Elliott, Sean Patrick, MD.2011-07-122011-07-122011-05https://hdl.handle.net/11299/109038University of Minnesota M.S. thesis. May 2011. Major: Health services research, policy, and administration. Advisor: Beth A. Virnig, M.P.H., Ph.D., 1 computer file (PDF); vi, 30 pages, appendix p. 28-30.Background Use of androgen suppression therapy (AST) in prostate cancer increased more than three-fold from 1991–1999. The 2003 Medicare Modernization Act reduced reimbursements for AST by 64% between 2004 and 2005, but the effect of this large reduction on use of AST is unknown. Methods A cohort of 72 818 men diagnosed with prostate cancer in 1992-2005 was identified from the Surveillance, Epidemiology, and End Results database. From Medicare claims data, indicated AST was defined as 3 months or more of AST in the first year in men with metastatic disease (n = 8030). Non-indicated AST was defined as AST given without other therapies such as radical prostatectomy or radiation in men with low risk disease ( n = 64 788). The unadjusted annual proportion of men receiving AST was plotted against the median Medicare AST reimbursement. A multivariate model was used to estimate the odds of AST use in men with low risk and metastatic disease, with the predictor of interest being the calendar year of the payment change. Covariates in the model included age in 5 year categories, clinical tumor stage (T1-4), WHO grade (1-3, unknown), Charlson comormidity (0,1,2,≥3), race, education, income, and tumor registry site, all as categorical variables. The models included variations in the definition of AST use (≥1, ≥3 and ≥6 months of AST). All statistical tests were two-sided. Results AST use in the low risk group peaked at 10.2% in 2003, then declined to 7.1% in 2004 and 6.1% in 2005. After adjusting for tumor and demographic covariates, the odds of receiving non-indicated primary AST decreased statistically significantly in 2004 (odds ratio (OR) = 0.70, 95% confidence interval (CI) = 0.61 to 0.80) and 2005 (OR = 0.61, 95% CI = 0.53 to 0.71) compared with 2003. AST use in the metastatic disease group was stable at 60% during the payment change, and the adjusted odds ratio (OR) of receiving AST in this group was unchanged in 2004-5. Conclusions In this example of hormone therapy for prostate cancer, decreased physician reimbursement was associated with a reduction in overtreatment without a reduction in needed services.en-USHealth services research, policy, and administrationThesis or Dissertation