The Relationship Between Increased Ratio of Visceral-to-Subcutaneous Fat Area and Renal Outcome in Chinese Adults With Type 2 Diabetes and Diabetic Kidney Disease

Sagittal abdominal diameter: A novel and potentially superior indicator than waist circumference for diagnosis of central obesity, based on evidence from multiple data sources

BACKGROUND AND AIMS

Our previous research reported a visceral fat area (VFA) estimation equation primarily based on sagittal abdominal diameter (SAD), demonstrating favorable performance compared to traditional Waist Circumference (WC)-based equations. While WC is widely used for central obesity measurement, its accuracy needs improvement. This study aims to investigate whether SAD has advantages over WC in diagnosing central obesity and to determine the optimal cut-off values for diagnosis.

METHODS

This cross-sectional, retrospective cohort study analyzed 6762 individuals from NHANES (2011-2016) and 701 from Chinese health examinations (2023). ROC curve analysis compared AUC of different indicators in identifying two or more non-adipose components of Metabolic Syndrome (MetS).

RESULTS

SAD exhibited the strongest correlation with VFA and demonstrated the strongest associations with most metabolic parameters compared to WC and BMI. Furthermore, compared with WC, SAD had significantly higher AUC values in diagnosing two or more non-adipose components of MetS, with the difference being significant in the NHANES database population (all p < 0.001). The optimal SAD cut-off value was approximately 21.0 cm for both genders and populations, with MetS prevalence increasing rapidly at SAD≥22.0 cm. Subgroup analysis of NHANES revealed variations in optimal SAD cut-off values: Other Races (23.7 cm), Non-Hispanic Black females (18.8 cm), and other subgroups (20.0-22.0 cm).

CONCLUSION

SAD demonstrates higher efficacy than WC in diagnosing central obesity, suggesting its suitability for assessing central obesity. Additionally, SAD shows potential for a unified diagnostic cut-off value across genders and regions.

New sagittal abdominal diameter and transverse abdominal diameter based equations to estimate visceral fat area in type 2 diabetes patients

OBJECTIVE

Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) are considered gold standards for measuring visceral fat area (VFA). However, their relatively high prices and potential radiation exposure limit their widespread use in clinical practice and everyday life. Therefore, our study aims to develop a VFA estimated equation based on sagittal abdominal diameter (SAD) and transverse abdominal diameter (TAD) using anthropometric indexes. To the best of our knowledge, there have been limited studies investigating this aspect thus far.

METHODS

This study was designed as a cross-sectional, retrospective cohort survey. A total of 288 patients (167 males and 121 females) aged 18-80 with type 2 diabetes (T2D) were consecutively collected from a multicenter hospital, and VFA was measured by CT. Subsequently, variables highly correlated with VFA were screened through general linear correlation analysis. A stepwise regression analysis was then conducted to develop a VFA estimated equation. Discrepancies between the estimated and actual VFA values were assessed using the Bland-Altman method to validate the accuracy of the equation.

RESULTS

In the female T2D population, triglyceride (TG), SAD, TAD were found to be independently correlated with VFA; in the male T2D population, BMI, TG, SAD and TAD showed independent correlations with VFA. Among these variables, SAD exhibited the strongest correlation with VFA (r = 0.83 for females, r = 0.88 for males), followed by TAD (r = 0.69 for females, r = 0.79 for males). Based on these findings, a VFA estimated equation was developed for the T2D population: VFA (male) =-364.16 + 15.36*SAD + 0.77*TG + 9.41*TAD - 5.00*BMI (R2 = 0.75, adjusted R2 = 0.74); VFA(female)=-170.87 + 9.72*SAD-24.29*(TG^-1) + 3.93*TAD (R2 = 0.69, adjusted R2 = 0.68). Both models demonstrated a good fit. The Bland-Altman plot indicated a strong agreement between the actual VFA values and the estimated values, the mean differences were close to 0, and the majority of differences fell within the 95% confidence interval.

CONCLUSIONS

In the T2D population, a VFA estimated equation is developed by incorporating SAD and TAD along with other measurement indices. This equation demonstrates a favorable estimated performance, suggesting to the development of novel and practical VFA estimation models in the future study.

