Acute respiratory tract infection: A practice examines its antibiotic prescribing habits

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Original Research

Acute respiratory tract infection: A practice examines its antibiotic prescribing habits

J Fam Pract. 2012 June;61(6):330-335

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References

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We enrolled 438 patients. Two hundred thirty-one (53%) consented prospectively to data collection with our standardized form; 207 (47%) were reviewed by retrospective chart audit. The mean age of subjects was 54 years (range 18-94, intraquartile range 45-69). Cough was the most frequent chief complaint (58%).

Statistical analysis
We calculated the frequency of each ARTI final diagnosis and its associated antibiotic prescription rate. We also tested for associations between clinical features and the provision of antibiotics. We hypothesized that our providers would be more likely to prescribe antibiotics for patients of advanced age and in the presence of other risk factors for complications.

Results

We determined patient risks for ARTI complication in the prospective data collection group only. Of the 231 patients, 147 (64%) had at least one risk for complication, the most common being age ≥65 (37%). Other risks were employment as a health care worker (12%), asthma (11%), atherosclerotic heart disease (8%), COPD (7%), and tobacco use (5%).

Final diagnoses for all patients appear in TABLE 1. We allowed clinicians to report more than one diagnosis, resulting in 501 final diagnoses reported for 438 patients (63 received 2 final diagnoses). Sinusitis was diagnosed most frequently (32%). Other common diagnoses were viral upper respiratory infection (URI) and acute bronchitis (29% and 24%, respectively).

Antibiotics most often prescribed. Three hundred four ARTI patients (69%) received antibiotic prescriptions. Macrolides were most commonly prescribed (167/304 [55%]). Two hundred eight ARTI patients (68%) received broad-spectrum antibiotics (macrolides or fluoroquinolones); 96 (32%) received narrow-spectrum agents (penicillin, cephalosporin, sulfa, or tetracycline derivatives). TABLE 2 lists the frequency of antibiotic prescription and the antibiotic class most frequently prescribed for each ARTI diagnosis.

FAST TRACK

Those who received an antibiotic had been sick, on average, for a little more than 8 days; those who didn’t receive one had been sick for 7 days.

Factors associated with increased prescribing included specific history and physical exam findings (TABLE 3). A major determinant of treatment was duration of illness. Those who received antibiotics had a mean duration of illness of 8.3 days, compared with 7.0 days for those not receiving antibiotic therapy (P = .03).

The rate of antibiotic prescribing varied by provider type (TABLE 4). Four resident physicians (all of whom were investigators) prescribed least often, followed by attending physicians, then nurse practitioners. Investigators were significantly less likely to prescribe antimicrobials than noninvestigators (P<.001). We assessed whether use of our standardized data collection form affected prescribing rates. When we excluded patients whose data were entered with this form, no difference in rates was seen.

We also noted wide ranges of prescribing rates between individual providers. While all providers enrolled patients, numbers ranged from one to 51, with a mean of 18. For those who enrolled ≥10 subjects, prescribing rates ranged from a low of 29% (8/28) for a resident physician investigator to 93% (63/68) for 4 noninvestigator attending physicians.

Factors not associated with increased prescribing. We had hypothesized that specific patient characteristics (age and medical complication) would be associated with provision of antimicrobials. However, there was no correlation between patient age and rate of prescribing. The 304 patients who received an antibiotic had a mean age of 54 years (standard deviation [SD]=18), as did the 134 who did not receive one (mean age, 54; SD=20; P=.95). There was a nonsignificant trend for a reduced rate of prescribing for patients younger than age 30. For patients 18 to 29 years old, the rate was 60% (31/52); for those ≥30 years, it was 71% (273/386; odds ratio [OR]=1.64; 95% confidence interval, 0.90-2.97).

Similarly, presence of medical complication did not significantly affect antibiotic prescribing rates. Patients with any risk factor for complication (age >65, diabetes, atherosclerotic heart disease, heart failure, COPD, asthma, tobacco smoking, or active cancer treatment) had a 62% prescription rate (91/147), which was the same as that of patients without such risks (52/84 [62%]; P=1.0).

TABLE 1
Final diagnoses for 438 patients with ARTI

Diagnosis	n (%)*
Acute sinusitis	141 (32)
Viral URI	125 (29)
Acute bronchitis	104 (24)
Asthma	31 (7)
Acute nonstrep pharyngitis	28 (6)
Pneumonia	17 (4)
COPD	14 (3)
Influenza-like illness	14 (3)
Acute otitis media	14 (3)
Strep pharyngitis	13 (3)
ARTI, acute respiratory tract infection; COPD, chronic obstructive pulmonary disease; URI, upper respiratory infection. *Percent total >100% due to 63 patients receiving 2 diagnoses and rounding

TABLE 2
Antibiotic use and type prescribed for ARTI varied by diagnosis

Diagnosis (total)	Antibiotics prescribed*	No antibiotics prescribed	Antibiotic class most frequently prescribed
Acute sinusitis (141)	139 (99%)	2 (1%)	Macrolide (53%)
Viral URI (125)	45 (36%)	80 (64%)	Macrolide (24%)
Acute bronchitis (104)	95 (91%)	9 (9%)	Macrolide (56%)
Acute nonstrep pharyngitis (28)	16 (57%)	12 (43%)	Macrolide (36%)
Pneumonia (17)	17 (100%)	0	Fluoroquinolone (53%)
ARTI, acute respiratory tract infection; URI, upper respiratory infection. *Although 304 patients received prescriptions, some patients received more than one antibiotic.