Commercial vs. Medicaid insurance and use of high-priced anticancer treatments.

Abstract

6599 Background: Financial incentives presented by the larger markups on cancer drugs among commercial payors may result in increased use of high-priced drugs among commercially insured vs. Medicaid insured patients. We evaluated the association between patient insurance type and the likelihood of receiving higher-priced treatments. Methods: We linked cancer registry, administrative claims, and demographic data for individuals diagnosed with cancer in North Carolina from 2004-2011, who had either commercial or Medicaid insurance. We selected cancer types with multiple FDA-approved, guideline-recommended chemotherapy options, and large differences in price between the higher-priced and lower-priced options during the study period: advanced colorectal, lung, and head-and-neck cancer (HNC). The primary outcome was receipt of the higher-priced treatment option, and the primary exposure was insurance type: commercial vs. Medicaid. We estimated risk ratios (RR) for the association between insurance type and higher-priced treatment using log binomial models with inverse probability of exposure weights to control confounding by age, county-level poverty prevalence, and selected comorbidities. We assessed for potential modification of the RR by setting (hospital outpatient vs. physician office) and academic designation (NCI-designated comprehensive cancer center vs. other); these were exploratory analyses due to sparse data and subsequently limited confounding control. Results: Of 812 patients: 209 (26%) had Medicaid insurance; 311 (38%) had NHC, 263 (32%) colon or rectal cancer, and 238 (29%) lung cancer. The crude risk of higher-priced treatment was 36% (215/603) for commercially insured and 27% (57/209) for Medicaid insured (RR:1.31, 95%CI 1.02-1.67). After weighting the association was attenuated (RR:1.15, 95%CI 0.81-1.65). While limited by imprecision and the potential for uncontrolled confounding, exploratory subgroup analysis suggested that, compared to Medicaid insurance, commercial insurance was associated with numerically higher risk of higher-priced treatment among patients treated by non-NCI designated providers (RR:1.53, 95%CI 1.14-2.04), and within both the physician office (RR:1.36, 95%CI 0.95-1.95) and hospital outpatient (RR:1.08, 95%CI 0.58-2.02) settings, but lower risk of high-priced treatment within NCI cancer centers (RR:0.39, 95%CI 0.22-0.71). Conclusions: Individuals with Medicaid vs. commercial insurance access high-priced treatments at a similar proportion after accounting for differences in case mix, morbidity, and SES. However, modification of the association by and academic setting, observed in exploratory subgroup analysis, suggests the possibility that insurance type may affect treatment for some patient groups. This study was limited by focus on a single state and the potential for residual confounding.