Abdominal adipose tissue and type 2 diabetic kidney disease: adipose radiology assessment, impact, and mechanisms

Diabetic kidney disease (DKD) is a significant healthcare burden worldwide that substantially increases the risk of kidney failure and cardiovascular events. To reduce the prevalence of DKD, extensive research is being conducted to determine the risk factors and consequently implement early interventions. Patients with type 2 diabetes mellitus (T2DM) are more likely to be obese. Abdominal adiposity is associated with a greater risk of kidney damage than general obesity. Abdominal adipose tissue can be divided into different fat depots according to the location and function, including visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), perirenal adipose tissue (PAT), and renal sinus adipose tissue (RSAT), which can be accurately measured by radiology techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI). Abdominal fat depots may affect the development of DKD through different mechanisms, and radiologic abdominal adipose characteristics may serve as imaging indicators of DKD risk. This review will first describe the CT/MRI-based assessment of abdominal adipose depots and subsequently describe the current studies on abdominal adipose tissue and DKD development, as well as the underlying mechanisms in patients of T2DM with DKD.

The impact of obesity on cardiovascular and kidney outcomes in patients with chronic kidney disease and type 2 diabetes treated with finerenone: Post hoc analysis of the FIDELITY study

AIM

To assess the effect of finerenone on the risk of cardiovascular and kidney outcomes in patients with chronic kidney disease and type 2 diabetes, with and without obesity.

MATERIALS AND METHODS

A post hoc analysis of the prespecified pooled FIDELITY dataset assessed the association between waist circumference (WC), composite cardiovascular and kidney outcomes, and the effects of finerenone. Participants were stratified by WC risk groups (representing visceral obesity) as low-risk or high-very high-risk (H-/VH-risk).

RESULTS

Of 12 986 patients analysed, 90.8% occupied the H-/VH-risk WC group. Incidence of the composite cardiovascular outcome was similar between finerenone and placebo in the low-risk WC group (hazard ratio [HR] 1.03; 95% confidence interval [CI], 0.72-1.47); finerenone reduced the risk in the H-/VH-risk WC group (HR 0.85; 95% CI, 0.77-0.93). For the kidney outcome, the risk was similar in the low-risk WC group (HR 0.98; 95% CI, 0.66-1.46) and reduced within the H-/VH-risk WC group (HR 0.75; 95% CI, 0.65-0.87) with finerenone versus placebo. There was no significant heterogeneity between the low-risk and H-/VH-risk WC groups for cardiovascular and kidney composite outcomes (P interaction = .26 and .34, respectively). The apparent greater benefit of finerenone on cardiorenal outcomes but lack of significant heterogeneity observed in H-/VH-risk WC patients may be because of the small size of the low-risk group. Adverse events were consistent across WC groups.

CONCLUSION

In FIDELITY, benefits of finerenone in lowering the risk of cardiovascular and kidney outcomes were not significantly modified by patient obesity.

Visceral adiposity in cirrhosis: Association with disease severity and impact of liver transplantation

BACKGROUND

Changes in adipose tissue distribution in liver cirrhosis are poorly characterized and may affect clinical outcomes.

METHODS

Adult liver transplant (LT) January 2008-August 2017 recipients with abdominal MRI within 6 months pre-LT were retrospectively assessed. Visceral adipose tissue, subcutaneous adipose tissue, and skeletal muscle area (cm2) were determined at L3. Visceral-to-subcutaneous adipose tissue ratio (VSR) was used to define relative adipose distribution, stratified by sex. Correlation was tested with Pearson. Body composition measures were compared by Child-Turcotte-Pugh (CTP) class, before and after LT, and evaluated as predictors of clinical outcomes.

RESULTS

A total of 318 patients were studied. Mean age was 56 years, 33.64% were female, and 47.80% had CTP C cirrhosis. CTP C was associated with a 0.42-point increase in VSR compared with CTP A (95% CI = 0.13-0.71, p < 0.01), adjusting for age, sex, diabetes, and HCC. Among the 79 (24.84%) patients with repeat MRI 1-2 years after LT, VSR significantly improved from before LT (1.31 vs. 0.95, p < 0.01). In adjusted analysis, CTP C was associated with a 0.86-point decrease in post-LT VSR compared with pre-LT VSR (95% CI = -1.27 to -0.44, p < 0.01). Body mass index poorly correlated with VSR before and after LT. Elevated pre-LT VSR trended toward an association with a 7.17-point decrease in pre-LT glomerular filtration rate (95% CI = -14.35 to -0.02, p = 0.05), adjusting for CTP C, age, sex, diabetes, hypertension, pre-LT sarcopenia, and hepatocellular carcinoma. Elevated pre-LT VSR did not affect 3-year post-LT mortality (log-rank p = 0.24).

