Aims <p>This study aimed to investigate the association between the weight-adjusted waist circumference index (WWI) and cardiovascular outcomes in patients with T2DM.</p> Methods <p>Using Cox proportional hazards regression models to determine the impact of WWI on cardiovascular event. Nonlinear associations were explored through restricted cubic splines (RCS) and smooth curve fitting (SCF), and the integrity of these findings was supported by subgroup and sensitivity analyses.</p> Results <p>An elevation in WWI was linked to a significant rise in the likelihood of major adverse cardiovascular events (MACEs), composite cardiovascular outcomes MSD, including myocardial infarction, stroke, and any death, congestive heart failure (CHF), and total mortality (TM). An increase of per 1 standard deviations (SD) in WWI corresponded to a 7% heightened risk of MACEs (HR: 1.07, 95% CI: 1.02, 1.13), a 9% greater risk of MSD (HR: 1.09, 95% CI: 1.04, 1.13), a 20% greater risk of CHF (HR: 1.20, 95% CI: 1.10, 1.30), and a 11% increase in TM (HR: 1.11, 95% CI: 1.06, 1.17). RCS and SCF analysis revealed a nonlinear correlation between WWI and the risks of CHF and TM. Subgroup analyses demonstrated that WWI more accurately predicted CHF risk in patients whose duration of diabetes was under 10 years. Sensitivity analyses reinforced the reliability of these results.The integration of WWI into conventional predictive models improved the accuracy of these outcomes.</p> Conclusions <p>WWI is closely associated with future cardiovascular outcomes and TM in patients with T2DM.WWI serves as an autonomous predictor of both future cardiovascular events and TM among patients with T2DM, outperforming traditional obesity indices in predictive ability.</p> Clinical trial URLs <p><a href="https://clinicaltrials.gov/ct2/show/NCT00000620">https://clinicaltrials.gov/ct2/show/NCT00000620</a></p>