rapidly with antibiotic treatment, such as acute sinusitis or acute bronchitis. However, there is, at best, equivocal evidence from randomized trials for a modest treatment effect of antibiotics for sinusitis and a minimal effect for bronchitis.7,10-12 Second, many patients expect an antibiotic. Most clinicians believe antibiotics present minimal risk and do not want to risk patient loyalty, so they accede to patient requests, even when an antibiotic is not indicated.13 There may be other reasons unrelated to the clinical diagnosis or patient expectation, such as physician and patient concern that the patient’s condition may worsen without an antibiotic.
Most clinicians, researchers, and public health officials agree that antibiotics are overprescribed for ARIs. However, changing clinician and patient behaviors and beliefs is difficult. Admonitions and exhortations to stop prescribing are likely to be minimally effective. Educational interventions linked to performance assessment may be most effective.14 The interventions should be targeted to change specific beliefs and to correct specific knowledge gaps of both clinicians and patients. However, the factors that trigger antibiotic prescribing are not well understood. If it is patient expectation, what factors underlie that expectation? If it is physician knowledge, what are the specific gaps? Are there other factors that trigger antibiotic prescribing?
Objective
The purpose of our study was to determine the factors associated with antibiotic prescribing for ARIs in a prospective observational study. Our hypothesis was that antibiotic prescribing could be predicted from a limited number of signs and symptoms and that patients’ expectations and clinicians’ beliefs about patient expectations for antibiotics would be among the predictors of antibiotic prescribing. Our research question was: Among patients presenting to outpatient settings with symptoms compatible with ARIs, what factors-including symptoms, signs, patient characteristics, diagnoses, patient expectations, and so forth-are associated with antibiotic prescribing?
Methods
Setting
All 15 practices of the Upper Peninsula Research Network (UPRNet), a rural family practice research network in Northern Michigan, participated in our study. In January and February 1998 we asked each clinician in an UPRNet practice to enroll at least 20 consecutive patients 4 years and older who presented to the office with symptoms of an ARI. Patients were identified and invited to participate by 31 family physicians, 3 pediatricians, 5 internists, 16 physician assistants, and 3 nurse practitioners. We instructed the clinicians and their staffs not to enroll patients with a chief complaint of pharyngitis or ear pain. We excluded from the analyses patients who had a primary or secondary diagnosis of pneumonia, pharyngitis, or otitis media, because antibiotics are currently thought to be indicated for many of those cases. We included patients with the clinical diagnoses of nonspecific URI, bronchitis, and sinusitis because of the large overlap in signs and symptoms and the lack of precision in clinical diagnosis for those 3 conditions. Also, assigning a diagnosis of bronchitis or sinusitis may legitimize the use of an antibiotic for patients whose symptoms are otherwise identical to those of patients assigned the diagnosis of URI. Patients reporting symptoms for more than 30 days were excluded.