CONCLUSIONS

Poorly represented by body mass index, visceral adiposity is increased in cirrhosis and is associated with CTP class. However, this adipose redistribution may be modifiable by LT.

Serum triglyceride glucose index is a valuable predictor for visceral obesity in patients with type 2 diabetes: a cross-sectional study

BACKGROUND

Since the triglyceride glucose (TyG) index can reflect insulin resistance, it has been proven to be an efficient predictor of glycolipid-metabolism-related diseases. Therefore, this study aimed to investigate the predictive value of the TyG index for visceral obesity (VO) and body fat distribution in patients with type 2 diabetes mellitus (T2DM).

METHODS

Abdominal adipose tissue characteristics in patients with T2DM, including visceral adipose area (VAA), subcutaneous adipose area (SAA), VAA-to-SAA ratio (VSR), visceral adipose density (VAD), and subcutaneous adipose density (SAD), were obtained through analyses of computed tomography images at the lumbar 2/3 level. VO was diagnosed according to the VAA (> 142 cm² for males and > 115 cm² for females). Logistic regression was performed to identify independent factors of VO, and receiver operating characteristic (ROC) curves were used to compare the diagnostic performance according to the area under the ROC curve (AUC).

RESULTS

A total of 976 patients were included in this study. VO patients showed significantly higher TyG values than non-VO patients in males (9.74 vs. 8.88) and females (9.59 vs. 9.01). The TyG index showed significant positive correlations with VAA, SAA, and VSR and negative correlations with VAD and SAD. The TyG index was an independent factor for VO in both males (odds ratio [OR] = 2.997) and females (OR = 2.233). The TyG index ranked second to body mass index (BMI) for predicting VO in male (AUC = 0.770) and female patients (AUC = 0.720). Patients with higher BMI and TyG index values showed a significantly higher risk of VO than the other patients. TyG-BMI, the combination index of TyG and BMI, showed significantly higher predictive power than BMI for VO in male patients (AUC = 0.879 and 0.835, respectively) but showed no significance when compared with BMI in female patients (AUC = 0.865 and 0.835, respectively).

CONCLUSIONS

. TyG is a comprehensive indicator of adipose volume, density, and distribution in patients with T2DM and is a valuable predictor for VO in combination with anthropometric indices, such as BMI.

GLP-1 receptor agonist, liraglutide, protects podocytes from apoptosis in diabetic nephropathy by promoting white fat browning

Glucagon like peptide-1 receptor agonists (GLP-1RAs) belong to the class of incretin drugs. Incretin is a hormone secreted into blood by intestinal cells after food stimulation that induces insulin secretion. Liraglutide is a long-acting GLP-1RA that can reduce blood pressure, blood lipids, and inflammation. Previous studies showed that liraglutide can promote white fat browning and improve renal outcomes in patients with type 2 diabetes mellitus. However, no studies have linked white fat browning to kidney damage. The objective of this study was to investigate the effects of liraglutide-induced white fat browning on podocyte apoptosis in diabetic nephropathy. We also aimed to determine whether podocytes express glucagon like peptide-1 receptor (GLP-1R) and if liraglutide directly affects podocytes via GLP-1R. We assessed fat and renal function in db/db and wild-type mice and the effects of adipocyte conditioned medium on cultured podocytes. Liraglutide (400 mg/kg/d) was subcutaneously injected for 8 weeks. Liraglutide promoted white fat browning in vivo. During adipogenic differentiation of 3T3-L1 cells in vitro, liraglutide also upregulated expression of peroxisome proliferator-activated receptor γ coactivator-1 alpha (PGC1α) and uncoupling protein 1 (UCP1), which can induce white fat browning in vitro. Furthermore, we found that supernatant from 3T3-L1 cells stimulated by liraglutide reduced podocyte apoptosis. The inhibitory effect of liraglutide on apoptosis was eliminated by exogenous TNF-α. Finally, podocytes express GLP-1R. In vivo and in vitro studies showed that the apoptosis of podocytes in diabetic nephropathy may be related to the effect of liraglutide on promoting white lipid browning. Similarly, liraglutide may directly affect podocytes via GLP-1R.

