Research

Prescription Drug Atlas

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Contents

Executive Summary
Authors: Brenda Motheral, PhD; Emily R. Cox, PhD; Doug Mager, BS; Rochelle Henderson, MPA; Ruth Martinez, RPh

The authors would like to thank the following people for their feedback on the Atlas: Kathleen Fairman, MA; Raulo Frear, PharmD; Catherine Roe, PhD; Edward Spitznagel, PhD; Fred Teitelbaum, PhD

It has been known for some time that, when it comes to the use of prescription medications, two basic truths hold. First, the older you get, the more medication you use. Second, women consume more prescription medications on average than men do. For the first time, Express Scripts presents national data that suggests a third contributing factor: geographic location.

This study analyzed prescription claims from Express Scripts members to investigate questions such as:

  • Which regions of the United States have the greatest use of prescription medications?
  • Do regional patterns of prescription use vary by therapeutic category?
  • Which therapeutic categories exhibit the greatest variation in use?
  • What are possible reasons for any observed variation in prescription use?

Prescription use was tracked for a random sample of commercially insured Express Scripts members who were continuously enrolled for the entire year of 2000. Findings are reported separately for adults (aged 18 to 64 years) and children (infants to age 17). The final sample sizes for adults and children were 527,512 and 194,538, respectively. More than 700 different client groups were represented in the sample.

For the purpose of this study, a "user" was defined as a member who had at least one prescription claim during the calendar year 2000. "Prescription" referred to both new and refill prescription claims. All rates were adjusted for age and sex using the direct standardization method.

In addition to an evaluation of overall prescription use for adults, we also present findings on geographic variations in the prevalence of use for 23 of the most commonly prescribed therapy categories. Among children, four of the most commonly used therapeutic categories were studied. Given previous evidence of geographic variation in the use of stimulant medications for treating of attention deficit hyperactivity disorder (ADHD) among school-aged children, stimulant use among children aged 5 to 14 was examined.

For each therapeutic category, variations in drug use across states were calculated using three statistics: the Weighted Coefficient of Variation, the Systematic Component of Variation, and the Interquartile Ratio.

Geographic Patterns of Use Among Adults and Children
  • Overall, roughly 67% of all adult beneficiaries consumed at least one prescription during 2000. The percentage varied from a high of 71% to a low of 58%.
  • The mean number of prescriptions per member per year showed a 1.5-fold variation, from 8.3 to 12.2, with lower use in the Northeast and West and higher use in the South and Midwest.
  • Regional patterns of use varied by therapy class. For example, use of gastrointestinal drugs was greatest in the South, while antiasthmatic use was lower in the South. Estrogen use was lowest in the Northeast.
  • For children, the overall prevalence of use varied across states from a high of 64% to a low of 48%.
  • Among children, overall use was higher in the Midwest and West South Central and lower in the West.
  • Children's stimulant use ranged from a high of 6.5% to a low of 1.9%. The highest use occurred in the South followed by the Midwest. Use was lowest in the West and Northeast.
Variation by Therapeutic Category
  • Among adults, the greatest variations in the use of chronic medications were seen for calcium channel blockers, diuretics, and estrogen medications, while the smallest variations occurred with antihyperlipidemics and beta blockers.
  • For non-chronic classes, the greatest variations were observed for cough/cold/allergy, corticosteroids, and antihistamines. Ophthalmics, penicillins and macrolides showed the least amount of variability across states for adults.
  • The therapy categories with the greatest variation among children were cough/cold/allergy products and stimulant medications. The least geographic variation was observed for penicillins.

Discussion
One of the first questions that stem from this research is "Why do these variations occur?" Several factors, including underlying prevalence of disease, variation in physician prescribing behavior, and patient preferences, may play a role in explaining variation in prescription use. For example, findings on diabetes and cardiovascular disease indicate that the observed variation in drug use is correlated with disease prevalence by state. Furthermore, our findings provide support for the physician practice style hypothesis because variations were higher for conditions in which greater uncertainty exists regarding diagnosis and treatment, including the calcium channel blockers and estrogen replacement medications. However, both potential explanations warrant further examination.

A second question that logically follows is, "Which rate is right?" Is over-prescribing a problem in the highest use areas, or is underuse occurring in the lowest use areas? While this study was not designed to provide definitive answers to this question, we expect that a combination of over- and under-use is occurring, depending on the therapeutic category and region of the country. This is an important and exciting area of research that Express Scripts is exploring.

Implications
Plan sponsors and third-party administrators must stay one step ahead of the game as they are faced with unprecedented prescription cost growth resulting from increased utilization, price inflation, and new product introductions. These pressures, together with growing consumerism that is fueled in part by direct-to-consumer advertising, make the task of managing a pharmacy benefit a complex mission. Express Scripts helps guide our clients through this increasingly complicated pharmacy landscape by multiple initiatives - the Prescription Drug Atlas being the most recent.

The Express Scripts Prescription Drug Atlas serves two important purposes. First, its data provides benchmarks for plan sponsors and third-party administrators to use in understanding utilization patterns within their patient population and region of the country. Second, it highlights the need for further efforts to identify the underlying reasons for variation in prescription use and the appropriateness of prescription use across geographic regions. Considering the risk to patients who take medications unnecessarily, the associated waste of resources, and the implications of undiagnosed and untreated conditions, ensuring appropriate use of medications is an essential focus. To that end, Express Scripts is committed to improving the extent to which pharmaceuticals are being used in the safest, most effective, and most cost-effective manner.

 

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