Heart rate nondipping pattern and left atrial remodeling as a marker of cardiac target organ damage in patients with type 2 diabetes

Background The heart rate (HR) nondipping pattern reflects autonomic dysfunction and has been associated with adverse cardiovascular outcomes. However, its relationship with subclinical target organ damage (TOD) in patients with type 2 diabetes (T2D) has been poorly studied. The aim of this study was to assess the association between the HR nondipping pattern and TOD in this population. Methods Cross-sectional study including patients with T2D without cardiovascular disease, chronic kidney disease, or beta-blocker treatment. Ambulatory blood pressure monitoring, echocardiography, and urinary albumin-to-creatinine ratio assessment were performed. HR nondipping was defined as a nocturnal HR decline < 10%. Markers of TOD included left atrial area (LAA), indexed LAA, left ventricular hypertrophy (LVH), and albuminuria. Multivariable linear regression models and sensitivity analyses were performed, including collinearity analysis. A sensitivity analysis excluding patients receiving antihypertensive treatment. Results A total of 201 patients with T2D were included (64.7% women; age 54.8 ± 9.4 years; diabetes duration 6.97 ± 7.03 years), of whom 44.8% exhibited an HR nondipping pattern. These patients showed greater LAA (19.98 ± 3.75 vs. 18.61 ± 3.36 cm²; p = 0.007) and indexed LAA (10.50 ± 2.39 vs. 9.73 ± 1.69 cm²/m²; p = 0.008), with no differences in LVH or albuminuria. In multivariable analysis, HR nondipping was independently associated with higher indexed LAA (B = 0.68; 95% CI: 0.13–1.24; p = 0.016). No significant collinearity was observed. Results remained consistent in the sensitivity analysis. Conclusions In patients with T2D, the HR nondipping pattern was independently associated with greater indexed LAA.