Kidney failure risk in type 1 vs. type 2 childhood-onset diabetes mellitus

BACKGROUND

Diabetic kidney disease (DKD) is becoming increasingly common among children. We aimed to estimate the risk of end-stage renal disease (ESKD) and mortality among adolescents with type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM) and normal renal function compared with non-diabetics. We hypothesized that childhood onset T1DM vs. T2DM would be associated with a different risk profile for developing ESKD and its complications.

METHODS

A nationwide, population-based, retrospective cohort study, including 1,500,522 adolescents examined for military service between 1967 and 1997, which were classified according to the presence and type of diabetes. Data were linked to the Israeli ESKD registry. Cox proportional-hazards models were used to estimate the hazard ratio (HR) for ESKD.

RESULTS

At study enrolment, 1183 adolescents had T1DM and 196 had T2DM. ESKD developed in 2386 non-diabetic individuals (0.2%) compared with 72 individuals (6.1%) with T1DM and 8 individuals (4.1%) with T2DM. Participants with T1DM were younger at ESKD onset than participants with T2DM (median age, 36.0 vs. 40.5 years, P < 0.05). In a multivariate model adjusted for age, sex, paternal origin, enrollment year, BMI, and blood pressure, T1DM and T2DM were associated with HR of 36.4 (95% CI 28.3-46.9) and 19.3 (95% CI 9.6-38.8) for ESKD, respectively. Stratification according to sex, ethnicity, immigration, and socioeconomic status did not materially change the HR. During the follow-up period, mortality rates were higher in T2DM as compared with T1DM and controls (8.7 %, 2.2%, and 2.7% respectively).

CONCLUSIONS

T1DM and T2DM in adolescents with normal renal function confer a significantly increased risk for ESKD. T1DM is associated with younger age at ESKD onset while T2DM is associated with higher mortality rate.

Association of the ratio of visceral-to-subcutaneous fat volume with renal function among patients with primary aldosteronism

Patients with primary aldosteronism have a higher risk of chronic kidney disease. Visceral fat tissue is hypothesized to stimulate the adrenal glands to overproduce aldosterone, and aldosterone promotes visceral fat tissue to produce inflammatory cytokines. However, it is unclear whether the volume of accumulated visceral fat tissue is associated with renal impairment among patients with hyperaldosteronism. We conducted a single-center cross-sectional study to assess the association between the estimated glomerular filtration rate and the ratio of the visceral-to-subcutaneous fat volume calculated by computed tomography. One hundred eighty patients with primary aldosteronism were enrolled. The mean ± SD age was 52.7 ± 11.0 years, and 60.0% were women. The ratio of visceral-to-subcutaneous fat volume was highly correlated with the estimated glomerular filtration rate (r = 0.49, p < 0.001). In multiple linear regression models, the ratio of visceral-to-subcutaneous fat tissue volume was significantly associated with the estimated glomerular filtration rate (estimates: -4.56 mL/min/1.73 m² per 1-SD), and there was an interaction effect between the plasma aldosterone concentration and the ratio of visceral-to-subcutaneous fat volume (p < 0.05). The group with a higher plasma aldosterone concentration exhibited a steeper decline in eGFR than the lower plasma aldosterone concentration group when the ratio increased. The ratio of visceral-to-subcutaneous fat tissue volume was an independent risk factor for renal dysfunction. This association increased in the presence of a high plasma aldosterone concentration. Clinicians should pay attention to the ratio of visceral-to-subcutaneous fat tissue volume and encourage primary aldosteronism patients to improve their lifestyle in addition to treating renin-aldosterone activity.

