Introduction

Obesity is a key predictor of type-2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD), strongly linked to their onset and progression, and has been identified as a critical risk factor for CV issues. Studies till date have used various obesity metrics such as body mass index (BMI), waist circumference (WC), and visceral adiposity index (VAI) to assess the role of obesity, each with its set of pros and cons. BMI is the most commonly used metric but it does not distinguish fat distribution from muscle mass, while WC better reflects abdominal fat—a stronger predictor of CV risk—though it’s not recommended as the sole measure over BMI. The weight-adjusted waist index (WWI) combines waist circumference with body weight, calculated by dividing WC by the square root of weight. This measure integrates the strengths of WC while addressing limitations of BMI, offering a more precise assessment of body fat distribution and muscle mass, and improving evaluation of obesity-related CV and metabolic risks.

Aim

To ascertain the link between the WWI and CV outcomes in patients with T2DM.

Patient Profile

• Patients with T2DM (age: 40-79 yrs, mean age of 62.2 years, median HbA1c of 8.1%).
• All the study participants either had existing CVD or were at an elevated risk for such condi­tions.

Methods

Study Design

• A post hoc analysis of the ACCORD (Action to Con­trol Cardiovascular Risk in Diabetes) and ACCORDION (follow-on) trial.
• The ACCORD was a randomized, multicentre, double-blind clinical trial involving 10,251 patients and treatment monitoring of 5 years with an additional follow up of 3.5 years (ACCORDION).

Outcomes

Primary Outcomes

Secondary Outcomes

Assessments

• The statistical assessments employed SPSS 26.0, R, and EmpowerStats.
• The impact of WWI on CV events was determined using the Cox proportional hazards regression models. 
• Furthermore, restricted cubic splines (RCS) and smooth curve fitting (SCF) models were employed to ascertain the nonlinear association. 
• The integrity of these findings was supported by subgroup and sensitivity analyses.

Results

• The average WWI for the study population was 11.08±0.77, based on the baseline WWI values, study subjects were dis­tributed into four quartiles as follows:
  1. Quartile 1: 10.14 ± 0.36
  2. Quartile 2: 10.82 ± 0.14
  3. Quartile 3: 11.31 ± 0.15
  4. Quartile 4: 12.07 ± 0.45
• Higher WWI quartiles were linked to older age, higher percentage of women and white participants, lower education, less alcohol use, greater likelihood of living alone, and higher depression prevalence.
• Subjects with high WWI also had higher rates of heart failure and CVD, along with increased BMI, glycosylated haemoglobin (HbA1c), and triglyceride levels but decreased height and low-density lipoprotein cholesterol (LDL-C) levels. These subjects used diuretics, angiotensin receptor blockers/angiotensin converting enzyme inhibitors, calcium channel blockers, beta-blockers, insu­lins, and aspirin more frequently than the subjects in the other groups. 
• Subjects in the higher quartiles of WWI showed significant correlation with increased risk for MACE, MSD, CHF and TM with highest quartile showing markedly greater outcomes than the lowest one (p<0.05)
• Over 8.82 years, 17.77% subjects developed MACE, 27.96% MSD, 18.99% died, and 6.80% had CHF. Incidence rose with higher WWI quartiles, peaking at 19.89% in the top quartile. Both TM and CHF risk increased with higher quartiles, underscoring the strong predictive value of WWI for adverse CV outcomes.
• Per standard deviation (SD) increase in WWI corresponded to a 7% higher risk of MACEs (HR: 1.07, 95% CI: 1.02, 1.13), a 9% greater risk of MSD (HR: 1.09, 95% CI: 1.04, 1.13), a 20% greater risk of CHF (HR: 1.20, 95% CI: 1.10, 1.30), and an 11% increase in TM (HR: 1.11, 95% CI: 1.06, 1.17). 
• One-unit decrease in WWI demonstrated a reduced TM risk by 19% (HR = 1.19, 95% CI: 1.11–1.27) and CHF risk by 45% (HR = 1.45, 95% CI: 1.25–1.69). 
• As per RCS and SCF analysis, WWI had a nonlinear correlation with the risks of CHF and TM. 
• The subgroup analyses were segmented by variables such as sex, age (< 60 years or older), race, CVD history, prior instances of hyperlipidemia, hyper­tension, HbA1c levels (< 8.1% and ≥ 8.1%), duration of diabetes (< 10 years and ≥ 10 years), and BMI categories (< 25 kg/m²; ≥25 kg/m² and < 30 kg/m²; and ≥ 30 kg/m²). As per subgroup analyses, WWI more accurately predicted CHF risk in patients with a diabetes duration of less than 10 years. There were no significant differences for the results from other variables. 
• In patients with <10 years of diabetes, as per the fully adjusted models, those in the highest WWI quartile had a 1.72-fold higher CHF risk (HR = 1.72, 95% CI: 1.18–2.50; p = 0.0045). Each 1-SD increase in WWI raised CHF risk by 40% (HR = 1.40, 95% CI: 1.23–1.60; p < 0.0001). These findings highlight the strong predictive accuracy of WWI for CHF in shorter-duration diabetes.
• Sensitivity analyses reinforced the reliability of these results. The integration of WWI into conventional predictive models improved the accuracy of these outcomes.

Conclusions

• The study confirmed a significant and robust cor­relation between WWI and both future adverse CV outcomes and TM in T2DM patients.  WWI outperformed the traditional obesity indices in predictive ability for future CV risk.
• This could provide essential information for CV risk assessment for improving targeted interventions, public health initiatives and man­agement for T2DM patients. 
• Further studies should investigate the clinical efficacy of WWI and validate its significant role in CV risk assessment. 

Nutr J. 2025;24:184. Doi: 10.1186/s12937-025-01251-0.