Diffusion of Bevacizumab Across Oncology Practices: An Observational Study


Nancy L Keating, Haiden A Huskamp, Deborah Schrag, John M McWilliams, Barbara J McNeil, Bruce E Landon, Michael E Chernew, and Sharon-Lise T Normand. 2018. “Diffusion of Bevacizumab Across Oncology Practices: An Observational Study.” Med Care, 56, 1, Pp. 69-77.


BACKGROUND: Technological advances can improve care and outcomes but are a primary driver of health care spending growth. Understanding diffusion and use of new oncology therapies is important, given substantial increases in prices and spending on such treatments. OBJECTIVES: Examine diffusion of bevacizumab, a novel (in 2004) and high-priced biologic cancer therapy, among US oncology practices during 2005-2012 and assess variation in use across practices. RESEARCH DESIGN: Population-based observational study. SETTING: A total of 2329 US practices providing cancer chemotherapy. PARTICIPANTS: Random 20% sample of 236,304 Medicare fee-for-service beneficiaries aged above 65 years in 2004-2012 undergoing infused chemotherapy for cancer. MEASURES: Diffusion of bevacizumab (cumulative time to first use and 10% use) in practices, variation in use across practices overall and by higher versus lower-value use. We used hierarchical models with practice random effects to estimate the between-practice variation in the probability of receiving bevacizumab and to identify factors associated with use. RESULTS: We observed relatively rapid diffusion of bevacizumab, particularly in independent practices and larger versus smaller practices. We observed substantial variation in use; the adjusted odds ratio (95% confidence interval) of bevacizumab use was 2.90 higher (2.73-3.08) for practices 1 SD above versus one standard deviation below the mean. Variation was less for higher-value [odds ratio=2.72 (2.56-2.89)] than lower-value uses [odds ratio=3.61 (3.21-4.06)]. CONCLUSIONS: Use of bevacizumab varied widely across oncology practices, particularly for lower-value indications. These findings suggest that interventions targeted to practices have potential for decreasing low-value use of high-cost cancer therapies.