Waist circumference is strongly associated with renal resistive index in normoalbuminuric patients with type 2 diabetes

Perirenal fat and chronic kidney disease in type 2 diabetes: the mediation role of afferent arteriolar resistance

AIM

Perirenal fat (PRF) is an independent predictor for chronic kidney disease (CKD) in type 2 diabetes mellitus (T2DM) patients. Previous studies speculated that PRF may promote renal dysfunction through affecting renal hemodynamics. To verify this hypothesis, we studied the relationship between PRF and renal hemodynamics in T2DM.

METHODS

91 T2DM patients were included. PRF thickness (PRFT) was measured by magnetic resonance imaging. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were determined by renal dynamic imaging. Renal vascular resistance (RVR), glomerular hydrostatic pressure (PGLO), afferent (RA) and efferent (RE) arteriolar resistance were calculated by Gomez equations. Multiple linear regression was used to determine the relationship between PRFT and renal hemodynamics. Mediation analysis was conducted to estimate the mediation effects of renal hemodynamics on the relationship between PRF and CKD.

RESULTS

All patients were divided into three groups according to the tertiles of PRFT. Compared with patients in tertile 1, GFR and ERPF were significantly decreased in patients in tertile 3, while RVR and RA were significantly increased. PRFT was negatively correlated with GFR, ERPF and PGLO, and positively correlated with RVR and RA after adjustment for sex, age, visceral adipose tissue and treatments with ACE inhibitors/angiotensin receptor blockers and sodium-glucose cotransporter protein-2 inhibitors. Moreover, RVR and RA mediated the effect of PRF on GFR, with a mediated proportion of 29.1% and 41.4% respectively.

CONCLUSION

In T2DM patients, PRF was negatively correlated with GFR, and positively correlated with RA. RA mediated the relationship between PRF and CKD.

Type 2 diabetes albuminuric and non-albuminuric phenotypes have different morphological and functional ultrasound features of diabetic kidney disease

AIMS

Whether different diabetic kidney disease (DKD) phenotypes recognise differences in morphological and vascular properties of the kidney is still unexplored. We evaluated the potential role of kidney ultrasonography in differentiating DKD phenotypes in subjects with type 2 diabetes.

MATERIALS AND METHODS

This is a cross-sectional, single-centre study. Total (TRV) and parenchymal renal volumes (PRV) were calculated by applying the ellipsoid formula for conventional (2D) ultrasonography and with manual segmentation for 3D ultrasonography, and then adjusted for body surface area (aTRV, aPRV). Renal resistive index (RI) was contextually determined. DKD phenotypes have been defined based on increased urinary albumin-to-creatinine ratio (ACR >30 mg/g) and/or reduced eGFR (<60 ml/min/1.73 m² ). Recruitment was planned to have groups of the same size.

RESULTS

Among 256 subjects, 26.2% had No-DKD, 24.6% increased albuminuria only (Alb⁺ ), 24.2% non-albuminuric DKD (Alb^- DKD), and 25.0% albuminuric DKD (Alb⁺ DKD). Compared to No-DKD, RI was significantly higher in all DKD phenotypes, being the highest in Alb⁺ DKD, and with a significant trend of RI > 0.70 to increase across phenotypes. In comparison with No-DKD, both 2D and 3D volumes were increased in Alb⁺ and significantly reduced in Alb^- DKD as well as in Alb⁺ DKD, with significantly lower volumes in Alb^- DKD as compared to Alb⁺ DKD at the same reduced levels of eGFR. In adjusted regressions, compared to No-DKD, RI was associated with Alb⁺ ; both RI and aPRV3D were associated with Alb⁺ DKD; only aPRV3D with Alb^- DKD. Compared to No-DKD, Receiver Operating Characteristic curve analyses, designed taking into account conventional risk factors, showed that US parameters did not ameliorate the characterisation of Alb⁺ and Alb⁺ DKD, while aPRV3D significantly improved the phenotyping of Alb^- DKD.

CONCLUSIONS

As a novel information, we reported that, in type 2 diabetes, the emerging normoalbuminuric DKD phenotype showed reduced TRVs and PRVs even when compared, at similarly reduced eGFR levels, with Alb⁺ DKD opening. In perspective, these findings suggest a possible role of imaging for better discrimination of DKD phenotypes in clinical practice.

The magnitude of obesity and metabolic syndrome among diabetic chronic kidney disease population: A nationwide study

Background

Although the prevalence of obesity and metabolic syndrome (MetS) among dialysis patients has been exceeding than general population, little is known regarding obesity and MetS in non-dialysis chronic kidney disease (CKD). We aimed to find the magnitude of obesity and MetS and their associations with impaired renal function among type 2 diabetes mellitus (T2DM) patients.

