MP26-18: Underinsurance is associated with increased risk of multiple procedures for kidney stones

Cameron Hicks*, David Bayne, San Francisco, CA, sudarshan Srirangapatanam, Orlando, FL, Manuel Armas-Phan, Atlanta, GA, Efstathios Gennatas, Johsias Maru, San Francisco, CA

Introduction: Urolithiasis affects approximately 9% of the United States population. Recent literature suggests that underinsurance is associated with larger, more complex stones. However, this relationship has only been demonstrated at the institutional level. Given high costs and recurrence rates, and that patients from lower socioeconomic status (SES) communities have less access to care, we aimed to determine if under-insurance is associated with multiple surgeries within one year using a statewide dataset.

Methods: A review of prospectively collected data using the California Office of Statewide Health Planning and Development (OSHPD) was conducted. This study included adult patients who had their first recorded kidney stone encounter between 2009-2019 and underwent at least one urologic stone procedure. Any patients with a documented history of urothelial carcinoma were excluded. All univariate tests were performed with a Chi-squared test for categorical variables and Student’s t-test for continuous variables. All data analyses were conducted using R version 4.0. This study was approved by the UCSF Institutional Review Board (IRB).

Results: A total of 168,197 patients were included in the study population. Patients with private insurance had significantly higher rates of SWL (24.8%) and lower rates of PNL (8.0%) compared to the other insurance types. The rates of surgical recurrence overall were highest in PNL, and within the PNL cohort recurrence was highest among Medicaid patients. PNL was also associated with higher odds of multiple surgeries (OR 1.12, 95% CI [1.08-1.17] p < 0.001). Compared to Private insurance, Medicaid (1.44 [1.39-1.50] p < 0.001) and Medicare (1.10 [1.06-1.14] p < 0.001) insurances were associated with significantly greater odds of second surgery. Lastly, non-Hispanic Black patients (1.15 [1.08-1.22] p < 0.001) were found to have statistically significant differences in odds of surgical recurrence compared to Non-Hispanic White patients.

Conclusions: In a statewide, California database underinsured patients, Black patients, patients who received PNL, and patients with more comorbidities were at higher risk of undergoing a second procedure for kidney stones within one year of initial surgical treatment. This study adds to the expanding body of literature linking suboptimal healthcare access and disparate outcomes for kidney stone patients. More research is needed to further investigate the relationship between healthcare access and kidney stone disease.

Source of Funding: 1K12DK111028