Comparing Costs and Healthcare Resource Utilization Between nmHSPC and mHSPC Patients: A Retrospective Claims Analysis

Thesis (Master's)--University of Washington, 2021BACKGROUND: Prostate cancer has a high financial and health burden in the United States, being the most common cancer among American men. The disease typically manifests as localized non-metastatic hormone sensitive prostate cancer (nmHSPC) but can become metastatic and/or castration resistant. Metastatic hormone sensitive prostate cancer (mHSPC) is more difficult to treat than localized disease and requires different treatments than nmHSPC. Advanced disease can result in increased costs and healthcare resource utilization (HCRU), placing additional burden on patients, payers, and the health care system. Although studies have been conducted on the differences in costs and HCRU between non-metastatic castration-resistant prostate cancer and metastatic castration-resistant prostate cancer patients, no studies have been conducted yet in the HSPC setting. OBJECTIVE: Our objective was to estimate the differences in HCRU and costs for nmHSPC and mHSPC patients and their payers. METHODS: We conducted a retrospective cohort analysis using claims data from the IBM® MarketScan® Commercial and Medicare Supplemental databases. Our patient population consisted of male adult patients HSPC, split into non-metastatic and metastatic cohorts. HSPC was defined as having at least one inpatient services claim or two outpatient services claims within six months with a prostate cancer diagnosis. Additionally, patients must have had a claim evident of androgen deprivation therapy use within six months of their initial observed diagnosis date. Metastatic patients must have had a secondary diagnosis code of metastasis with their initial claim with prostate cancer as a primary diagnosis. The index date and follow-up period began 12 months after the initial diagnostic date, with 12 months of follow-up. Patients must have been continuously enrolled from their first diagnostic claim until the end of their follow-up period 24 months later. The 12-month follow-up period was used to assess the outcomes of interest, which were the difference between nmHSPC and mHSPC cohorts in terms of mean annual patient out of pocket (OOP) and payer costs, and healthcare resource utilization in terms of mean annual days spent hospitalized, outpatient prescription fills, and unique visits to outpatient services. Linear regression models were used to assess the outcomes during the follow-up period, adjusting for age, geographical region, plan type, and Charlson Comorbidity Index (CCI) score category. RESULTS: A total of 4,239 patients met the study inclusion and continuous enrollment criteria. On average, the 12-month costs of mHSPC patients were significantly greater than that of nmHSPC patients for both patient OOP ($1,336; 95% CI: $1,064 to $1,608) and payer ($65,368; 95% CI: $57,248 to $73,488) costs. mHSPC patients also had higher mean annual outpatient prescription fills (8.38 fills; 95% CI: 6.03 to 10.72) and unique outpatient services visits (9.81 visits; 95% CI: 7.60 to 12.02). There was no statistically significant difference observed for mean annual days spent in inpatient services between the two cohorts. Subgroup analysis for age indicated that mHSPC patients had greater costs and HCRU than nmHSPC patients, although the under 65 years subgroup observed a significantly greater difference than the 65 years and older subgroup. Geographic region subgroup analysis shows that the mHSPC patients in the South had the greatest incremental cost difference compared to other regions. CONCLUSIONS: Our analysis suggests that compared to nmHSPC patients, individuals with mHSPC impose a significantly greater financial burden on themselves and payers as well as incur greater healthcare resource utilization. There did not appear to be statistically significant differences in terms of hospitalization costs and inpatient resource utilization. Younger patients, under the age of 65, appear to have higher incremental costs and HCRU compared to those 65 years and older, which may be driven by more aggressive treatment