Assessment of health care resource utilization (HRU) in patients with castration-resistant prostate cancer (CRPC).
89 Background: Although patients with CRPC frequently develop metastasis within 3 years following castration resistance, the impact of metastasis on HRU in these patients is not well understood. Methods: The Optum de-identified electronic health record database (1/1/2007 – 4/30/2016) was used in this single cohort observational study comparing HRU after metastasis with HRU before metastasis. The cohort included only non-metastatic CRPC (nmCRPC) patients who later developed metastasis. The pre-metastasis period spanned from nmCRPC identification to development of metastasis; the post-metastasis period spanned from metastasis until death or end of data availability. Per-patient per-month (PPPM) HRU was estimated during both pre- and post-metastasis periods by a generalized linear mixed model adjusted for log-transformed baseline PSA, age, testosterone levels, and Charlson Comorbidity Index. Results: With a mean time of 11 and 17 months of pre- and post-metastasis periods, respectively, 540 CRPC men were included, with a mean age at nmCRPC identification of 75 years. Higher HRU was seen across all service types during the post-metastasis period. There was a 2.5-fold increase in inpatient admissions and a 6.4-fold increase in inpatient length-of-stay in the post-metastasis period compared to the pre-metastasis period (p < 0.01). For emergency department (ED) visits, there was a 2.0-fold increase from the pre- to post-metastasis periods (p < 0.01). For observation unit visits, a 2.7-fold increase was seen in the post-metastasis period (p < 0.01). Finally, patients were 40% more likely to have an office visit after developing metastasis (p < 0.01). The PPPM use of intensive care unit, hospice or skilled nursing facility were too low for meaningful comparison between the pre- and post-metastasis periods. Conclusions: Shorter time to metastasis was observed in this cohort vs. other nmCRPC studies, likely due to delayed disease identification. CRPC patients incurred substantially higher HRU after developing metastasis, attributable to inpatient, ED, observation unit as well as office visits, suggesting that delaying metastasis may reduce or delay the increased HRU in patients with nmCRPC.