High prevalence of asymptomatic left ventricular diastolic dysfunction and its detection among South Asian patients with Type 2 Diabetes Mellitus compared with White Europeans
Authors: Lee C E C , Subramani P , Ananth P , Bhalraam U , Victor C , Venkatesan R , Prathiba V , Anjana R M , Palmer C N A , Struthers A D , Singh J S , Mordi I R , Mohan V , Lang C C 
Published: October 2022

Abstract

Background
Heart failure (HF) is an important manifestation of Type 2 Diabetes (T2D). The development of HF in T2D may be preceded by Stage B HF. Asymptomatic left ventricular impairment, especially left ventricular diastolic dysfunction (LVDD), is a defining early feature of Stage B HF. Detection of Stage B HF is crucial as it provides an opportune target for intervention with cardio-protective therapy to prevent the development of symptomatic HF in T2D. The risk of T2DM is higher in South Asian populations resulting in increased risk of macrovascular and microvascular complications. The prevalence of Stage B HF in South Asian patients with T2DM is not known.

Purpose
(i) To compare the prevalence of Stage B HF in South Asians in India compared with White Europeans in Scotland; (ii) To test the role of NT-proBNP in identifying Stage B HF

Methods
This study involved the comparison between two independently conducted, cross-sectional studies. The patients were asymptomatic patients with T2DM with no prior history of cardiovascular disease from Chennai, India (n=246) and Tayside, Scotland (n=246). All patients underwent transthoracic echocardiogram (echo) examination to detect the presence of structural and functional echo features of Stage B HF: left atrial enlargement (LAE), left ventricular hypertrophy (LVH), LVDD and LV systolic dysfunction (LVSD). Receiver operating curves (ROC) were used to determine the predictive ability of NT-proBNP to predict LAE/LVDD/LVD/LVSD.

Results
The prevalence of Stage B HF was high in South-Asian patients with T2DM (median age of 55 [49, 62] with a high prevalence of LVDD (5% had LVH, 7.3% had LAE, 70% had LVDD and 0% had LVSD (Figure 1B). 10% of the South Asian patients had at least 2 factors contributing to Stage B HF and these patients had higher NT-proBNP titres (703.4 [500.0, 949.2] vs 423.7 [35.0, 754.2], p&lt;0.001). ROC curves show that NT-proBNP can predict these participants with 2 or more echo features [Figure 2B, AUC: 0.7043 (0.6159, 0.7928) p&lt;0.05]. The prevalence of Stage B HF among White Europeans (median age of 67 [61, 72].) was lower compared with South Asian patients: 15% had LVH, 13% had LAE, 19% had LVDD and 2% had LVSD (Figure 1A). 8% of White Europeans had at least 2 factors contributing to Stage B HF and these had higher NT-proBNP titres (368.9 [154.6, 1087.8] vs 186.8 [79.7, 411.5], p=0.02). ROC curves show that NT-proBNP can predict participants with 2 or more factors [Figure 2A, AUC: 0.6399 (0.5122, 0.7676) p&lt;0.05].

Conclusion
Our study has shown that South Asian patients with T2DM have a high prevalence of Stage B HF compared with White Europeans and that the predominant Stage B HF feature is LVDD.
We also found that NTproBNP could potentially be used to detect Stage B HF and help identify at-risk patients for cardio-protective therapy such as SGLT2 inhibitor therapy that has been shown to prevent the development of future HF events.

Funding Acknowledgement
Type of funding sources: None.