A few people asked me about the data, so here’s a link to the original scientific paper: Shrank WH, et al, “The Epidemiology of Prescriptions Abandoned at the Pharmacy,” Annals of Internal Medicine, November 2010.
As far as I know, this article is the best publicly-available, peer-reviewed analysis of how co-payment levels influence whether a patient actually picks up a prescription. Lots-o'-Data in the original article, but read on for a few highlights along with a strawberry-scented chart.
The Annals study analyzes 10.3 million prescriptions filled by 5.2 million people over a 3-month period in 2008. All data came from CVS Caremark (NYSE:CVS) by matching CVS retail transactional activity to Caremark claims data. (I don’t consider this factor to be material in interpreting the results.) Full details of the methodology are described in the paper.
Prescriptions were classified into three mutually exclusive outcomes:
- Filled prescription, indicating that the patient purchased the prescription;
- Return-to-Stock (RTS), indicating that the patient abandoned the prescription; or
- RTS with fill, indicating that the patient abandoned the prescription and it was returned to stock, but the patient purchased a prescription for a medication in the same medication class at the same or another pharmacy.
The overall abandonment rate was 3.27%, comprised of 1.77% RTS (outcome #2) and 1.50% RTS with fill (outcome #3).
Table 3 (page 637) relates various factors to the relative risk of prescription abandonment. Here’s my visual summary of the bivariate relationship between the patient’s out-of-pocket costs and prescription abandonment rates (outcome #2 above).
As you can see, co-pays above $20 seem to be the tipping point for people who decide not to fill their scripts. Amazingly, even a co-pay of $0.00 (824K prescriptions) had an abandonment rate of 1.5%!
Table 2 (page 636) has useful data on abandonment by medication class.
- Opiates and antiplatelet medications were least likely to be RTS prescriptions (1.0% and 0.9%, respectively) or RTS with fill (0.8% and 1.1%). Antihypertensives, oral diabetic medications, and statins also had comparatively low abandonment rates.
- Among daily-use therapies, higher rates of RTS were seen for proton-pump inhibitors (2.6%), asthma medications (3.5%), and insulin (2.2%).
- Medications used on an as-needed basis, such as dermatologic agents (RTS rate, 2.9%) and cough and cold medications (RTS rate, 3.6%) were also abandoned more commonly.