Medicare accomplished what clinical guidelines and evidence-based medicine couldn't: it reduced unnecessary use of androgen deprivation therapy (ADT) in prostate cancer.
Inappropriate use decreased by almost 30% from 2003 to 2005, following enactment of the Medicare Modernization Act, which lowered physician reimbursement for ADT. Appropriate use of ADT did not change during the same time period, according to an article in the Nov. 4 issue of the New England Journal of Medicine.
"Our findings suggest that reductions in reimbursement may influence the delivery of care in a potentially beneficial way, with even the modest [reimbursement] changes in 2004 associated with a substantial decrease in the use of inappropriate therapy," Vahakn B. Shahinian, MD, of the University of Michigan in Ann Arbor, and co-authors wrote in conclusion.
"The corollary is that reimbursement policies should be carefully considered to avoid providing incentives for care for which no clear benefit has been established. The extreme profitability of the use of gonadotropin-releasing hormone (GnRH) agonists during the 1990s probably contributed to the rapid growth in the use of ADT for indications that were not evidence-based."
Surgical or medical castration has been a mainstay of treatment for prostate cancer for years. During the 1990s, medical castration with GnRH agonists became a particularly attractive option for physicians because of Medicare's reimbursement structure, the authors noted in the introduction to their findings.
Medicare reimbursed physicians for subcutaneous or intramuscular administration of GnRH agonists at 95% of the average wholesale price. A study by the Government Accountability Office showed that physicians' cost for GnRH agonists averaged 82% of the average wholesale price.
Because of the difference between cost and reimbursement, profits from ADT accounted for as much as 40% of revenues in some private urology practices.
Following enactment of the Medicare Modernization Act in 2004, reimbursement for ADT was reduced to 85% of average wholesale price, 80% in the case of GnRH agonists. In 2005, reimbursement for ADT changed to 106% of the average retail price.
Those reimbursement changes amounted to reductions of 50% or more for administration of GnRH agonists.
"Given the drastic cuts in reimbursements, we hypothesized that the use of ADT would decline markedly for indications for which there was limited evidence of efficacy but that ADT would continue to be used for evidence-based indications," the authors wrote.
To test the hypothesis, investigators queried the NCI Surveillance, Epidemiology, and End Results database linked to Medicare. They identified 54,925 patients who had new diagnoses of locally advanced prostate cancer from 2003 through 2005, were 65 or older, and were Medicare beneficiaries for at least six months after diagnosis.
The authors separated the study population into three categories according to the strength of the indication for ADT:
- Inappropriate use -- No reasonable expectation of benefit (Stage T1-2, Gleason 2 to 6, no surgery or radiation therapy)
- Appropriate use -- Necessary on the basis of evidence of efficacy and limited alternatives (T3-4 treated with radiation therapy)
- Discretionary -- Uncertain benefit or reasonable alternatives available (T1-2, Gleason 7 to 10).
The data showed that 43.2% of the study population received ADT within six months of diagnosis during the period reviewed. The level of appropriate use did not change significantly during 2003 through 2005.
In contrast, the rate of inappropriate use declined from 38.7% in 2003 to 30.6% in 2004 to 25.7% in 2005, representing a 28% decrease in the odds for ADT use in 2005 versus 2003.
The odds ratio for discretionary use of ADT in the adjuvant or primary setting remained stable during 2003 to 2004 but declined significantly from 2004 to 2005. Comparison of 2003 and 2005 resulted in an odds ratio of 0.88 for adjuvant use of ADT and 0.85 for primary therapy.
Acknowledging alternative explanations for the findings, the authors said they could not account for a possible switch to intermittent or longer-acting formulations of ADT, which could have manifested as a decrease in use.
"These findings are consistent with previous research on the influence of financial incentives on the delivery of healthcare," the authors wrote in the discussion of their findings. "Financial incentives are most likely to have an effect on physicians' behavior in cases in which medical uncertainty exists, as opposed to cases in which care is clearly lifesaving.
"The degree of financial incentive is also important. Our results show a gradient, with the greatest drop in ADT use in the context of greatest uncertainty about efficacy and no drop in use where benefits are clearest, findings that are consistent with the hypothesis that financial incentives may be driving observed trends."
The authors stated that they had no relevant disclosures.
Zalman S. Agus, MD Emeritus Professor
University of Pennsylvania School of Medicine and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
New England Journal of MedicineSource Reference: Shahinian VB, et al "Reimbursement policy and androgen-deprivation therapy for prostate cancer" N Engl J Med. 2010 ;363: 1822-1832.