Background: Corticosteroids are used in the management of castration-resistant prostate cancer (CRPC) to reduce tumor-related symptoms because of CRPC therapies. Since corticosteroids have been associated with a range of toxicities, their use may increase the economic burden sustained by patients with CRPC. However, the economic impact of using corticosteroids in patients with CRPC has not been well characterized.
Objective: To assess the effect of previous corticosteroid use on health care resource utilization (HRU) and health care costs among men with CRPC.
Methods: Using administrative claims data (2007-2016), adult chemotherapy-naive patients who initiated CRPC treatment following surgical or medical castration were identified. Based on the cumulative corticosteroid dose during the 12 months before CRPC treatment initiation, patients were grouped into 4 cohorts: no corticosteroid (0 gm), low corticosteroid (< 0.5 gm), medium corticosteroid (0.5-2.0 gm), and high corticosteroid (> 2.0 gm). All-cause HRU and costs (2017 U.S. dollars) were compared between cohorts during the 1-year study period following CRPC treatment initiation using the no corticosteroid cohort as reference. Multivariable regression models were used to adjust for baseline covariates, including age, region, index year, Charlson Comorbidity Index score, presence of bone metastases, baseline all-cause HRU, and corticosteroid-related clinical events during baseline.
Results: 9,425 patients were included (no corticosteroid = 6,765, low corticosteroid = 1,660, medium corticosteroid = 655, and high corticosteroid = 345). On average, patients in the no corticosteroid cohort were older and had a lower baseline HRU and comorbidity burden than patients in the other 3 cohorts. During the study period, patients with corticosteroid exposure (across all corticosteroid cohorts) had significantly more inpatient admissions (high corticosteroid vs. no corticosteroid adjusted incidence rate ratio [IRR] = 1.56; P < 0.001), emergency department visits (high corticosteroid vs. no corticosteroid adjusted IRR = 1.30; P = 0.001), and outpatient visits (high corticosteroid vs. no corticosteroid adjusted IRR = 1.11; P < 0.001). In addition, compared with the no corticosteroid cohort, patients with corticosteroid exposure had significantly higher monthly total costs (high corticosteroid vs. no corticosteroid adjusted difference = $2,600; P < 0.001), including medical service costs (high corticosteroid vs. no corticosteroid adjusted difference = $1,564; P < 0.001) and pharmacy costs (high corticosteroid vs. no corticosteroid adjusted difference = $825; P < 0.001).
Conclusions: Cumulative corticosteroid exposure before CRPC treatment initiation was associated with significantly higher HRU and costs. This increase in economic burden was more prominent among patients with annual cumulative corticosteroid doses of more than 2.0 gm. These results suggest that previous corticosteroid use may result in a higher economic burden among patients with CRPC.
Disclosures: This study was funded by Astellas Pharma (Northbrook, IL) and Medivation, a Pfizer Company (San Francisco, CA), the codevelopers of enzalutamide. The study sponsor was involved in the study design, data interpretation, and review. All authors contributed to the development of the manuscript and maintained control over the final content. Schultz and Wilson are employed by Astellas Pharma. Schultz owns stock in Gilead Sciences and Shire. Song and Yang are employed by Analysis Group, which received consultancy fees from Astellas Pharma. Ramaswamy is employed by Pfizer, and Lowentritt is employed by Chesapeake Urology and has served as a speaker and consultant for Astellas Pharma, Pfizer, Bayer, Dendreon, and Janssen. A synopsis of the current research was presented in poster format at the AMCP Managed Care & Specialty Pharmacy Annual Meeting 2019, which took place in San Diego, CA, on March 25-28, 2019.