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Antibiotic prescribing without documented indication in ambulatory care clinics: national cross sectional study

BMJ 2019; 367 doi: (Published 11 December 2019) Cite this as: BMJ 2019;367:l6461

Linked Editorial

Coding infections in primary care

  1. Michael J Ray, doctoral student, researcher12,
  2. Gregory B Tallman, assistant professor3,
  3. David T Bearden, clinical professor2,
  4. Miriam R Elman, biostatistician1,
  5. Jessina C McGregor, associate professor2
  1. 1Oregon Health & Science University-Portland State University School of Public Health, Portland, OR 97239, USA
  2. 2Oregon State University College of Pharmacy, Portland, OR 97201, USA
  3. 3Pacific University School of Pharmacy, Hillsboro, OR 97123, USA
  1. Correspondence to: M J Ray raymi{at} (or @MichaelRayMPH on Twitter)
  • Accepted 6 November 2019


Objectives To identify the frequency with which antibiotics are prescribed in the absence of a documented indication in the ambulatory care setting, to quantify the potential effect on assessments of appropriateness of antibiotics, and to understand patient, provider, and visit level characteristics associated with antibiotic prescribing without a documented indication.

Design Cross sectional study.

Setting 2015 National Ambulatory Medical Care Survey.

Participants 28 332 sample visits representing 990.9 million ambulatory care visits nationwide.

Main outcome measures Overall antibiotic prescribing and whether each antibiotic prescription was accompanied by appropriate, inappropriate, or no documented indication as identified through ICD-9-CM (international classification of diseases, 9th revision, clinical modification) codes. Survey weighted multivariable logistic regression was used to evaluate potential risk factors for receipt of an antibiotic prescription without a documented indication.

Results Antibiotics were prescribed during 13.2% (95% confidence interval 11.6% to 13.7%) of the estimated 990.8 million ambulatory care visits in 2015. According to the criteria, 57% (52% to 62%) of the 130.5 million prescriptions were for appropriate indications, 25% (21% to 29%) were inappropriate, and 18% (15% to 22%) had no documented indication. This corresponds to an estimated 24 million prescriptions without a documented indication. Being an adult male, spending more time with the provider, and seeing a non-primary care specialist were significantly positively associated with antibiotic prescribing without an indication. Sulfonamides and urinary anti-infective agents were the antibiotic classes most likely to be prescribed without documentation.

Conclusions This nationally representative study of ambulatory visits identified a large number of prescriptions for antibiotics without a documented indication. Antibiotic prescribing in the absence of a documented indication may severely bias national estimates of appropriate antibiotic use in this setting. This study identified a wide range of factors associated with antibiotic prescribing without a documented indication, which may be useful in directing initiatives aimed at supporting better documentation.


  • Contributors: MJR and JCM designed the study. GBT and MRE assisted with data preparation and analysis. MJR analyzed and interpreted the data. JCM supervised the study. GBT and DTB provided clinical expertise. MJR drafted the manuscript. MJR, GBT, DTB, MRE, and JCM critically revised the manuscript. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted. MJR is the guarantor.

  • Funding: This was an unfunded project.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: no support from any organization for the submitted work; JCM has received grants from Merck, Agency for Health Care Research and Quality (AHRQ), and Centers for Disease Control and Prevention (CDC) outside the submitted work; MRE has received grants from the AHRQ, CDC, Society for Infectious Diseases Pharmacists, and Oregon State University outside the submitted work; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Owing to the use of publicly available data, no institutional review board approval was necessary.

  • Data sharing: The data used in this study are publicly available from the US National Center for Health Statistics

  • Transparency: The lead author (the manuscript’s guarantor) affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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