Introduction: A frequent complication of stoma creation is parastomal herniation (PSH), defined as any palpable bulge or radiologic defect containing bowel in the parastomal region. Reported incidence rates are up to 50% for patients in the 24 months following ileal conduit (IC) surgery. To better understand risk factors for PSH in those undergoing cystectomy and ileal conduit (RC/IC) procedure, we examined a contemporary cohort of patients through combined Surveillance, Epidemiology and End Results-Medicare data (SEER-MD). Methods: Using SEER-MD, patients with PSH after cystectomy and IC were identified. This was performed using CPT codes to identify surgery patients and subsequent diagnostic the new ICD-10 PSH specific code (K43.5) post-surgery, for those with surgery between 2015 and 2019. Risk factors of interest included: race, sex, socioeconomic status, marital status, COPD, smoking, obesity status, neoadjuvant chemotherapy administration, and tumor stage. An adjusted Cox Proportional-Hazards model was utilized for statistical analysis, enabling assessment of time to PSH from receipt of surgery and to account for censored patients. Results: Of 1,838 patients identified as having undergone RC/IC, 132 patients (7 %) developed PSH in the followup period. The median time to PSH was 11.5 months (IQR: 6.5-18.7 months). The greatest risk factor in our cohort of patients for development of PSH was obesity (HR 2.05, 95% CI 1.48-2.98). The lowest socioeconomic quartile was also associated with greater risk of PSH (HR 1.49, 95% CI 1.01-2.22). Sex, COPD diagnosis, gender, race, smoking status, neoadjuvant chemotherapy, and tumor stage were not significantly associated with risk of PSH, although the female sex, Black/Hispanic race, and pT4 lesions showed elevated HR estimates. Marital status of “Divorced/Separated/Widowed” was significantly associated with PSH (HR 1.66, 95% CI 1.04-2.66) vs. “Married”, however due to a large portion of “unknown” marital status in our cohort, this finding may not be clinically meaningful. Conclusions: While the SEER-MD incidence rate is far below 50%, this reflects a mutable coding process subject to variation in capture by provider. With the available cohort, our model demonstrated an increased risk of PSH for obese and low SES patients undergoing RC/IC surgery. Both weight loss prevention strategies and careful symptom monitoring must be pursued in this population. SOURCE OF Funding: None
