Dr. Thomas reported findings from a study of changes in the utilization and costs of prescription drugs in three therapeutic classes: (1) gastrointestinal disease medications, (2) antiarthritics, and (3) cholesterol-reducing medications. The study was conducted by researchers at Brandeis University and PCS Health Systems. It relied on 1996-99 prescription claims data from PCS Health Systems, a PBM, for an insured population of 1.3 million employees and their families.
The study found large increases in expenditures in all three therapeutic classes. However, the relative contribution of price and utilization differed across classes.
- Gastrointestinal disease medications. A large portion of the growth in expenditures in this category was due to increases in cost per prescription. Since the introduction of proton pump inhibitors (PPIs) (e.g., Prilosec®) in the 1990s, the cost of medication per prescription has been increasing very quickly. PPIs are much more expensive than the older H2 receptor antagonists (e.g., Cimetidine®).
- Antiarthritics. Much of the growth in expenditures in this category was due to increases in the cost per prescription. Since the market entry of Cox-2 inhibitors (e.g., Celebrex®, Vioxx®) in January 1999, the utilization of these new medications has skyrocketed. Cox-2 inhibitors are five times more expensive than traditional nonsteroidal anti-inflammatory drugs (e.g., ibuprofen).
- Cholesterol-reducing medications. The growth in expenditures in this category was due largely to increased utilization. The threshold of treatment for high cholesterol has been lowered in recent years, causing rapid growth in the number of people using statins (e.g., Lipitor®, Zocor®, and Prachol®).