Comparison of CKD-EPI Cystatin C and Creatinine Glomerular Filtration Rate Estimation Equations in Asian Indians

Estimating eGFR using serum creatinine or cystatin C in healthy Vietnamese population

Very few studies worldwide have assessed the estimated glomerular filtration rate (eGFR) using serum cystatin C (ScysC) in comparison to the gold standard measured glomerular filtration rate (mGFR) with a gamma camera technique using 99m-Technetium-Diethylene Triaminepentoacetic Acid (99mTc-DTPA). To determine the eGFR formula with the most accurate estimate of glomerular filtration rate when compared with mGFR in a healthy population in Vietnam. We conducted a cross-sectional descriptive study of more than 100 adults without hypertension. The study subjects were examined for general characteristics and blood biochemistry tests to assess eGFR, and the glomerular filtration rate was measured using 99mTc-DTPA with the Gates technique to record mGFR. The estimated values of the eGFR formula were evaluated and compared with the actual mGFR using 99mTechnetium-DTPA. Serum creatinine (Scr) concentration showed a significant difference between males and females: 0.9 ± 0.1 versus 0.8 ± 0.1 (P < .001), while ScysC concentration did not show this difference. The mGFR in the age groups < 40, 40 to 59, and ≥ 60: 105.0 ± 9.9, 94.8 ± 8.6, and 93.4 ± 10.6, respectively (P < .001). The eGFR-CKD-EPI-cystatin C 2012 formula showed the highest positive correlation with mGFR (ΔGFR = -1.6, R = 0.68, P < .001). eGFR calculated using cystatin C does not require sex adjustment, whereas, for creatinine, sex adjustment is necessary. The eGFR-CKD-Epi-CysC formula showed the lowest difference and a strong correlation with mGFR.

A Review of Specific Biomarkers of Chronic Renal Injury and Their Potential Application in Nonclinical Safety Assessment Studies

A host of novel renal biomarkers have been developed over the past few decades which have enhanced monitoring of renal disease and drug-induced kidney injury in both preclinical studies and in humans. Since chronic kidney disease (CKD) and acute kidney injury (AKI) share similar underlying mechanisms and the tubulointerstitial compartment has a functional role in the progression of CKD, urinary biomarkers of AKI may provide predictive information in chronic renal disease. Numerous studies have explored whether the recent AKI biomarkers could improve upon the standard clinical biomarkers, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio, for predicting outcomes in CKD patients. This review is an introduction to alternative assays that can be utilized in chronic (>3 months duration) nonclinical safety studies to provide information on renal dysfunction and to demonstrate specific situations where these assays could be utilized in nonclinical drug development. Novel biomarkers such as symmetrical dimethyl arginine, dickkopf homolog 3, and cystatin C predict chronic renal injury in animals, act as surrogates for GFR, and may predict changes in GFR in patients over time, ultimately providing a bridge from preclinical to clinical renal monitoring.

The Role of Peer Support Education Model in Management of Glucose and Lipid Levels in Patients with Type 2 Diabetes Mellitus in Chinese Adults

AIMS

To investigate the effect of peer support education model on the levels of glucose and lipids in patients with type 2 diabetes mellitus in China.

METHODS

120 type 2 diabetes mellitus patients (T2DM) were assigned to two groups randomly from December 2016 to October 2017. Group 1 was trained on basic diabetic medical knowledge by a professional medical staff. After 8 weeks of studying, these specially trained patients then trained the patients of Group 2.

RESULTS

It was found that after 3 months of intervention, the levels of fasting blood glucose, triglycerides, glycosylated hemoglobin, total cholesterol, and low-density lipoprotein cholesterol were significantly decreased for the two groups (p < 0.05). However, with the prolongation of time, there were no significant changes in the two groups in the above indices (p > 0.05) after 6 months, and the result was the same after strafing sex, age, and education level. Meanwhile, there was no significant difference in decreasing glucose and lipid level between the two groups' participants (p > 0.05).

CONCLUSION

It was found that both the peer support education model and medical staff education model have a better short-term effect on blood glucose and lipid levels in patients with type 2 diabetes. As there is no difference of effect between the two methods of training, the peer support education model can be widely used in diabetes education.

