Objective To understand the incidence of cerebral infarction in Shandong province during 2020-2021, and provide reference for the prevention and treatment of cerebral infarction.

Methods The incidence data of cerebral infarction in Shandong during 2020−2021 were obtained from the Chronic Disease Surveillance Information Management System of Shandong province for a descriptive analysis. Excel 2013 and SAS 9.4 were used for data process and calculation of incidence rate and standardized incidence rate of cerebral infarction. ArcGIS10.8 software was used to analyze the global and local spatial autocorrelation. Circular distribution analysis was performed using Excel 2013 to describe the seasonal distribution of cerebral infarction incidence during 2020−2021.

Results The average annual crude incidence rate and the standardized incidence rate of cerebral infarction were 483.24/100 000 and 323.84/100 000, respectively, in Shandong during 2020−2021, and the incidence rate of cerebral infarction was higher in men (557.45/100 000) than in women (413.77/100 000) and higher in rural area (561.54/100 000) than in urban area (391.37/100 000). The median age of onset in 2020 and 2021 were 68.98 years and 69.10 years, respectively. The incidence of cerebral infarction in people aged ＜40 years was low, and the incidence increased rapidly after 50 years old. The onset time showed some clustering indicated by circular distribution based on monthly observation (P＜0.001, r=0.07). The M (P₂₅, P₇₅) of the crude incidence rates of cerebral infarction in 2020 and in 2021 were 458.70/100 000 (363.30/100 000, 585.80/100 000), 505.41/100 000 (383.79/100 000, 655.87/100 000), the M (P₂₅, P₇₅) of the standardized incidence rate was 310.73/100 000 (226.79/100 000, 396.09/100 000), 341.64/100 000 (241.98/100 000, 453.12/100 000), showing a west-high east-low distribution. Global spatial autocorrelation analysis showed that the overall distributions of the crude incidence rates of cerebral infarction (Moran's I=0.47, 0.56) and the standardized incidence rates (Moran's I=0.55, 0.61) showed spatial positive correlation (P<0.001), with certain spatial clustering. Local spatial autocorrelation analysis showed that the high - high cluster of cerebral infarction incidence was mainly distributed in Binzhou, Dezhou and Liaocheng in northwestern Shandong, and Ji'nan, Tai'an and Jining in central and southern Shandong.

Conclusion The incidence of cerebral infarction in Shandong is serious, with certain spatial clustering, and the elderly and men are the high-risk groups. The incidence is high in spring and in western Shandong. So it is necessary to take appropriate preventive and treatment measures to mitigate the burden of cerebral infarction.