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Appropriateness of outpatient antibiotic prescribing among privately insured US patients: ICD-10-CM based cross sectional study

BMJ 2019; 364 doi: (Published 16 January 2019) Cite this as: BMJ 2019;364:k5092

Linked opinion

The challenges of developing healthcare quality measures based on ICD-10-CM codes

Re: Appropriateness of outpatient antibiotic prescribing among privately insured US patients: ICD-10-CM based cross sectional study

There would seem to be two take-home messages:
(1) The proportion of antibiotic use that seems clearly justified without further inquiry is about 1 in 8, which seems reasonably in line with field experience.
(2) The results overestimate appropriate antibiotic use.

One question is coding accuracy, which the authors point out could be affected by the decision to prescribe antibiotics. From my experience (ie, reviewing thousands of records during routine care, with a stewardship point of view, also having the patient to interview and re-examine), misdiagnosis is a larger concern than miscoding. Another question is just how often are antibiotics realistically helpful when possibly indicated. How might code counts and classifications be inflated for the “top 3” always/potentially appropriate diagnoses:

Urinary tract infection
– Occasionally misdiagnosed.
– Many mild cases would resolve without antibiotics (I believe the 2018 NICE guideline [1] is the first daring to suggest back-up instead of immediate antibiotics).

Streptococcal pharyngitis
– Often misdiagnosed (presumed without testing; rapid antigen test used too soon after resolved GAS pharyngitis; viral pharyngitis in GAS carrier; no pharyngitis but GAS testing to investigate cough…).
– Necessity of antibiotics debatable; several European guidelines (eg, 2–3) do not recommend reflex antibiotics.

Bacterial pneumonia
– Misdiagnosis not rare (on the other hand, some “bronchitis” and even occasional “URTI” are also pneumonia).
– Future opportunities for reducing antibiotic use, but stuck with routine use for now…

Acute sinusitis
– Frequently misdiagnosed; code implies presumed bacterial sinusitis, but typically disease consistent with sinonasal symptoms of the common cold (or sometimes noninfectious symptoms); imaging overused and misinterpreted.
– If we accept the NNTB estimates from meta-analyses (eg, 4–6) of about 10 to 20 in mild sinusitis, this means benefit for only 5 to 10% of patients (severe sinusitis is relatively rare), so antibiotic use should be thoughtful.

Acute suppurative otitis media
– Frequently misdiagnosed; typically redness of tympanic membrane without findings of suppurative OM. Routinely see patients with AOM diagnosed within last few days and completely normal otoscopy.
– Impact of antibiotics seems similar to sinusitis in most cases (7).

Acute pharyngitis
– Classifying this as potentially appropriate could be overly generous.

Both “appropriate” categories should overestimate (1) cases where antibiotic prescription can be reasonable (eg, conforms to guidelines); (2) cases where the patient in fact benefits; and (3) cases where antibiotics are actually *necessary* to get better (which may be a thing once drug resistance is sufficiently disastrous).

Studies on the reliability of coding in routine care are clearly needed, but chart review seems challenging as necessary information is so often missing. It’s not helpful when the record says “otitis on the right” since you can’t know what that means, excluding vague records would bias results, and keeping them would leave a large number of ambivalent cases once again.

In conclusion, antibiotic use remains a public health disaster — “this is why we can’t have nice things”.

(1) Urinary tract infection (lower): antimicrobial prescribing. NICE guideline [NG109]. London: NICE, 2018. url:
(2) Pelucchi C et al. ESCMID guideline for the management of acute sore throat. Clin Microbiol Infect. 2012. doi: 10.1111/j.1469-0691.2012.03766.x.
(3) Sore throat (acute): antimicrobial prescribing. NICE guideline [NG84]. London: NICE, 2018. url:
(4) Lemiengre MB et al. Antibiotics for acute rhinosinusitis in adults. Cochrane Database Syst Rev. 2018. doi: 10.1002/14651858.CD006089.pub5.
(5) Young J et al. Antibiotics for adults with clinically diagnosed acute rhinosinusitis: a meta-analysis of individual patient data. Lancet. 2008. doi: 10.1016/S0140-6736(08)60416-X.
(6) Falagas ME et al. Comparison of antibiotics with placebo for treatment of acute sinusitis: a meta-analysis of randomised controlled trials. Lancet Infect Dis. 2008. doi: 10.1016/S1473-3099(08)70202-0.
(7) Venekamp RP et al. Antibiotics for acute middle ear infection (acute otitis media) in children. Cochrane Database Syst Rev. 2015. doi: 10.1002/14651858.CD000219.pub4.

Competing interests: No competing interests

20 January 2019
Jussi M J Mustonen
General practitioner
Occupational Health Helsinki
PO Box 5600, 00099 City of Helsinki