By Stan Deresinski, MD, FACP, FIDSA

Clinical Professor of Medicine, Stanford University

Dr. Deresinski reports no financial relationships relevant to this field of study.

SYNOPSIS: Approximately half of U.S. residents with health insurance filled an antibiotic prescription over a two-year period.

SOURCE: Olesen SW, MacFadden D, Grad YH. Cumulative probability of receiving an antibiotic prescription over time. N Engl J Med 2019;380:1872-1873.

Using the Truven Health MarketScan Research databases, researchers assessed the probability that enrollees comprising approximately one-fifth of the U.S. population received an antibiotic prescription filled at an outpatient pharmacy during 2011 through 2014. During those years, 100 million claims for outpatient antibiotic prescriptions were made for the 62 million enrollees in health insurance plans.

Consistent with their previous work, the researchers found that 33% of the cohort had an antibiotic prescription filled at an outpatient pharmacy during a single year. This increased to 47% over two years, 55% over three years, and 62% over four years. Females were more likely to fill an antibiotic prescription than males, as were residents of South Central region states compared to other regions (the North Central region was second, followed by the Northeast and the West.) The highest users were infants ages 0 to 2 years.

Not only was the probability of patients filling an antibiotic prescription remarkably high, reaching 47% at two years and 62% at four years, it was not homogenous throughout the enrollees. Thus, while approximately one-third filled prescriptions during any one year, another one-third never did so.

COMMENTARY

The number of prescriptions for antibiotics in the United States is remarkable, and this is especially so in the southern region. This undoubted overuse, and especially the heterogeneity of use, reminds me of something mentioned in the 2005 report of a clonal outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infections among players in the National Football League.1 Examination of the 2002 pharmacy log for the team revealed that players received an average of 2.6 antibiotic prescriptions per year — a rate 10 times higher than age- and sex-matched individuals in the general population. At the same time, while approximately 60% of players reported receiving antibiotics during their 2003 season, 40% received no antibiotic at all.

Several groups have previously demonstrated the heterogeneity of antibiotic use in the United States based on, for example, geography.2 They also found that extensive use, defined as many people receiving few prescriptions, and intense use, defined as a small number of individuals receiving many prescriptions, had different relationships to the prevalence of antibiotic resistance. Thus, they found that extensive use was associated more strongly with resistance than was intensive use, suggesting that the former could be a more effective focus of interventions.

REFERENCES

  1. Kazakova SV, Hageman JC, Matava M, et al. A clone of methicillin-resistant Staphylococcus aureus among professional football players. N Engl J Med 2005;352:468-475.
  2. Olesen SW, Barnett ML, MacFadden DR, et al. The distribution of antibiotic use and its association with antibiotic resistance. Elife 2018. doi: 10.7554/eLife.39435.