Cardiovasc Diabetol: Association of abdominal obesity index and risk of cardiovascular events in Chinese people with type 2 diabetes

Background: According to a 2021 report by the International Diabetes Federation, there are about 536 million diabetic patients in the world, while China has 140 million diabetics, ranking first
in the world.
Adults with T2D have twice the risk of developing cardiovascular disease (CVD) and develop it earlier and more severely
than people without type 2 diabetes (T2D).
At the same time, the main cause of hospitalization and death of T2D patients is CVD, which causes a heavy financial medical burden
.
One meta-analysis estimated that CVD affects 32.
2% of patients with T2D and causes death in 9.
9% of patients with T2D (50.
3% of all deaths).

Therefore, it is critical
to identify modifiable CVD risk factors in patients with T2D to provide effective prevention strategies.

Obesity has been identified as a key risk factor
for cardiometabolic disease and premature death.
Body mass index (body mass index) is often used to classify overweight or obesity, but published evidence on the relationship between body mass index and CVD risk in people with T2D is inconsistent
.
Several studies have shown a positive association between body mass index and cardiovascular (CV) events in patients with T2D, but other studies have shown a negative or no association
.
This inconsistent result suggests that BMI is not a perfect obesity estimate because it neither distinguishes between lean mass and total fat mass, nor captures the distribution
of body fat.
Recent evidence suggests that adipose tissue distribution rather than overall obesity is an important factor
in determining CVD risk.
In addition, a growing body of research shows that abdominal fat deposits play a vital role
in cardiometabolic diseases.

Radiographic techniques can accurately assess abdominal obesity, but they are not suitable for extensive epidemiological investigations because they are long-lasting, expensive, and have radiation hazards
.
Therefore, it is necessary to establish reliable and easily accessible indicators to assess abdominal obesity
.
Waist circumference (WC) is a widely used indicator of abdominal obesity, but it has shortcomings
in distinguishing subcutaneous and visceral adipose tissue.
Several new abdominal obesity indices established by combining anthropometric and lipid parameters are considered superior to traditional anthropometric parameters
.
These new indices are the Visceral Fat Index (VAI), Lipid Accumulation Products (LAP), and the Chinese Visceral Fat Index (CVAI).

While some studies suggest that these abdominal obesity indices can predict the onset of CVD in the general population, this issue has rarely been studied
in T2D populations.
To date, only one cross-sectional study has revealed a relationship
between abdominal obesity indicators and macrovascular complications of diabetes.
However, the longitudinal association between these indicators and cardiovascular disease risk in people with T2D remains unclear
.
In addition, although several studies evaluated and compared the predictive performance of abdominal obesity index on chronic disease in different populations, the results were inconsistent
.
Therefore, further research is warranted into which abdominal obesity index is the best predictor
of cardiovascular events in patients with T2D.

Objective: We explored the relationship between baseline abdominal obesity indices (waist circumference, waist circumference, VAI and CVAI) and cardiovascular events in patients with T2D, and compared their risk prediction performance
.

Methods: This study included 2328 patients
with T2D from the Xinjiang multi-ethnic cohort.
Multivariate Cox regression analysis was used to assess the relationship
between abdominal obesity index and cardiovascular events.
C-Statistical, Net Classification Improvement (NRI) Index, and Composite Discrimination Improvement (IDI) Index were used to assess the predictive performance
of each abdominal obesity index.

Results: During a median follow-up period of 59 months, 289 participants experienced cardiovascular events
.
After multivariate adjustment, each increase of 1-SD in WC, VAI, LAP, and CVAI was associated with an increased risk of cardiovascular events in patients with T2D, with adjusted risk ratios (HR) of 1.
57 [95% CI (confidence interval: 1.
39 to 1.
78], 1.
11 (95% CI 1.
06 to 1.
16), 1.
46 (95% CI 1.
36 to 1.
57), and 1.
78 (95% CI 1.
57 to 2.
01),
respectively 。 In subgroup analyses, these positive associations appeared to be stronger
in participants with a body mass index (body mass index) of < 25 kg/m2 compared to overweight/obese participants.
As for predictive performance, CVAI had the largest C-statistic (0.
700, 95% CI 0.
672–0.
728) compared to VAI, Lapp, WC, and Body Mass Index (C-statistic: 0.
535 to 0.
670, all 0.
05 compared).

The CVAI index also showed the largest incremental risk stratification when the abdominal obesity index was added to the basic risk model (C-Statistical: 0.
751 to 0
.
P < 0.
001IDI: 4.
3%, P < 0.
001NRI: 26.
6%, P < 0.
001).

Figure 1 Cardiovascular event rate
in patients with type 2 diabetes mellitus according to the quartile of the abdominal obesity index.
a Waist circumference (WC), B visceral fat index (VAI), C lipid accumulation product (LAP) and D visceral fat index (CVAI)

Table 1 Relationship between baseline abdominal obesity index and cardiovascular events in patients with type 2 diabetes

Fig.
2 Relationship
between abdominal obesity index and cardiovascular events in different subgroups of patients with type 2 diabetes.
In addition to the stratified variables, each subgroup was adjusted
for sex, age, ethnicity, education, smoking status, alcohol consumption status, LDL cholesterol, total cholesterol, fasting blood glucose, systolic blood pressure, diastolic blood pressure, physical activity, antidiabetic medications, and duration of diabetes.
The risk ratio for cardiovascular events is expressed as a 1 SD increase in the abdominal obesity index

Table 2 Predictive performance of abdominal obesity index on cardiovascular events in patients with type 2 diabetes mellitus

Table 3 Improvement in differentiation and risk reclassification of cardiovascular events after increasing the abdominal obesity index

Conclusion: This study provides additional evidence that all abdominal obesity indices are associated with the risk of cardiovascular events and highlights that CVAI may be a valuable indicator of abdominal obesity for identifying high risk
of cardiovascular events in the Chinese population with T2D.
These results suggest that a positive assessment of abdominal obesity may contribute to effective clinical management
in people with diabetes.

Original source:

Qiao T, Luo T, Pei H,et al.
Association between abdominal obesity indices and risk of cardiovascular events in Chinese populations with type 2 diabetes: a prospective cohort study.
Cardiovasc Diabetol 2022 Nov 01; 21(1).