BACKGROUND: The growing proportion of older individuals worldwide is anticipated to lead to an increase in the number of elderly patients requiring surgery for colon cancer. Consequently, it is crucial to identify specific risk factors for mortality and complications after colon surgery in this age group. METHODS: The Swedish part of the ERAS registry (EIAS) between 2009 and 2022 was used. Patients aged ≥ 75 years undergoing colon surgery were compared with younger patients regarding risk factors for severe complications and mortality after multivariate regression analysis. RESULTS: After adjusting for potential confounders, three risk factors specifically associated with severe complications in elderly patients were identified: severe pulmonary disease (OR 1.64
95% CI 1.04-2.58), recent immunosuppressive treatment (OR 1.92
95% CI 1.12-3.30), and left hemicolectomy (OR 1.43
95% CI 1.04-1.97). Furthermore, four risk factors for mortality, statistically significant only in the older age group, were found: male sex (OR 1.73
95% CI 1.08-2.76), ASA ≥ 3 (OR 2.92
95% CI 1.66-5.15), severe pulmonary disease (OR 2.28
95% CI 1.02-5.06), and open surgery (OR 1.68
95% CI 1.04-2.73). CONCLUSION: Several risk factors for severe complications and 30-day mortality specific to the elderly group were identified. Among these, severe pulmonary disease was associated with both severe complications and mortality.