Cardio-renal dysfunction in prediabetes and early type 2 diabetes: insights from myocardial strain and renal Doppler assessment

Prediabetes and early type 2 diabetes mellitus (T2DM) may be accompanied by subclinical cardiac and renal injury before overt disease appears. This study evaluated early cardio-renal dysfunction in prediabetes and early T2DM using myocardial strain imaging and renal Doppler assessment. This cross-sectional study included 180 participants: 60 with prediabetes, 60 with newly diagnosed T2DM (≤ 2 years), and 60 age- and sex-matched healthy controls. Conventional echocardiography and two-dimensional speckle-tracking echocardiography were used to assess left ventricular (LV) function and left atrial (LA) mechanics. Renal vascular resistance was assessed using the Doppler-derived renal resistive index (RRI) and pulsatility index (PI). Glycemic status and albuminuria were evaluated using fasting glucose, oral glucose tolerance testing, HbA1c, and urine albumin-to-creatinine ratio. Compared with controls, participants with prediabetes and T2DM showed early alterations in LV relaxation/filling indices and reduced LA strain. LV ejection fraction was modestly lower, while GLS became progressively less negative across the dysglycemic groups ( p < 0.001), consistent with reduced longitudinal myocardial deformation. Renal resistive index (RRI) and pulsatility index (PI) were significantly increased in the dysglycemic groups. RRI correlated positively with E/e′, linking higher renal vascular resistance with higher estimated LV filling pressure ( r = 0.440, p < 0.001). Prediabetes and early T2DM were associated with subclinical abnormalities in myocardial mechanics and renal vascular indices despite preserved conventional cardiac and renal function. Myocardial strain and renal Doppler measures may provide complementary phenotypic information, but prospective validation is required before routine clinical application.