BackgroundSerum uric acid (SUA), an end-product of purine catabolism diffused in the blood, is positively associated with the risk of type 2 diabetes mellitus (T2DM). However, in the T2DM population, the association of SUA fluctuation (DeltaSUA) with the functional outcome of ischemic stroke (IS) is still unclear. Accordingly, this study aimed to assess the correlation between DeltaSUA and short-term IS functional outcomes in T2DM patients.MethodsAll T2DM patients diagnosed with IS in the China National Stroke Registry III were included. DeltaSUA, which was defined as the difference between the SUA levels at baseline and 3 months after symptom onset, was classified into two groups, i.e., elevated DeltaSUA (DeltaSUA > 0) and reduced DeltaSUA (DeltaSUA le 0). The outcomes measured using the Modified Rankin Scale (mRS) were scored from 0 to 6, and poor functional outcome was defined as an mRS score of 3–6 at 3 months after IS.ResultsAmong the 1255 participants (mean age: 61.6 ± 9.8 years), 64.9% were men. Patients with elevated DeltaSUA had a lower incidence of poor functional outcomes at 3 months. Compared with reduced DeltaSUA, elevated DeltaSUA at 0–50 μmol/L (odds ratio [OR] = 0.46, 95% confidence interval [CI] = 0.28–0.78, p = 0.004) and 50–100 μmol/L (OR = 0.40, 95% CI = 0.21–0.77, p = 0.006) was significantly correlated with a reduced risk of poor functional outcomes at 3 months.ConclusionThis study showed that a moderate increase in DeltaSUA in the range of 0–100 μmol/L at 3 months after IS might be beneficial in T2DM adults and more studies are warranted to confirm this.