Abstract TP362: Accelerated Intracranial Aneurysm Growth in Type 2 Diabetic Patients

Background: Although type 2 diabetes mellitus (T2DM) has been reported as a protective factor against aneurysmal subarachnoid hemorrhage, emerging evidence suggests that accelerated vascular aging in diabetic patients may promote more rapid growth and instability of unruptured intracranial aneurysms. We performed a meta-analysis to reevaluate the overall risk profile of intracranial aneurysm growth in patients with T2DM. Methods: A systematic literature search was performed for cohort and case-control studies reporting on intracranial aneurysm growth in diabetic versus non-diabetic adults. Available literature up to July 2025 was included. Pooled relative risks (RR) and 95% confidence intervals (CI) were calculated using a random effects model. Prediction intervals were generated to assess the expected range of effects in future studies. Leave-one-out sensitivity analyses were conducted to evaluate the influence of individual studies. Publication bias was assessed by funnel plot symmetry, Egger's regression test, and trim-and-fill adjustment. Results: Eighteen studies comprising 3,157 patients (372 with T2DM, 2,785 non-diabetics) met inclusion criteria. Diabetic patients exhibited a 33% higher risk of aneurysm growth compared to non-diabetics (RR 1.33; 95% CI 1.03–1.72). The 95% prediction interval (1.01–1.76) indicates that future studies are likely to observe a similar increased risk. In leave-one-out analyses, the pooled RR ranged from 1.27 to 1.37, with all point estimates remaining >1.0 and no increase in heterogeneity (I 2 =0%). Funnel-plot inspection showed symmetry, and Egger’s test was non-significant (t = –1.52, p = 0.15). Trim and fill imputed four studies in non-significant zones (p>0.1), yet the adjusted RR remained robust (1.44; 95% CI 1.13–1.83). Meta-regression showed no significant effects of female proportion, patient or aneurysm growth proportion, mean age, follow-up duration, or growth definition (all p>0.05). Similarly, subgroup analyses revealed no significant differences by country (p = 0.70), imaging modality (p=0.81), study design (p=0.70), or growth threshold (p = 0.85). Conclusions: Although T2DM may reduce aneurysm rupture, our results show a clear and consistent increase in aneurysm growth among diabetic patients. These findings support closer imaging follow-up and earlier intervention when appropriate.