Physician-Driven Variation in Nonrecommended Services Among Older Adults Diagnosed With Cancer.

IMPORTANCE: Interventions to address overuse of health care services may help reduce costs and improve care. Understanding physician-level variation and behavior patterns can inform such interventions.
OBJECTIVE: To assess patterns of physician ordering of services that tend to be overused in the treatment of patients with cancer. We hypothesized that physicians exhibit consistent behavior. DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of patients 66 years and older diagnosed with cancer between 2004 and 2011, using population-based Surveillance, Epidemiology, and End Results (SEER)-Medicare data to assess physician-level variation in 5 nonrecommended services. Services included imaging for staging and surveillance in low-risk disease, intensity-modulated radiation therapy (IMRT) after breast-conserving surgery, and extended fractionation schemes for palliation of bone metastases. MAIN OUTCOME AND MEASURES: To assess variation in service use between physicians, we used a random effects model and a logistic regression model with a lag variable to assess whether a physician's use of a service for a prior patient predicts subsequent service use.
RESULTS: Cohorts ranged from 3464 to 89 006 patients. The total proportion of patients receiving each service varied from 14% for imaging in staging early breast cancer to 41% in early prostate cancer. From the random effects analysis, we found significant unexplained variation in service use between physicians (P < .001 for each service; ICC, 0.04-0.59). Controlling for case mix, whether a physician ordered a service for the prior patient was highly predictive of service use, with adjusted odds ratios (aORs) ranging from 1.12 (95% CI, 1.07-1.18) for surveillance imaging for patients with breast cancer (28% service use if prior patient had imaging vs 25% if not), to 24.91 (95% CI, 22.86-27.15) for IMRT for whole breast radiotherapy (69% vs 7%, respectively). CONCLUSIONS AND RELEVANCE: Physicians' utilization of nonrecommended services that tend to be overused exhibit patterns that suggest consistent behavior more than personalized patient care decisions. Reducing overuse may require understanding cognitive drivers of repetitive inappropriate decisions.