Methods

A national survey of T2DM patients was collected in the Thai National Health Security Office database during 2014–5. The sampling frame was designated as distinct geographic regions throughout the country. A stratified two-stage cluster sampling was used to select the study population. Anthropometry and 12-hour fasting blood samples were obtained by trained personnel. BMI of ≥25 kg/m² was classified as obesity. MetS was defined as having elevated waist circumference (>90 and >80 cm in men and women, respectively) plus any two of the followings: triglyceride ≥150 mg/dL, HDL-C <40 in men or <50 mg/dL in women, blood pressure ≥130/85 mmHg, and fasting blood sugar ≥100 mg/dL. CKD was defined as an impaired renal function (eGFR <60 mL/min/1.73m² according to the CKD-EPI equation). Logistic regression analysis was performed to examine the relationship between obesity and MetS with the presence of CKD.

Results

A total of 32,616 diabetic patients were finally recruited from 997 hospitals. The mean age was 61.5±10.9 years with 67.5% women. Of the participants, 35.4% were CKD patients. The prevalence of obesity was 46.5% in CKD and 54.1% in non-CKD patients with T2DM (p<0.001). In contrast, the prevalence of MetS in CKD patients was higher than their non-CKD counterparts (71.3 vs 68.8%, p<0.001). Moreover, there was an association between the prevalence of MetS with CKD stage from 3a to 5 (70.1, 72.3, 73.4, and 72.7%, respectively, p trend = 0.02). MetS, but not obesity, had a significant association with CKD in T2DM patients after adjusting for age, sex, and comorbidities [OR 1.14; 95% CI 1.06–1.22, p<0.001]. When stratified by each component of MetS, only high serum triglyceride and low HDL-C levels were increased in patients with CKD stage 4 and 5 compared with CKD stage 3 (p<0.001) and had a significant relationship with impaired renal function.

Conclusion

There were relatively high prevalences of both obesity and MetS in T2DM patients. A higher prevalence of MetS, but lower prevalence of obesity, was observed among diabetic CKD group compared with their non-CKD counterparts. MetS, as a surrogate of insulin resistance, appeared to be more important than obesity in the development of impaired renal function in diabetic population.

Relationship Between Individual Components of the Extended-Criteria Donor Definition and the First Post-transplant Kidney Graft Resistance Index, Measured by Doppler Sonography

BACKGROUND

Despite an increasing utilization of kidneys procured from expanded-criteria donors, little is known about the effects of particular expanded-criteria donors definition components, that is, hypertension, increased creatinine prior to procurement, and cerebrovascular cause of death on the kidney graft Doppler parameters measured shortly after transplantation, whose increased values are associated with unfavorable outcomes. Hence, we analyzed the relationship between expanded-criteria donors components and resistance index values measured within 2 to 3 days post-transplant.

MATERIAL AND METHODS

The initial post-transplant resistance index value was measured in 676 consecutive successful first cadaveric kidney graft recipients without delayed graft function or early acute rejection episode. We analyzed resistance index values in 460 patients transplanted with organs from donors <50 years and in 216 recipients with organs from donors >50 years old.

RESULTS

In general, expanded-criteria donors status did not influence the initial resistance index values in the whole study group. Unexpectedly, in older donor groups, both the occurrence of donor hypertension and cerebrovascular cause of death resulted in significantly lower resistance index values in kidney graft recipients (0.73 ± 0.10 vs 0.76 ± 0.11 in the non-hypertension group, P = .013 and 0.74 ± 0.11 vs 0.78 ± 0.10 in the non-cerebrovascular cause of death group, P = .015, respectively). In the Cox proportional regression model for graft survival, cerebrovascular cause of death was increasing the risk of graft loss by 55%, while recipient's age had the opposite effect, decreasing the risk of graft loss by 2% per year.

CONCLUSIONS

Regardless of the limited influence of expanded-criteria donor status on first post-transplant resistance index value, the long-term observation shows moderate but significantly worse kidney graft survival, mostly as a result of the cerebrovascular cause of donor's death.

