Antibiotic Prescribing in Ambulatory Settings without a Documented Indication Jessina C. McGregor, PhD; Miriam R. Elman, MPH; David T. Bearden, PharmD Oregon State University/Oregon Health & Science University College of Pharmacy Abstract (updated) Background: Retrospective review of antimicrobial prescribing depends upon adequate documentation of the indication for therapy. We sought to evaluate the prevalence of antibiotic prescribing in the absence of a documented indication using nationally representative data from the ambulatory setting. Methods: We used data from the 2009 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, which represent over 1.2 billion ambulatory visits in emergency, hospital, and clinic-based ambulatory settings. Among patients with an antibiotic prescription, we identified the proportion without an ICD-9 diagnosis code for a bacterial infection or possible bacterial infection. We compared this proportion across ambulatory settings and patient age groups (chi-square test). Patients without a clear indication for an antibiotic were further characterized by diagnoses and antibiotics prescribed. Results: Antibiotics were prescribed in 158,615,007 (12.5%) of U.S. ambulatory visits in 2009. Of these, 54,197,236 (34.2%) had no documented diagnosis of a bacterial infection. Patients over 64 years old were significantly more likely (p<0.01) to be prescribed an antibiotic in absence of a clear indication compared to pediatric patients and younger adults; however, prescribing did not vary by clinical setting (p=0.76). A documented indication was absence in 22.6%, 20.2%, 15.1%, 10.5% and 9.8% of visits with a cephalosporin, quinolone, penicillin, sulfonamide, and macrolide prescription, respectively. Conclusion: While patients without documentation of a bacterial infection may have other valid indications for antibiotic therapy (e.g., prophylactic use), there remains a large proportion of ambulatory visits in which antibiotic use may be unwarranted. While further study is needed to ensure the validity of these findings, a documented indication for antibiotic prescribing is critical for promoting prudent antibiotic use in this setting. Results Figure 2. Primary diagnosis for visits without documented indication for an antibiotic Primary Diagnosis Category % Infectious & Parasitic Diseases (Non-bacterial) 3.0 Neoplasms 3.8 Endocrine, Nutritional and Metabolic Diseases & Immunity Disorders 3.6 Diseases of Blood & Blood-Forming Organs 0.7 Mental Disorders 1.8 Diseases of Nervous System & Sense Organs 3.2 Diseases of Circulatory System 6.6 Diseases of Respiratory System 6.9 Diseases of Digestive System 7.6 Diseases of Genitourinary System 4.6 Complications of Pregnancy, Childbirth & Puerperium 0.3 Diseases of Skin & Subcutaneous Tissue 8.1 Diseases of Musculoskeletal System & Connective Tissue 5.7 Congenital Anomalies 0.9 Certain Conditions Originating in Perinatal Period 0.0 Symptoms, Signs, & Ill-Defined Conditions 14.0 Injury & Poisoning 12.4 V Codes 13.9 Other/blank* An indication was absent in 34.2% of ambulatory visits in the U.S. that had an antibiotic prescription Table 1 describes visits with an antibiotic prescription. Absence of a documented indication was Significantly higher in males and adults over 64 years (both p≤0.01) Significantly lower in patients paying with private insurance (p<0.01) Presence of an indication did not differ by race, ethnicity, setting type, or region (p=0.14, p=0.36, p=0.76, and p=0.98, respectively) Table 2 lists the primary diagnosis categories of visits without an indicated antibiotic Symptoms, Signs, Ill-defined conditions; V codes; & Injury codes were most frequent Figure 1 displays the most common antibiotic classes prescribed without documented indication Cephalosporins, quinolones, penicillins & sulfonamides each represent over 10% of visits Table 1. Characteristics of visits with an antibiotic prescription* Indication No Indication Characteristic % Sex* Female 67.5 32.5 Male 63.5 36.5 Age group* Under 18 years 80.5 19.4 18 – 64 years 62.3 37.7 65 years and older 50.7 49.1 Race White only 66.9 33.1 Black/African American only 59.7 40.3 Asian/Pacific Islander only 62.6 37.4 More than one race 77.5 22.5 Other/missing 66.1 33.9 Ethnicity Hispanic 70.9 29.1 Not Hispanic 65.4 34.6 Missing 65.1 34.9 Setting type Physician's office 65.6 33.8 Emergency medicine department 63.8 36.0 Hospital outpatient department 34.3 Insurance type* Private 70.7 28.8 Medicaid/Medicare 59.8 40.2 Self-pay 56.0 43.9 Other 54.9 45.1 Unknown/blank 66.0 45.6 Region Northeast 65.0 35.0 Midwest 65.2 34.8 South 66.4 33.6 West Background Antibiotic stewardship efforts are expanding to increase appropriate & prudent antibiotic prescribing in ambulatory settings In some healthcare systems a documented indication is required for all antibiotic prescriptions Electronic health record alerts can be triggered by diagnosis and antibiotic combinations In the absence of a documented indication, appropriateness of antibiotic selection cannot be evaluated *Other category includes visits that were not codable, patient not seen by doctor or transferred to another facility, HMO will not authorize treatment, and no diagnoses. Figure 1. Antibiotic classes prescribed in absence of a documented indication Objective To estimate the prevalence of antibiotic prescribing in the absence of a documented indication in a nationally representative sample of US ambulatory care visits in 2009. Data Source Public-use data compiled from NAMCS and NHAMCS for 2009 Antibiotic prescriptions identified using up to 8 medications reported Grouped with Lexicon Plus® therapeutic classes (Cerner Multum, Inc) Inclusion/Exclusion Criteria Visits with an antibiotic prescription included Ophthalmic diseases and conditions excluded Statistical Analysis ICD-9 codes categorized into diagnoses for which antibiotics are indicated and not indicated Diagnoses from visits with antibiotic prescriptions aggregated and evaluated for antibiotic indication Visits without documented indication described by class of antibiotic class prescribed & primary diagnosis Analysis performed using SAS v. 9.2 Analyses accounted for complex survey design Sample weights including patient visit weights, strata, & primary sampling units applied to produce nationally representative estimates Methods *Misc. antibiotic category includes drugs categorized as miscellaneous antibiotics in the Lexicon Plus® database as well as by trimethoprim-sulfamethoxazole erythromycin-neomycin, erythromycin-sulfisoxazole, ciprofloxicin-dexamethasone. Conclusions Antibiotic prescribing without documentation of an indication may be common in ambulatory settings Patients over 64 & those without private insurance were most likely to be prescribed an antibiotic without a documented indication Our findings may be biased due to missing data or misclassification in survey response data To support prudent antibiotic prescribing, the indication for the antibiotic should be documented Further research is needed to determine if certain patients are at greater risk for inappropriate antibiotic prescribing *p≤0.01 For copy of this poster, visit us online: Or contact Jessina C. McGregor, mcgregoj@ohsu.edu