目的·基于2021年全球疾病负担（Global Burden of Disease，GBD）研究（GBD 2021）项目，构建心血管-肾脏-代谢（cardiovascular-kidney-metabolic，CKM）指数，系统评估心血管疾病、慢性肾脏病与代谢性疾病的协同负担特征，揭示其在全球范围内的时空分布规律和相互关联性。方法·数据来源于GBD 2021项目，涵盖1990—2021年204个国家和地区。提取缺血性心脏病、慢性肾脏病与2型糖尿病的伤残调整生命年（disability-adjusted life year，DALY）率，计算年龄标准化DALY率，并采用Z分数标准化后等权重算术平均值作为CKM指数。利用Joinpoint回归模型对CKM指数的时间序列进行趋势分段拟合，识别不同发展阶段的变化拐点及年均变化率。结合社会人口学发展指数（socio-demographic index，SDI）分区，对不同国家和地区进行归类比较。使用Spearman秩相关分析检验3类疾病DALY率之间的相关性。结果·2021年，全球CKM指数为0.201。时间趋势分析显示1990—2021年全球CKM综合征负担总体呈上升趋势，年均增幅为0.002 9。其中，中SDI国家的增长最为显著，CKM指数由-0.130上升至0.783，年均增幅为0.029 4；中高SDI国家与中低SDI国家亦呈现稳定上升趋势，年均增幅分别为0.009 7和0.009 2；而在高SDI国家中，CKM指数自1990年的0.847下降至2010年的0.783，随后略回升至2021年的0.792。全球204个国家和地区的相关性分析显示3类疾病DALY率之间存在不同程度的正相关，其中慢性肾脏病与2型糖尿病相关性最强（r=0.66，P<0.001），缺血性心脏病与慢性肾脏病相关性较弱（r=0.20，P=0.004）。结论·研究构建的CKM指数可为评估多疾病共存负担提供分类量化工具。CKM指数分析结果揭示了心血管疾病、慢性肾脏病与代谢性疾病既存在共同危险因素，也存在协同进展的病理通路，应成为全球慢性疾病防控的重点线索。建议公共卫生政策打破体系分隔，强化对CKM综合征的快速识别与全程管理，提升慢性疾病防治效率。

Objective ·To construct a cardiovascular-kidney-metabolic (CKM) index based on the Global Burden of Disease (GBD) 2021 study, systematically evaluate the synergistic burden of cardiovascular diseases, chronic kidney diseases, and metabolic disorders, and reveal their spatiotemporal distribution patterns and interrelationships worldwide. Methods ·The data were derived from the GBD 2021 project, encompassing 204 countries and regions over the period from 1990 to 2021. The disability-adjusted life year (DALY) rates for ischemic heart disease, chronic kidney disease, and type 2 diabetes mellitus were extracted, age-standardized DALY rates were calculated, and then the CKM index was computed through equal-weighted averaging of these rates after Z-score standardization. The Joinpoint regression models were applied to the CKM index time series for segmented trend fitting, to identify turning points and annual percentage changes at different developmental stages. Countries and regions were categorized and compared according to their socio-demographic index (SDI) levels. Spearman's rank correlation was used to assess the correlations among DALY rates for the three disease categories. Results ·In 2021, the global CKM index value was 0.201. Temporal trend analysis showed that global CKM syndrome burden generally increased from 1990 to 2021, with an average annual increase of 0.002 9. Among these, middle-SDI countries showed the most significant growth, with CKM index rising from -0.130 to 0.783, representing an average annual increase of 0.029 4. High-middle SDI and low-middle SDI countries also demonstrated steady upward trends, with average annual increases of 0.009 7 and 0.009 2, respectively. In high-SDI countries, the CKM index declined from 0.847 in 1990 to its lowest point of 0.783 in 2010, and then rose slightly to 0.792 in 2021. Correlation analysis across 204 countries and regions globally revealed varying degrees of positive correlation among the three types of diseases in terms of DALY rates, with the strongest correlation observed between chronic kidney disease and type 2 diabetes mellitus (r=0.66, P<0.001), while the correlation between ischemic heart disease and chronic kidney disease was weaker (r=0.20, P=0.004). Conclusion ·The CKM index developed in this study provides a categorized and quantitative tool for assessing the burden of multimorbidity. The application of CKM index analysis revealed that cardiovascular diseases, chronic kidney diseases, and metabolic diseases not only share common risk factors but also have synergistic pathological pathways, which should be key clues for global chronic disease prevention and control. Public health policies should break down system silos, strengthen rapid identification and comprehensive management of CKM, and improve the efficiency of chronic disease prevention and treatment.