This study aims to address the following key scientific question by establishing a large-scale, high-standard clinical cohort: the independent contribution of MASLD and its progression to liver fibrosis on cardiovascular outcomes in patients with T2DM, after excluding the confounding effects of traditional cardiovascular risk factors. Its technical value lies in utilizing prospective follow-up data combined with a multivariable competing risks model to develop and validate a cardiovascular risk prediction and early warning system tailored for Chinese populations with T2DM complicated by MASLD. Clinically, the findings will provide interdisciplinary evidence-based support for endocrinology and cardiology, helping clinicians identify high-risk individuals and prevent cardiovascular events through early intervention targeting hepatic metabolic disorders. This has significant implications for reducing overall mortality among diabetic patients in China and alleviating the public health burden.

Inclusion Criteria:

• 1.Age ≥18 years, male or female;

  2.Meet the diagnostic criteria for type 2 diabetes mellitus (T2DM) according to the Chinese Guideline for the Prevention and Treatment of Type 2 Diabetes (2022 edition), with a confirmed diagnosis for at least 3 months;

  3.Meet the diagnostic criteria for metabolic dysfunction-associated steatotic liver disease (MASLD) according to the *Chinese Guideline for the Diagnosis and Treatment of Metabolic Dysfunction-Associated Steatotic Liver Disease (2024 edition)*, with preliminary assessment including liver enzymes (ALT/AST), liver ultrasound, and non-invasive fibrosis markers (FIB-4, LSM), and exclusion of other liver diseases;

  4.Willing to participate in this study and provide written informed consent;

  5.Able to cooperate with baseline survey and long-term follow-up (i.e., expected to reside in the study area during the follow-up period, without severe cognitive impairment, movement disorders, or other conditions that would interfere with follow-up).

Exclusion Criteria:

• 1.Concomitant other chronic liver diseases: viral hepatitis (hepatitis B, hepatitis C, etc.), alcoholic liver disease (alcohol intake ≥140 g/week for males, ≥70 g/week for females), autoimmune liver disease, drug-induced liver injury, liver cirrhosis, liver cancer, etc.;

  2.Concomitant severe cardiovascular or cerebrovascular disease, end-stage renal disease (CKD stage 5), malignant tumor, severe infection, etc., with an estimated life expectancy <5 years;

  3.Current use of medications that may significantly affect liver metabolism or glucose metabolism (other than routine glucose-lowering, lipid-regulating, or hepatoprotective agents) that cannot be adjusted;

  4.Pregnant or lactating women, or those planning to become pregnant in the near term;

  5.Severe mental illness or cognitive impairment that prevents cooperation with surveys and follow-up;

  6.Refusal to sign informed consent, or inability to comply with study procedures.

Adult patients (≥18 years) with type 2 diabetes mellitus and metabolic dysfunction-associated steatotic liver disease (MASLD) recruited from outpatient and inpatient departments of a tertiary hospital, who are able to complete long-term follow-up and provide informed consent.