Visceral to subcutaneous fat ratio as an indicator of a ≥30% eGFR decline in chronic kidney disease

Whether the visceral-to-subcutaneous fat ratio (V/S ratio) is associated with renal prognosis in patients with chronic kidney disease (CKD) remains unclear. Furthermore, little is known about the effect of sex and the absolute amount of visceral fat accumulation such as visceral fat area (VFA) ≥100 cm² on the V/S ratio in relation to renal prognosis. In this study, 200 patients with CKD were evaluated for renal prognosis. Survival analyses and logistic regression analyses were conducted, generating time-series pseudo-R² values. The mean and percent change of the pseudo-R² values from the 6^th year to the 10^th year (6Y–10Y Mean and 6Y–10Y Change, respectively) were calculated for determining the cut-off points for the medium-term renal prognosis. Multivariate Cox regression analysis revealed that the V/S ratio was significantly associated with renal outcomes and that the VFA category (VFA ≥ 100 cm²) had significant interactions with the V/S ratio regarding renal prognosis. The hazard ratio (HR) of the V/S ratio was higher in the sub-cohort of VFA < 100 cm² than in the sub-cohort of VFA ≥ 100 cm² (HR: 6.42 vs. 1.00). Regarding sex differences, a strong association was noted between the V/S ratio and renal prognosis in women but not in men (HR: 2.40 vs. 1.10). On the other hand, 6Y–10Y Mean of the pseudo-R² values indicated differences in the cut-off points of the V/S ratio between men and women (V/S ratio: 0.75 vs. 0.5). Our findings indicate that it may be clinically meaningful to consider the differences in sex and the amount of VFA ≥100 cm² for the V/S ratio in relation to renal outcomes in patients with CKD. The 6Y–10Y Mean of the pseudo-R² values contributed to determining the cut-off points of the V/S ratio according to the sex difference.

Effects of age and sex on the relationship between body fat area and kidney events in patients with chronic kidney disease

We examined the effects of age and sex on the relationship between body fat area and kidney events. We included 367 chronic kidney disease patients between 2011 and 2017. Patients' median age was 73.0 years; 262 (71.4%) patients were male. The median estimated glomerular filtration rate was 20.2 mL/min/1.73 m² . During the observation period, 187 patients developed kidney events. In males aged <75 years, high subcutaneous fat area was a risk factor for kidney events (hazard ratio: 1.06, 95% CI: 1.02-1.11). In females aged <75 years, high visceral fat area reduced kidney events (hazard ratio: 0.83, 95% CI: 0.71-0.97). In males and females ≥75 years, visceral fat area and subcutaneous fat area were not associated with kidney events. Body fat area was not a risk factor for chronic kidney disease progression in elderly patients. Opposite effects, in sex-related body fat and kidney events, were shown in young patients.

Visceral-to-Subcutaneous Abdominal Fat Ratio Is Associated with Nonalcoholic Fatty Liver Disease and Liver Fibrosis

BACKGROUND

We evaluated the association of visceral-to-subcutaneous fat ratio (VSR) with nonalcoholic fatty liver disease (NAFLD) and advanced fibrosis degree based on noninvasive serum fibrosis markers in the general population with NAFLD.

METHODS

This is a cross-sectional study, in 7,465 Korean adults who underwent health screening examinations. NAFLD was defined as fatty liver detected on ultrasonography, and visceral and subcutaneous abdominal fat was measured using computed tomography. We predicted fibrosis based on the fibrosis-4 (FIB-4) score and aspartate aminotransferase-to-platelet ratio index (APRI) and categorized the risk for advanced fibrosis as low, indeterminate, or high.

RESULTS

The multivariable-adjusted prevalence ratios for indeterminate to high risk of advanced fibrosis based on FIB-4, determined by comparing the second, third, and fourth quartiles with the first quartile of VSR, were 3.38 (95% confidence interval [CI], 0.64 to 17.97), 9.41 (95% CI, 1.97 to 45.01), and 19.34 (95% CI, 4.06 to 92.18), respectively. The multivariable-adjusted prevalence ratios for intermediate to high degree of fibrosis according to APRI also increased across VSR quartiles (5.04 [95% CI, 2.65 to 9.59], 7.51 [95% CI, 3.91 to 14.42], and 19.55 [95% CI, 9.97 to 38.34], respectively). High VSR was more strongly associated with the prevalence of NAFLD in nonobese subjects than in obese subjects, and the associations between VSR and intermediate to high probability of advanced fibrosis in NAFLD were stronger in obese subjects than in nonobese subjects.

CONCLUSION

High VSR values predicted increased NAFLD risk and advanced fibrosis risk with NAFLD, and the predictive value of VSR for indeterminate to high risk of advanced fibrosis was higher in obese subjects than in nonobese subjects.