Abstract Body (Do not enter title and authors here): Introduction:
Diabetes mellitus (DM) and atrial myopathy play a key role in the pathophysiology of heart failure with preserved ejection fraction. However, data on the impact of DM on atrial function remain limited and inconclusive, mostly derived from small studies.

Research Question:
Is DM and the degree of glycemic control associated with impaired atrial function, as assessed by echocardiographic parameters and endocrine markers?

Methods:
This retrospective study included patients from a tertiary hospital, stratified into four glycemic groups: (1) non-diabetic; (2) HbA1c 6–7.5%; (3) HbA1c 7.5–9%; and (4) HbA1c >9%. Propensity score matching (PSM) was performed based on age, sex, hypertension, atrial fibrillation, body mass index, and chronic kidney disease. Atrial function was assessed by echocardiography, including indexed left atrial volume (LAVI) and left atrial strain in the reservoir (LAS-r), conduit (LAS-cd), and contraction (LAS-ct) phases. NT-proBNP levels were also measured. Long-term outcomes included all-cause mortality, incident atrial fibrillation, and thromboembolic events. A p-value < 0.05 was considered statistically significant, with 95% confidence intervals reported.

Results:
After PSM, 248 patients were included: 124 (50%) non-diabetic, 68 (27.4%) with DM and HbA1c 6–7.5%, 32 (12.9%) with HbA1c 7.5–9%, and 24 (9.7%) with HbA1c >9%. Mean age across groups was 64.2, 61.8, 61.1, and 62.6 years, respectively; 155 (62.5%) were women, and mean BMI was 34.1 kg/m2. Hypertension prevalence ranged from 90.3% to 91.7% (Figure 1). No significant differences were found in the use of ACE inhibitors, ARBs, statins, or beta-blockers. SGLT2 inhibitor use was more frequent among patients with DM and HbA1c <9%. There were no significant differences in LAVI (p=0.56), LAS-r (p=0.98), LAS-cd (p=0.32), or LAS-ct (p=0.60). NT-proBNP levels were also similar across groups (p=0.978) (Figure 2 and Figure 3). At 2-year follow-up, there were no documented cases of atrial fibrillation, and no significant differences in mortality or thromboembolic events among groups.

Conclusion:
In this PSM cohort comparing patients with DM across varying glycemic control levels to non-diabetic individuals, no significant differences were observed in left atrial volume or function by echocardiography. Likewise, no differences were found in all-cause mortality, atrial fibrillation, or thromboembolic events.