August 02, 2018, 03:13 pm News Staff – It has long been known that inappropriate antibiotic use contributes to antibiotic resistance and adverse events, such as Clostridium difficile infections. Yet even so, overuse of these medications, especially for viral respiratory infections, remains a common problem.
A research letter recently published online in JAMA Internal Medicine described its authors' efforts to determine which types of medical facilities were the biggest contributors to this problem by comparing antibiotic prescribing practices of urgent care centers, retail clinics, emergency departments (EDs) and traditional ambulatory care settings (i.e., medical offices).
The authors of this retrospective cohort study analyzed data from the 2014 Truven Health MarketScan Commercial Claims and Encounters Database, which houses claims from patients younger than age 65 who have employer-sponsored insurance.
Previous research has shown that about 60 percent of all outpatient antibiotic prescriptions dispensed in the United States are written in medical offices and EDs, with urgent care centers and retail clinics accounting for the remaining 40 percent.
The current study found that overall, clinicians in medical offices wrote the fewest antibiotic prescriptions per total number of visits (7.1 percent). The most prolific antibiotic prescribers were urgent care center clinicians, at 39 percent of total visits, followed by retail clinics (36.4 percent) and EDs (13.8 percent).
According to the researchers, visits for antibiotic-inappropriate respiratory diagnoses accounted for 17 percent of retail clinic visits, 16 percent of urgent care center visits, 6 percent of medical office visits and 5 percent of ED visits. Of these visits, antibiotics were most frequently incorrectly prescribed in urgent care centers (45.7 percent), followed by EDs (24.6 percent), medical offices (17 percent) and retail clinics (14.4 percent).
All visits included in the study occurred in 2014, with medical and prescription coverage data captured for the months before, of and after each visit (except for December 2014 visits). Visits for which no diagnosis was reported, as well as those made by patients who had recently been hospitalized or who had recent outpatient visits that included antibiotic prescriptions, were excluded.
Outpatient claims were sorted by facility codes for urgent care center, retail clinic, hospital-based ED or medical office. The unit of analysis was unique visits, and the outcome of interest was percentage of visits linked to prescription of antibiotics, stratified by setting and diagnosis.
Data on systemic (oral and parenteral) antibiotic prescriptions, identified using national drug codes from the 2016 Truven Health Red Book supplement, were extracted from outpatient pharmaceutical claims. Oral antibiotic prescriptions were linked to each enrollee's most recent outpatient visit within a three-day window; parenteral antibiotics were linked to same-day outpatient visits.
Finally, the researchers said they focused on antibiotic-inappropriate respiratory diagnoses (i.e., diagnoses where antibiotics were unnecessary according to clinical practice guidelines, such as viral upper respiratory infection, bronchitis/bronchiolitis, asthma/allergy, influenza, nonsuppurative otitis media and viral pneumonia).
The researchers found "substantial variability" among the medical settings examined for both the number of times antibiotics were prescribed per total number of visits and the number of visits made for antibiotic-inappropriate respiratory diagnoses.
"These patterns suggest differences in case mix and evidence of antibiotic overuse, especially in urgent care centers," the authors said. "This finding is important because urgent care and retail clinic markets are growing."
A previous study published May 2016 in JAMA found that an estimated 30 percent of antibiotic prescriptions written in ambulatory care settings were unnecessary.
"The finding of the present study that antibiotic prescribing for antibiotic-inappropriate respiratory diagnoses was highest in urgent care centers suggests that unnecessary antibiotic prescribing nationally in all outpatient settings may be higher than the estimated 30 percent," the researchers said.
As for limitations of the study, the authors said they include possible misclassification due to not being able to clinically validate the diagnoses listed in claims data. "These data are from a convenience sample and not generalizable to populations not captured in MarketScan," they explained.
Additionally, researchers used facility codes but couldn't validate whether facilities were actually urgent care centers, retail clinics, EDs or medical offices.
Finally, because claims data don't link antibiotics directly to visits or diagnoses, the researchers had to make assumptions about the diagnosis for which antibiotics were prescribed.
Regarding measures that could ameliorate the problem, the researchers suggested antibiotic stewardship interventions to help reduce unnecessary prescribing in all ambulatory care settings examined, paying particular attention to lowering antibiotic prescribing at urgent care centers.
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