600 Surgical site infection risk by migration status in a tertiary hospital in Barcelona, Spain

OP 20: Challenges and Opportunities for Health 1, B308 (FCSH), September 4, 2025, 13:30 - 14:30 Aims Evidence shows that social determinants of health drive healthcare-associated infection inequalities, but evidence is lacking in the European context. To address this gap, we aimed to compare surgical site infection (SSI) rates by migration status (MS) in a tertiary hospital in Barcelona using prospective surveillance data. Methods We conducted a retrospective cohort study of patients who underwent surgery at Clínic Barcelona hospital (2008-2024). Follow-up time was 30–90 days. MS was defined as having citizenship from, or being born in, a country other than Spain. The primary outcome was the incidence rate of SSIs. We obtained incidence rate ratios (IRRs) and their corresponding confidence intervals (CI) using modified Poisson regression models, to compare SSI risk between migrant and native patients. We report preliminary results based on complete case analysis. Results A total of 5,799 surgical interventions were included, of which 490 (8.4%) were performed in migrant patients: 2496 (43%) orthopedic arthroplasties, 2,069 (35.7%) colon/rectal resections, and 1234 (21.3%) cardiac surgeries. A total of 531 SSIs occurred during follow up. Overall (IRR 0.64, 95% CI: 0.44–0.93, p = 0.02) and in males (IRR 0.56, 95% CI: 0.33 0.95, p = 0.03), migrants had a lower risk of SSI. Considering SSI depth, migrants had a lower risk of superficial infections (IRR 0.41, 95% CI: 0.21-0.80, p = 0.009), but migrant females had a higher risk of deep infections (IRR 3.70 95% CI: 1.61-8.54, p = 0.002). Among procedure subgroups, no statistically significant differences were observed, except for cardiac surgeries (IRR 0.46, 95% CI: 0.24–0.88, p = 0.02). Conclusions Inequalities exist in the SSI risk between natives and migrants with full access to the Spanish National Health System: while migrants’ overall risk is lower, probably due to the “Healthy Immigrant Effect”, female migrants might face a higher risk of deep infections.