Background Three-dimensional (3D) speckle tracking echocardiography can identify subclinical diabetic cardiomyopathy without geometric assumption and loss of speckle from out-of-plane motions. There is, however, significant heterogeneity among the previous reports. We performed a systematic review and meta-analysis to compare 3D strain values between adults with asymptomatic, subclinical diabetes mellitus (ie, patients with diabetes mellitus without known clinical manifestations of cardiac disease) and healthy controls. Methods and Results After systematic review of 5 databases, 12 valid studies (544 patients with diabetes mellitus and 489 controls) were eligible for meta-analysis. Pooled means and mean difference (MD) using a random-effects model for 3D global longitudinal, circumferential, radial, and area strain were calculated. Patients with diabetes mellitus had an overall 2.31 percentage points lower 3D global longitudinal strain than healthy subjects (16.6%, 95% CI, 15.7-17.6 versus 19.0; 95% CI, 18.2-19.7; MD, -2.31, 95% CI, -2.72 to -2.03). Similarly, 3D global circumferential strain (18.9%; 95% CI, 17.5-20.3 versus 20.5; 95% CI, 18.9-22.1; MD, -1.50; 95% CI, -2.09 to -0.91); 3D global radial strain (44.6%; 95% CI, 40.2-49.1 versus 48.2; 95% CI, 44.7-51.8; MD, -3.47; 95% CI, -4.98 to -1.97), and 3D global area strain (30.5%; 95% CI, 29.2-31.8 versus 32.4; 95% CI, 30.5-34.3; MD, -1.76; 95% CI, -2.74 to -0.78) were also lower in patients with diabetes mellitus. Significant heterogeneity was noted between studies for all strain directions (inconsistency factor [I2], 37%-78%). Meta-regression in subgroup analysis of studies using the most popular vendor found higher prevalence of hypertension as a significant contributor to worse 3D global longitudinal strain. Higher hemoglobulin A1c was the most significant contributor to worse 3D global circumferential strain in patients with diabetes mellitus. Conclusions Three-dimensional myocardial strain was reduced in all directions in asymptomatic diabetic patients. Hypertension and hemoglobin A1c were associated with worse 3D global longitudinal strain and 3D global circumferential strain, respectively. Registration URL: https://www.crd.york.ac.uk/prospero; unique identifier: CRD42020197825.
Keywords: 3D speckle tracking echocardiography; diabetes mellitus; healthy controls; meta‐analysis; myocardial strain; standardized mean difference; subclinical diabetic cardiomyopathy.