Diabetes is an endocrine disorder characterized by hyperglycemia, with T2DM being the most prevalent form. According to the International Diabetes Federation (IDF), 537 million adults worldwide had diabetes in 2021, and the number is projected to increase to 643 million by 2030.1 Research shows that the risk of CVD in diabetic patients is significantly higher than that in the general population, and the mortality rate from CVD is twice that in healthy individuals.2 Therefore, early detection and prevention of diabetes-related cardiovascular diseases have become core goals in the management of diabetes.

MAU is an early indicator of diabetic nephropathy and an important predictor of cardiovascular disease in diabetic patients. The presence of MAU is usually the first sign of kidney dysfunction in diabetes, and its progression may increase the risk of adverse cardiovascular events.3 Approximately 7.3% of T2DM patients exhibit MAU at the time of initial diagnosis, and this proportion rises to 17.3% after five years.4 The Heart Outcomes Prevention Evaluation (HOPE) study showed that for each 0.4 mg/mmol increase in the urine albumin-to-creatinine ratio (UACR), the risk of cardiovascular events increases by 5.9%.5 Moreover, MAU has been confirmed as an independent risk factor for coronary artery disease and is significantly associated with the extent of atherosclerosis.6

LVDD refers to a reduction in the active relaxation ability and compliance of the left ventricle, leading to impaired left ventricular filling during diastole. It is an important stage in the occurrence and progression of various CVD.7 In patients with T2DM, clinical evidence of left ventricular remodeling and dysfunction often appears before the onset of overt CVD, and LVDD is considered one of the earliest markers of myocardial dysfunction.8, 9 Therefore, early detection of LVDD and timely intervention may help reduce the risk of developing CVD in T2DM patients.

In clinical practice, the assessment of cardiac diastolic function typically relies on transthoracic echocardiography (TTE). However, this method is highly dependent on the operator's experience and technical proficiency and may be influenced by certain confounding factors. In contrast, electrocardiography (ECG) is widely used in the diagnosis and evaluation of CVD due to its simplicity, cost-effectiveness, and reliability. fQRS is a novel electrocardiographic marker, first proposed by Das et al. in 2006,10 and is frequently observed in leads corresponding to the areas supplied by coronary arteries. Studies have shown that fQRS is a marker of myocardial scarring and myocardial fibrosis, and can be used to predict various adverse cardiovascular events.11

Currently, there is limited research on the relationship between fQRS and MAU in patients with T2DM. This study aims to explore whether fQRS and MAU are associated with LVDD in T2DM patients, and further to examine whether the association between fQRS and LVDD is consistent across different MAU statuses. The goal is to provide new insights for early diagnosis and intervention of CVD, as well as personalized treatment decisions.