Utilization and costs among oncologists participating in a private insurance shared savings model.

Objectives: Participation in the Oncology Care Model has influenced care utilization and costs relative to nonparticipating practices. Less is known, however, about how care is potentially altered by participation in similar private payer-based models. Here, we take advantage of a natural experiment in which 2 large practices from among a network of oncology practices participated in a shared savings program (SSP) with a private insurer.

Study design: Quasi-experimental (difference-in-differences) statistical analysis of oncology claims data.

Methods: We used monthly provider-level claims data from September 2014 through August 2017 for patients with breast, colon, and lung cancer from The US Oncology Network. Key outcome measures were monthly mean office visits, total costs, and buy-and-bill drug costs among patients with breast, colon, and lung cancer. We then compared the utilization and cost patterns, preintervention and post participation, among patients on this insurance at participating practices vs those of patients at nonparticipating practices.

Results: Monthly per-patient total costs in colon cancer and lung cancer were lower through the first year of participation in the program by $1391 (95% CI, -$2218 to -$563; P < .01) and $1050 (95% CI, -$1878 to -$222; P = .02), respectively. These savings increased for colon cancer but disappeared for lung cancer in the second year. The program appeared to have no significant impact on any costs for participants with breast cancer in either of the years we examined.

Conclusions: Our results suggest that private payer-based SSP models can be associated with reduced costs for colon cancer care. There is weaker evidence of effects in lung cancer and no evidence in breast cancer. Such heterogeneous effects can inform future model development.