The substantial decrease in the use of LHRH agonists in the U.S. since 2004 may not be entirely explained by a recent reduction in physician reimbursement.
The study of LHRH agonist use in the U.S., presented at the AUA annual meeting by Steven L. Chang, MD, a urologic oncology fellow at Stanford, evaluated the annual claims for LHRH agonists from 2003 to 2007 in two different health care systems: Medicare and the Veterans Health Administration. Between 2004 and 2005, the Medicare Modernization Act (MMA) was phased in, dramatically decreasing physician reimbursement for LHRH agonists in the Medicare health care system. However, the act had no impact in the VA health care system, where physicians are salaried.
Dr. Chang and his collaborators collected claims data from the Centers for Medicare & Medicaid Services from 2004 to 2007. They found that after the MMA was enacted, the average reimbursement for LHRH agonist claims fell dramatically by 54.8%, from $343 to $155. This reduction in physician reimbursement was associated with a 25.1% decline in annual claims, from 2.5 million to 1.8 million claims.
"We originally expected that LHRH agonist usage would remain stable or continue to trend upward in the VA population, given the fact that the MMA had no impact on the VA health care system. Much to our surprise, there was a strikingly similar decline in LHRH agonist utilization in both health care systems after the MMA was enacted," said Dr. Chang, who worked on the study with Rajesh Shinghal, MD, and Joseph C. Liao, MD.
"With a 16.8% drop [in LHRH agonist use] in the VA population and a 25.1% drop in the Medicare population, there's only a difference of 8.3% between the two health care systems, leading us to conclude that reimbursement is not the only factor in the decreasing utilization of LHRH agonists in the U.S. There must be competing factors independent of financial motivation that are causing physicians to change their practice patterns."
What influences treatment patterns?
During his presentation, Dr. Chang noted that a possible reason for the decreased use of LHRH agonists may be the growing concern about their adverse effects, such as impaired sexual function, decreased bone density, metabolic syndrome, and cardiovascular morbidity.
"It is certainly possible that the increasing awareness of these effects has led physicians to develop a more discriminating attitude toward initiating and continuing androgen deprivation therapy in recent years," Dr. Chang suggested.
"Intermittent androgen deprivation therapy has grown in popularity over the past several years, as numerous studies have shown that overall survival benefits seen with intermittent therapy are similar to those seen with continuous therapy, but with improved quality of life. As more physicians elect to use intermittent therapy, the overall use of LHRH agonists would decrease even if the number of patients on androgen deprivation therapy were to remain stable."
The possibility that a decline in pharmacologic castration might have been compensated for by a rise in simple orchiectomies was dismissed when Medicare data showed a 24% decline, rather than an increase, in claims for the surgical procedure during the course of the study in the Medicare population.
"We found no compensatory increase in the number of simple bilateral orchiectomies to explain the downward trend in LHRH agonist use," said Dr. Chang.
"The main finding of our study is that the decrease in the utilization of LHRH agonists in the United States is not driven solely by reimbursement changes. Changing practice patterns by physicians in both the Medicare and VA health care systems is more likely a result of multiple factors."
The investigative group plans to continue research to further clarify the impact of the various potential motivations on the use of LHRH agonists.