BACKGROUND: A comprehensive epidemiological investigation of the coexistence between diabetes and stroke/TIA in China is urged. METHODS: Data from the Chinese Stroke Center Alliance program, a nationwide multi-center registry study, were used to detect the prevalence, awareness, treatment, and control of diabetes among stroke/TIA. The distribution of diagnosed and undiagnosed diabetes and prediabetes among stroke/TIA patients was investigated, the medical care around diabetes and their respective risk predictors were analyzed, and the association of all above diabetes characteristics with in-hospital death was evaluated using multi-variable Cox regression models. RESULTS: Of 980 625 patients included, 308 426 (31.5%) had prediabetes, while 365 052 (37.2%) had diabetes, with nearly a third of them undiagnosed (112 969, 30.9%). Of residual aware diabetic patients, 59.0% were treated, with 27.3% controlled. Compared to Han ethnicity, Zhuang ethnicity had a lower prevalence of diabetes (37.3% vs. 35.1%) but were less aware (69.4% vs. 56.5%), treated (59.4% vs. 47.8%), and controlled (27.4% vs. 26.0%). Patients with prediabetes, diagnosed, and undiagnosed diabetes had increasingly higher risks of in-hospital death (adjusted HR [95% CI]: 1.47 [1.35-1.60]
2.15 [1.97-2.34]
4.20 [3.87-4.56], all p <
0.002). Unaware and untreated diabetes were independently associated with in-hospital death (adjusted HR [95% CI]: 1.99 [1.85-2.14]
2.84 [2.63-3.07, both p <
0.002]). Compared with controlled diabetes, those with uncontrolled diabetes had a lower risk of in-hospital death (adjusted HR [95% CI]: 0.77[0.68-0.88], p <
0.002). CONCLUSIONS: The findings indicate that over two-thirds of stroke/TIA patients are exposed to diabetes in China, causing higher in-hospital mortality, which should be screened and intervened early.