Cystatin C as a potential predictor of osteoprotegerin levels in healthy men, a cross-sectional, observational study

Background

The aim of the present study is to evaluate serum osteoprotegerin (OPG) and soluble receptor activator of nuclear factor κB ligand (sRANKL) levels in a randomly selected male cohort over 50 years of age and its association with cystatin C, a cysteine proteinase inhibitor that decreases formation of osteoclasts by interfering at a late stage of pre-osteoclast differentiation, apart from being a marker of renal function independent of gender, muscle mass and age; in addition to known predictors such as age, sex hormones, vitamin D, bone mineral density (BMD) and biochemical markers of bone turnover.

Methods

We determined serum OPG and sRANKL levels and examined its relationship with cystatin C, age, osteocalcin, C-terminal telopeptides of type-I collagen, procollagen type 1 amino-terminal propeptide, 25-hydroxyvitamin D, parathyroid hormone, total 17β-estradiol (E2), total testosterone and L1–L4 (LS) and femur neck (FN) BMD data available from 194 (age, range: 51–81 years) randomly selected ambulatory men belonging to the HunMen cohort.

Results

OPG correlated significantly with age (Spearman’s rho (r) = 0.359, p < 0.001), cystatin C (r = 0.298, p < 0.001), E2 (r = 0.160, p = 0.028) and free testosterone index (FTI) (r = −0.230, p = 0.001). Compared to the middle-aged (age: ≤ 59 years, n = 98), older men (age > 59 years, n = 96) had significantly higher serum OPG (4.6 pmol/L vs. 5.4 pmol/L; p < 0.001), and lower sRANKL (0.226 pmol/L vs. 0.167 pmol/L; p = 0.048) levels. The older men showed a significant correlation between serum OPG levels and cystatin C (Spearman’s rho = 0.322, p = 0.002), and E2 (Spearman’s rho = 0.211, p = 0.043). Including cystatin C and E2 in a regression model showed that cystatin C (standard regression coefficient (β) = 0.345; p = 0.002) was the only significant predictor of serum OPG levels in the older men.

Conclusions

The results of this study demonstrated that in addition to age (which was the stronger predictor), other modifiable factors such as cystatin C, FTI and E2 were also significant predictors of OPG, and that the association between cystatin C and OPG was more evident with increased age (older age group). As such, cystatin C is a significant predictor of OPG independently of age, FTI and E2.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-015-0684-1) contains supplementary material, which is available to authorized users.

Serum Cystatin C, Markers of Chronic Kidney Disease, and Retinopathy in Persons with Diabetes

PURPOSE

We examined the association of CKD defined by serum creatinine, serum cystatin C, and albuminuria with moderate diabetic retinopathy (DR).

METHODS

We examined 1,119 Indian adults with diabetes, aged 40-80 years, who participated in the Singapore Indian Eye Study (2007-2009), a population-based cross-sectional study. The associations of CKD defined by each of the three markers alone and in combination with moderate DR were examined using logistic regression models adjusted for potential confounding factors including duration of diabetes, smoking, body mass index, systolic blood pressure, and HbA1c.

RESULTS

The prevalence of moderate DR was significantly higher among those with CKD defined by triple markers (41.1%) compared to CKD defined separately by creatinine (26.6%), cystatin C (20.9%), and albuminuria (23.4%). People with CKD defined by triple markers had a fourteenfold higher odds of moderate DR (OR (95% CI) = 13.63 (6.08-30.54)) compared to those without CKD by any marker. Nearly half (48.7%) of participants with cystatin C ≥ 1.12 mg/L have moderate DR.

CONCLUSIONS

CKD defined by a triple marker panel was strongly associated with moderate DR in this Asian population with diabetes.

The association between body composition and cystatin C in South Asians: results from the MASALA study

While South Asians have high rates of obesity and kidney disease, little is known about the effect of regional body composition on kidney function. We investigated the association between body composition measures and cystatin C-based estimated glomerular filtration rate (eGFRcysC) in 150 immigrant South Asians. The inverse association between overall adiposity and eGFRcysC was attenuated by C-reactive protein (CRP), while the association of ectopic fat was completely attenuated by metabolic covariates and CRP. In immigrant South Asians, the associations between overall adiposity and ectopic fat with decreased kidney function are largely explained by metabolic alterations and inflammation.