Trends and outcomes in Merkel cell carcinoma: A nationwide analysis of sociodemographic characteristics, inpatient utilization, and mortality (2016–2021).

e21592 Background: Merkel cell carcinoma(MCC) is an aggressive, rapidly progressing neuroendocrine malignancy of the skin. We aimed to analyse the burden of MCC in inpatient hospitalizations in the US. Methods: Patients admitted with MCC between 2016 and 2021 were identified from the Nationwide Inpatient Sample (NIS) using ICD-10 codes. The primary objective was to identify Sociodemographic characteristics using descriptive statistics. The secondary objectives were to determine the burden of inpatient hospital utilization, such as length of stay(LOS), Total hospitalization charges (THC), and mortality, using multivariate linear and logistic regression. Univariate linear regression models were used to examine the relationship of the outcomes across the years. Results: A total of 8,569 admissions were recorded, with 71% of the patients being male. The mean age of the population was 74.7 years. Among the cohort, 0.4% had a diagnosis of HIV, 5.3% had a history of solid organ transplantation (SOT), and 7.9% had a Concomitant hematological malignancy (CHM). Patients with HIV and SOT were significantly younger, with a mean age difference of 13.4 and 9.7 years, respectively (p < 0.005). The racial distribution showed that most patients were White (89.6%, OR of MCC 3.1, p < 0.001), belonging to zip codes with higher median incomes (28.6%). Medicare was the predominant payer, covering 79.8% of admissions. Hospital characteristics revealed that 93.5% of admissions took place in urban settings, with hospitals in the South having the highest number of admissions (37.3%), especially in the South Atlantic census division (21.7%). Regarding tumor location, the face was the most common site (24.4%), followed by the upper limb (18.6%) and scalp (16.3%). The odds hospitalization with MCC increased with age at 5.8% per year (OR 1.05, p < 0.001) and was higher among SOT (OR 4.7 p < 0.001) and CHM (OR 2.3, p < 0.001). No significant differences were observed among inpatient metrics based on age, gender, race, Median income, or the location of the MCC. Patients with HIV had shorter LOS (-6 days, p < 0.001), while patients with CHM had longer (+ 2 days, p < 0.05). The in-hospital mortality in patients with MCC was 6.8% , with the odds of mortality being higher with CHM (OR 2.8, p = 0.005). Though the odds of MCC hospitalizations increased from 2016 to 2021 by 7.5% per year(OR 1.07 p < 0.001), the trends in LOS, THC, and mortality did not reach statistical significance. Conclusions: The study shows that MCC hospitalizations have been increasing over the years and primarily involve elderly, White males in urban areas. Patients with SOT or CHM had worse outcomes, including more extended LOS and higher mortality. These findings highlight the need for targeted interventions for high-risk groups and further research to address disparities to improve care.