Early and long-term prognosis in patients with and without type 2 diabetes after carotid intervention: a Swedish nationwide propensity score matched cohort study

Objectives To investigate early and long-term outcomes after treatment of carotid artery stenosis in patients with type 2 diabetes (T2D) compared to patients without T2D. Design/method This observational nationwide population-based retrospective cohort study investigated all T2D patients treated for carotid stenosis registered in the National Swedish Vascular Surgery and the National Diabetes Registries. Data was collected prospectively for all patients after carotid intervention, during 2009-2015. We estimated crude early (within 30-days) hazard ratios (HRs) risk of stroke and death, and long-term HRs risk, adjusted for confounders with 95% confidence intervals (CIs), for stroke and death and major adverse cardiovascular events (MACE) by using inverse probability of treatment weighting matching. Results A total of 1341 patients with T2D and 4162 patients without T2D were included; 89% treated for symptomatic carotid stenosis, 96% with carotid endarterectomy. There was an increased early risk, HRs (95% CI), for stroke in T2D patients 1.65 (1.17-2.32), whereas risk for early death 1.00 (0.49-2.04) was similar in both groups. During a median follow-up of 4.3 (T2D) and 4.6 (without T2D), with a maximum of 8.0 years; after propensity score matching there was an increased HRs (95% CI) of stroke 1.27 (1.05-1.54) and death 1.27 (1.10-1.47) in T2D patients compared to patients without T2D. Corresponding numbers for MACE were 1.21 (1.08-1.35). Conclusions Patients with T2D run an increased risk for stroke, death, and MACE after carotid intervention. They also have an increased perioperative risk for stroke, but not for death.