Influence of urologists' practice affiliations with medical schools on the use of medical androgen deprivation therapy for prostate cancer

Research Objective:

Physician academic affiliations and changes in drug reimbursement rates have been shown to influence physician practice patterns regardless of clinical guidelines, patient clinical or sociodemographic factors. We examined the association between urologists' practice affiliations with medical schools and the utilization of medical androgen deprivation therapy (ADT) before and after reductions in medical ADT reimbursement rates resulting from the 2003 Medicare Modernization Act (MMA).

Study Design:

Multilevel regression analyses were used to evaluate the influence of urologists' practice affiliations with medical schools on primary medical ADT use on patients within 6 months of diagnosis – a treatment regimen that is at variance with clinical guidelines and has not been shown to improve survival or other patient-centered outcomes.

Population Studied:

Using the Surveillance, Epidemiology and End Results – Medicare linked database and the American Medical Association Physician Masterfile, we conducted a retrospective cohort study of 10,301 patients aged 66 years or older who were diagnosed between 2003 and 2005 with localized, low-to-intermediate grade prostate cancer, and the 1,577 urologists who saw them.

Principal Findings:

Overall, 3,763 (37%) patients received medical ADT. After adjusting for patient, tumor and urologist characteristics, patients who saw urologists with no practice affiliation with medical schools were significantly more likely to receive medical ADT (odds ratio [OR], 2.03; 95% confidence interval [95% CI], 1.57-2.63). Compared to 2003, when the MMA went into effect, the odds of receiving medical ADT were significantly lower in 2004 (OR, 0.76; 95% CI, 0.68-0.85) and 2005 (OR, 0.51; 95% CI, 0.45-0.57).

Conclusions:

Even though the overall odds of patients receiving unnecessary medical ADT decreased after the MMA reimbursement reduction, urologists without practice affiliations with medical schools were still significantly more likely to prescribe medical ADT; such treatment patterns are not consistent with patient-centered clinical guidelines and unlikely to have significant survival benefit.

Implications for Policy, Delivery and Practice:

The significant associations found in this study between urologists' practice affiliations with medical schools and the utilization of medical ADT provides further insights into what efforts may be successful in reducing overtreatment of localized prostate cancer patients with primary medical ADT following Medicare reimbursement reductions. This study also provides additional evidence for clinicians and policy makers regarding factors including, physician reimbursement, that may influence adherence to evidence-based guidelines.