Background: Research on the relationship between sarcopenic obesity (SO) and multiple cardiovascular diseases is limited, and the regulatory roles of the Aggregate Index of Systemic Inflammation (AISI) and Systemic Inflammation Response Index (SIRI) remain underexplored. Methods: This retrospective observational study included participants aged >= 50 years who underwent routine health examinations between January 1 and December 31, 2024. SO was defined as a low skeletal muscle mass-to-weight ratio (< 33.9% in females, <39.3% in males) and high visceral fat area (>= 100 cm(2)). Participants were categorized into four groups: normal, sarcopenia, obesity, and SO. Adjusted multivariate analysis examined the association between SO and cardiovascular multimorbidities. The moderating effects of AISI and SIRI were analyzed using the Johnson-Neyman method and SPSS Process Macro. Results: This cross-sectional study included 1,010 participants aged >= 50 years. SO was significantly associated with endothelial dysfunction, arterial stiffness, degenerative heart valve disease, and carotid atherosclerosis, with odds ratios (95% confidence intervals) of 1.575 (1.017, 2.441), 1.382 (1.050, 1.818), 1.664 (1.033, 2.681), and 1.430 (1.022, 2.001), respectively. The Johnson-Neyman test identified AISI = 133.48 and SIRI = 0.58 as critical points for significant associations. Conclusion: SO is independently associated with increased cardiovascular disease risk. AISI and SIRI serve as biomarkers for risk stratification, highlighting the need for targeted management to improve cardiovascular outcomes in patients with SO.