National trends and comparative outcomes of insulin versus non-insulin therapy in acute ischemic stroke patients treated with mechanical thrombectomy: a retrospective cohort study using the national inpatient sample.

Background diabetes mellitus is prevalent among patients with acute ischemic stroke (AIS). The prognostic significance of long-term insulin treatment status, a marker of diabetes severity and duration, on outcomes after mechanical thrombectomy (MT) is not well characterized at the national level. Methods we performed a retrospective cohort study using the National Inpatient Sample (2006-2022) to identify adult AIS hospitalizations treated with MT and concomitant diabetes. Patients were categorized by documented long-term insulin use versus no such documentation, as a proxy for diabetes severity and disease burden. Primary outcomes were in-hospital mortality and non-home discharge. Secondary outcomes included peri-procedural complications. Propensity score matching was followed by machine learning to estimate adjusted risk differences (ARDs). Results we identified 7,859 matched discharges (3,931 insulin; 3,928 non-insulin). The proportion of MT patients with diabetes increased from 19.9% in 2006 to 31.5% in 2022; insulin use doubled from 11.6% to 20.4% of the diabetic subgroup. For the two pre-specified primary outcomes, insulin treatment status was associated with a higher adjusted risk of non-home discharge (ARD + 6.8% points; 95% CI, + 2.2 to + 11.4; P = 0.004), while in-hospital mortality did not differ between groups (13.6% vs. 14.5%; P = 0.254). In exploratory secondary analyses of peri-procedural complications, insulin-coded status was associated with lower rates of intracranial hemorrhage (- 4.8 points; 95% CI, - 9.1 to - 0.4), pulmonary complications (- 3.6 points; 95% CI, - 6.9 to - 0.3), and neurological complications (- 0.8 points; 95% CI, - 1.6 to 0.0), all with borderline statistical significance and without adjustment for multiplicity. Conclusions diabetes is increasingly prevalent among patients undergoing MT. Patients with documented long-term insulin use are more likely to require institutional discharge but experience lower complication rates. Insulin treatment status, likely reflecting diabetes severity and chronicity, may serve as a marker of functional prognosis and peri-procedural risk rather than a direct indicator of treatment effect. Future studies with pharmacologic data are warranted to individualize management strategies after thrombectomy. Clinical Trial Number: not applicable.