Increased renal resistive index in type 2 diabetes: Clinical relevance, mechanisms and future directions

Type 2 diabetes is a global health challenge. In type 2 diabetes both microvascular (nephropathy, retinopathy, neuropathy) and macrovascular complications arise. In kidney, renal pathological changes leading to diabetic nephropathy are mainly secondary to atherosclerosis of the intra and extra renal arteries together with microangiopathy of the glomerular capillaries, afferent arterioles and efferent arterioles. Renal resistive index (RRI) is defined as a ratio of the difference between maximum and minimum (end-diastolic) flow velocity to maximum flow velocity derived from the Doppler measurements of main renal and intrarenal (segmental/interlobar) arteries. Renal resistive index is tightly related to renal arteriolosclerosis, and represents an integrated index of arterial compliance, pulsatility and downstream microvascular impedance. In meantime, growing suggest that RRI has also been closely related with atherosclerosis. Most studies performed in type 2 diabetes showed RRI is increased in type 2 diabetes. In this review, we summarize the data regarding RRI with regard to performed studies, pathogenesis and prognosis, especially focusing on type 2 diabetes (T2D). We also review the data regarding the development of metabolic syndrome (MetS) and RRI.

Para- and perirenal fat thickness is an independent predictor of chronic kidney disease, increased renal resistance index and hyperuricaemia in type-2 diabetic patients

BACKGROUND

Many interfering factors may reduce the reliability of waist circumference (WC) measurement in estimating the risk for chronic kidney disease (CKD) associated with obesity. Therefore, we determined the independent associations of para- and perirenal ultrasonographic fat thickness with the main markers of kidney function.

METHODS

A cross-sectional study was performed in 151 type-2 diabetic subjects. Para- and perirenal fat thickness was measured from the inner side of the abdominal musculature to the surface of the kidneys. CKD was defined as eGFR < 60 mL min(-1)1.73 m(-2).

RESULTS

Using both univariate and multivariate regression analyses, eGFR, renal resistance index and uricaemia were best predicted by para- and perirenal fat thickness even when BMI and waist circumference were further added in the statistical model (r(2): 0.366, P = 0.001; r(2): 0.529, P = 0.005; r(2): 0.310, P = 0.026, respectively), whereas waist circumference and BMI did not contribute independently of para- and perirenal fat thickness. Albuminuria was predicted by waist circumference but not by para- and perirenal fat thickness. In subjects with waist circumference above the diagnostic values of metabolic syndrome (48M/59F), eGFR significantly and progressively declined across tertiles of para- and perirenal fat thickness (87.0 ± 27.9 vs 83.5 ± 26.0 vs 62.3 ± 30.6 mL min(-1) 1.73 m(-2), adjusted P < 0.0001) despite comparable waist circumference, and an increasing frequency of CKD was observed across tertiles of subjects with waist circumference both below and above the metabolic syndrome diagnostic values (P < 0.05).

CONCLUSIONS

Para- and perirenal fat thickness is an independent predictor of kidney dysfunction in type-2 diabetes explaining an important proportion of the variance of eGFR, renal resistance index and uricaemia.

Metabolic syndrome predicts new onset of chronic kidney disease in 5,829 patients with type 2 diabetes: a 5-year prospective analysis of the Hong Kong Diabetes Registry

OBJECTIVE

Type 2 diabetes is the leading cause of end-stage renal disease worldwide. Aside from hyperglycemia and hypertension, other metabolic factors may determine renal outcome. We examined risk associations of metabolic syndrome with new onset of chronic kidney disease (CKD) in 5,829 Chinese patients with type 2 diabetes enrolled between 1995 and 2005.

RESEARCH DESIGN AND METHODS

Metabolic syndrome was defined by National Cholesterol Education Program Adult Treatment Panel III criteria with the Asian definition of obesity. Estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Modification of Diet in Renal Disease formula modified for the Chinese population. New onset of CKD was defined as eGFR <60 ml/min per 1.73 m(2) at the time of censor. Subjects with CKD at baseline were excluded from the analysis.

RESULTS

After a median follow-up duration of 4.6 years (interquartile range: 1.9-7.3 years), 741 patients developed CKD. The multivariable-adjusted hazard ratio (HR) of CKD was 1.31 (95% CI 1.12-1.54, P = 0.001) for subjects with metabolic syndrome compared with those without metabolic syndrome. Relative to subjects with no other components of metabolic syndrome except for diabetes, those with two, three, four, and five metabolic syndrome components had HRs of an increased risk of CKD of 1.15 (0.83-1.60, P = 0.407) 1.32 (0.94-1.86, P = 0.112), 1.64 (1.17-2.32, P = 0.004), and 2.34 (1.54-3.54, P < 0.001), respectively. The metabolic syndrome traits of central obesity, hypertriglyceridemia, hypertension, and low BMI were independent predictors for CKD.

CONCLUSIONS

The presence of metabolic syndrome independently predicts the development of CKD in subjects with type 2 diabetes.