Comparing Hospital-Based Resource Utilization and Costs for Prostate Cancer Patients With and Without Bone Metastases

BACKGROUND Since 2010, several new treatments for prostate cancer (PCa), which have entered the US market, are poised to have an impact on treatment approaches; however, there is a paucity of evidence with respect to treatment patterns and costs. As new treatment patterns emerge, it will be imperative to understand treatment patterns and costs of care prior to the advent of novel treatments. OBJECTIVE As the PCa treatment landscape is evolving, this study sought to compare the hospital-based utilization and costs in two cohorts of patients with PCa: patients with bone metastases (w/BM) and patients without bone metastases (w/oBM). Comparisons were also made for patients with inpatient versus outpatient encounters. METHODS Patients in the Premier Perspective Database, a US hospital database, between January 2006 and December 2010, treated in an inpatient or outpatient setting for PCa (International Classification of Diseases, 9th Revision [ICD-9] diagnosis codes 185, 233.4) were included. Patients were required to be ≥40 years of age with no additional cancers. Patients were put into cohorts on the basis of the presence of bone metastases (ICD-9 code 198.5 or use of zoledronic acid or pamidronate disodium). Utilization of PCa-related treatments was compared, controlling for age, race, hospital type, payer type, bed size, and admission source and type. Differences in treatments were assessed utilizing logistic regression, while differences in costs were analyzed using gamma-distributed generalized linear models with a log-link function. All costs are reported in US$ 2010. RESULTS There were 23,747 hospitalizations for men w/BM (13,716 inpatient; 10,031 outpatient) and 187,708 hospitalizations (74,435 inpatient; 113,258 outpatient) for men w/oBM. The mean length of stay for men w/BM was 4 days compared with 2 days for men w/oBM (P < 0.0001). Overall, the mean cost per encounter was US$9,728 in men with w/BM and US$7,405 in men w/oBM (P = 0.0006). For inpatient stays, the mean cost per encounter was US$14,145 for men w/BM and US$11,944 for men w/oBM. For outpatient visits, the mean cost per encounter was US$3,688 for men w/BM and US$4,422 for men w/oBM. Men w/BM received hormone therapy (44.3%) and secondary hormone therapy (46.4%) most often, while men w/oBM received radiation (48.8%) and surgery (31.9%) most often. CONCLUSION Costs and utilization of PCa-related treatments vary on the basis of the presence of metastases and treatment setting (inpatient vs. outpatient).