Phantom Prescribing: Examining the Frequency of Antimicrobial Prescriptions Without a Patient Visit

Abstract

Objective To investigate the scale of antimicrobial prescribing without a corresponding visit, and to compare the attributes of patients who received antimicrobials with a corresponding visit to those who did not have a visit. Design Retrospective cohort Methods We followed 185,010 Medicare patients for one year after an acute myocardial infarction. For each antimicrobial prescribed, we determined if the patient had an inpatient, outpatient or provider claim in the 7 days prior to the antimicrobial prescription being filled. We compared the proportions of patient characteristics for those prescriptions associated with a visit and without a visit (i.e., phantom prescriptions). We also compared the rates at which different antimicrobials were prescribed without a visit. Results We found that of 356,545 antimicrobial prescriptions, 14.75% had no evidence of a visit in the week prior to the prescription being filled. A higher percentage of patients without a visit were identified as white (p<0.001) and female (p<0.001). Patients without a visit had a higher likelihood of survival and fewer additional cardiac events (AMI, cardiac arrest, stroke, all p<0.001). Among the antimicrobials considered, amoxicillin, penicillin, and agents containing trimethoprim and methenamine were much more likely to be prescribed without a visit. In contrast, levofloxacin, metronidazole, moxifoxacin, vancomycin, and cefdinir were much less likely to be prescribed without a visit. Conclusions Among this cohort of patients with chronic conditions, phantom prescriptions of antimicrobials are relatively common and occurred more frequently among those patients who were relatively healthy.

Prevalence of Inappropriate Antibiotic Prescribing in Primary Care Clinics within a Veterans Affairs Health Care System

“…Second, approximately one-third of antibiotic prescriptions were generated by non-face-to-face encounters, which typically lack an associated code. Our rate of such "phantom" prescribing was greater than the ϳ15% rate estimated in a study of Medicare patients with recent myocardial infarction (19), suggesting that it may be fruitful for stewardship programs to address such practices. To ascertain a true estimate of antibiotic utilization, centers may find greater benefit in reviewing lists of all antibiotics prescribed, as was done here, rather than focusing exclusively on infectionassociated diagnosis codes.…”

Trends in outpatient antibiotic prescribing practice among US older adults, 2011-2015: an observational study

“…27 Second, pharmacy claims data do not contain information about the condition the drug is intended to treat, so our matching of encounters and prescriptions may have measurement bias or be affected by trends in coding practice. 28,29 In addition, we were not able to classify approximately 18% of antibiotic claims as appropriate or inappropriate because they had no associated diagnoses, similar to a previous study 30 that found that 15% of Medicare antibiotic claims had no associated encounter. Third, the 5-year period of our study prevents assessment of…”

Probabilistic pairwise model comparisons based on discrepancy measures and a reconceptualization of the p-value

“…This will occur even when the distribution of the data is approximately bell-shaped. In another example of accurate estimation leading to a small p-value, Riedle et al (2017) show that the odds of a patient over 85 years of age receiving an antimicrobial prescription without a corresponding visit to a clinician is only 1.055 (95% CI : (1.023, 1.088)) times the odds for a patient under 85, yet the p-value is 0.0007. Because this odds ratio is accurately estimated, then a fairly modest effect is able to reach a high level of statistical significance.…”

“…Our second application seeks to determine whether white patients who are prescribed antimicrobials are more likely to receive the prescription without a corresponding physician visit. This application is based on results from Riedle et al (2017). Antimicrobial resistance is a major public health concern.…”

“…phantom prescriptions) traditional approaches designed to ensure proper prescribing may not be effective. Therefore, one important aspect of the Riedle et al (2017) study is to determine important predictors of whether a prescription was filled without a corresponding visit. For this application, we specifically seek to determine whether white patients are more likely to receive at least one phantom antimicrobial prescription.…”