Effect of Metformin in Diabetic Patients After Treatment of Intracranial Aneurysm: A Nationwide Cohort Study

Abstract

Background: Intracranial aneurysm (IA) is the most common cause of subarachnoid hemorrhage (SAH), causing high morbidity and mortality. Experimental data have shown that metformin, an antidiabetic agent, has protective effects against IA rupture. This study assessed the effect ofmetformin on the long-term prognosis of diabetic patients treated for IA. Methods: This retrospective cohort study included diabetic patients who underwent surgical clipping or endovascular coiling for IA between January 2009 and December 2020, based on Korean health insurance claims data. The primary outcome was the development of SAH. The risk associated with metformin use was evaluated using a multivariable Cox proportional hazards model supplemented with subgroup, propensity score matching, and time-varying Cox regression analyses. Results: Of 14,086 diabetic patients treated for IA, 9,612 (68.2%) were metformin users. During a mean follow-up of 4.6 years, 120 (0.9%) patients experienced SAH. Metformin use was associated with a reduced risk of SAH (adjusted hazards ratio, 0.63; 95% confidence interval, 0.41-0.95; P = 0.028). This finding was consistent in subgroup, propensity score matching, and time-varying Cox regression analyses. Conclusion: Metformin use in diabetic patients treated with clipping or coiling for IA was associated with reduced risk of SAH. These findings support the use of metformin as the preferred antidiabetic agent for such patients considering these benefits.