Obesity and type 2 diabetes have additive effects on left ventricular remodelling in normotensive patients-a cross sectional study

Abstract

Background: It is unclear whether obesity and type 2 diabetes (T2D), either alone or in combination, induce left ventricular hypertrophy (LVH) independent of hypertension. In the current study, we provide clarity on this issue by rigorously analysing patient left ventricular (LV) structure via clinical indices and via LV geometric patterns (more commonly used in research settings). Importantly, our sample consisted of hypertensive patients that are routinely screened for LVH via echocardiography and normotensive patients that would normally be deemed low risk with no further action required.

Methods: This cross sectional study comprised a total of 353 Caucasian patients, grouped based on diagnosis of obesity, T2D and hypertension, with normotensive obese patients further separated based on metabolic health. Basic metabolic parameters were collected and LV structure and function were assessed via transthoracic echocardiography. Multivariable logistic and linear regression analyses were used to identify predictors of LVH and diastolic dysfunction.

Results: Metabolically healthy normotensive obese patients exhibited relatively low risk of LVH. However, normotensive metabolically non-healthy obese, T2D and obese/T2D patients all presented with reduced normal LV geometry that coincided with increased LV concentric remodelling. Furthermore, normotensive patients presenting with both obesity and T2D had a higher incidence of concentric hypertrophy and grade 3 diastolic dysfunction than normotensive patients with either condition alone, indicating an additive effect of obesity and T2D. Alarmingly these alterations were at a comparable prevalence to that observed in hypertensive patients. Interestingly, assessment of LVPWd, a traditional index of LVH, underestimated the presence of LV concentric remodelling. The implications for which were demonstrated by concentric remodelling and concentric hypertrophy strongly associating with grade 1 and 3 diastolic dysfunction respectively, independent of sex, age and BMI. Finally, pulse pressure was identified as a strong predictor of LV remodelling within normotensive patients.

Conclusions: These findings show that metabolically non-healthy obese, T2D and obese/T2D patients can develop LVH independent of hypertension. Furthermore, that LVPWd may underestimate LV remodelling in these patient groups and that pulse pressure can be used as convenient predictor of hypertrophy status.

Keywords: Echocardiography; Left ventricular diastolic dysfunction; Left ventricular hypertrophy; Obesity; Type 2 diabetes.

Fig. 1

a LV mass/height (g/m^2.7), b RWT, Error bars represented as mean ± SD. c Percentage of subjects with normal LV geometry, eccentric hypertrophy, concentric remodelling or concentric hypertrophy. **p < 0.01, vs same group, different condition; ^ǂǂp < 0.01, vs obese group, same condition; ^××p < 0.01, vs T2D group, same condition

Fig. 2

Normotensive and hypertensive patients grouped based on characterisation of normal LV geometry, eccentric hypertrophy, concentric remodelling and concentric hypertrophy. a LVPWd (cm), b RWT. Data represented as mean ± SEM. ^ǂǂǂp < 0.001 vs normal geometry, ^×××p < 0.001 vs eccentric hypertrophy, ⁺p < 0.05 vs concentric remodelling

Fig. 3

Percentage of normotensive and hypertensive obese, T2D and obese/T2D groups with a normal diastolic function, b grade 1 DD, c grade 2 DD and d grade 3 DD. e Linear regression analysis between RWT and Pulse Pressure (mmHg) in normotensive obese and/or T2D patients, ***p < 0.001 via linear regression analysis. Accounting for sex and age; *p < 0.05 vs same group, different condition, ^ǂp < 0.05, ^ǂǂp < 0.01, ^ǂǂǂp < 0.001 vs obese group, same condition, ^×××p < 0.001 vs T2D group, same condition

Fig. 4

Percentage of metabolically healthy (MH) and metabolically non-healthy (MNH) normotensive with a normal LV geometry, eccentric hypertrophy, concentric remodelling and concentric hypertrophy, b normal diastolic function, c grade 1 DD, d grade 2 DD, and e grade 3 DD. Accounting for sex and age; *p < 0.05y vs MH