The impact of insurance status on progression-free survival (PFS) and overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC)
Authors: Castro Daniela , Tripathi Nishita , Sayegh Nicolas , Gebrael Georges , Li Xiaochen , Meza Luis , Zengin Zeynep , Chehrazi-Raffle Alex , Govindarajan Ameish , Dizman Nazli , Ebrahimi Hedyeh , Chawla Neal , Mercier Benjamin , Hsu BS JoAnn , Shi Jessica , Philip Errol , Bergerot Cristiane , Barragan-Carrillo Regina , Pal Sumanta 
Published: August 2023

Abstract

Background
In addition to the previously studied socioeconomic factors associated with health disparities, insurance status can serve as a prognostic factor associated with overall survival in RCC patients (Zhang et al., Future Oncol 2019). Moreover, within this population, having access to health insurance has been reported to result in earlier detection of disease (Javier-DesLoges et al., JAMA Netw Open 2021). In this study, we explored the impact of primary and secondary insurance status on PFS and OS in patients receiving first line systemic therapy for mRCC.

Methods
Patients with mRCC from two NCI-designated comprehensive cancer centers diagnosed between 1990 and 2022 with available insurance information were retrospectively identified using institutional databases. Primary insurance information was categorized into three groups—Medicare, private insurance, and Medicaid/no insurance—while secondary insurance was defined by the presence or absence of secondary coverage. PFS and OS were estimated by Kaplan-Meier method and compared based on insurance status using log-rank tests. Univariate and multivariate Cox proportional hazard regression models were used to examine the impact of insurance status on PFS and OS.

Results
In total, 645 patients with mRCC had accessible information and were included in our analysis. Of these, 344 (53.3%), 250 (38.8%), and 51 (7.9%) had primary Medicare, private insurance, and Medicaid/no insurance, respectively. Overall, most patients were male (73.0%), with a median age of 60.0 (22.0-94.0) at time of diagnosis. The most commonly rendered first-line treatments were monotherapy with targeted agents (66.4%), dual immunotherapy (13.6%), and targeted/immunotherapy combinations (10.2%). Median PFS for the entire cohort was 6.6 months (95% CI, 5.9-7.7). Median PFS for patients with primary Medicare was 7.7 months (95%, CI 7.0-9.0), 5.5 months (95% CI, 4.0-7.0) for patients with private insurance, and 4.9 months (95% CI, 3.8-8.1) for Medicaid/uninsured patients. Using an overall log-rank test, a significant difference in PFS among the three groups with different primary insurance was observed (p&lt;0.0001). The median PFS for patients with secondary insurance was 8.1 months (95% CI, 6.6-11.3) compared to 6.1 months (95% CI, 5.5-7.4) for patients without secondary insurance. A multivariate Cox model with adjustment for other factors (such as age, gender, and ethnicity) revealed a statistically significant difference in PFS between patients with and without secondary insurance (p=0.0281). Median OS for the entire cohort was 36.8 months (95% CI, 32.4-44.3). Median OS for patients with primary Medicare, private insurance, and Medicaid/no insurance was 49.0 months (95%, CI 41.8-55.3), 28.5 months (95% CI, 24.1-35.7), and 21.6 months (95% CI, 17.5-42.3), respectively. By an overall log-rank test, a significant difference in OS across the three groups of primary insurance was observed (p=0.0003). No statistically significant differences in OS were observed between patients with and without secondary insurance. Overall, patients with primary Medicare had superior median PFS (p=0.0327) and OS (p=0.0004) compared to those with Medicaid/no insurance; although patients with private insurance had a lower risk of progression and death compared to those with Medicaid/no insurance, the result was not statistically significant.

Conclusions
In this real-world study, we investigated the impact of insurance status on clinical outcomes in patients with mRCC receiving systemic therapy. mRCC patients with primary Medicaid/no insurance or private insurance had inferior median PFS and OS compared to those with primary Medicare. Moreover, patients with secondary insurance had superior PFS over those with primary insurance alone. Overall, our findings suggest that insurance status may serve as a determinant of clinical outcomes. These hypothesis-generating data warrant external validation in prospective studies.