Use of serum cystatin C to detect early decline of glomerular filtration rate in type 2 diabetes

Serum cystatin C as an early marker of nephropathy among type 2 diabetics: A meta-analysis

AIM

The varying views as to the usefulness of serum cystatin C (CysC) as an early marker of diabetic nephropathy (DN) prompted us to investigate existing literature to determine whether serum CysC can be used as an early marker of DN using a meta-analysis approach.

MATERIALS AND METHODS

Twelve studies written in English were retrieved from PubMed using various key search terms. Data were extracted from the included studies by two of the authors and was subjected to statistical analysis using Review Manager 5.3 and Meta-Essentials. Levels of serum CysC were compared between the study groups using the standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

Overall outcomes indicate that serum CysC levels are higher among those with microalbuminuria (MI) and macroalbuminuria (MA) than those in the control group (CN) and those with normoalbuminuria (NO). However, these findings were heterogeneous, which warranted an investigation using the Galbraith plot. Heterogeneity was either reduced or lost in the post-outlier outcomes indicating combinability of the studies.

CONCLUSION

Serum CysC is shown to be a superior biomarker in the early diagnosis of DN. However, further studies are still needed to verify our claims.

Effects of a Multicomponent Life-Style Intervention on Weight, Glycemic Control, Depressive Symptoms, and Renal Function in Low-Income, Minority Patients With Type 2 Diabetes: Results of the Community Approach to Lifestyle Modification for Diabetes Randomized Controlled Trial

OBJECTIVE

Few interventions have combined life-style and psychosocial approaches in the context of Type 2 diabetes management. The purpose of this study was to determine the effect of a multicomponent behavioral intervention on weight, glycemic control, renal function, and depressive symptoms in a sample of overweight/obese adults with Type 2 diabetes and marked depressive symptoms.

METHODS

A sample of 111 adults with Type 2 diabetes were randomly assigned to a 1-year intervention (n = 57) or usual care (n = 54) in a parallel groups design. Primary outcomes included weight, glycosylated hemoglobin, and Beck Depression Inventory II score. Estimated glomerular filtration rate served as a secondary outcome. All measures were assessed at baseline and 6 and 12 months after randomization by assessors blind to randomization. Latent growth modeling was used to examine intervention effects on each outcome.

RESULTS

The intervention resulted in decreased weight (mean [M] = 0.322 kg, standard error [SE] = 0.124 kg, p = .010) and glycosylated hemoglobin (M = 0.066%, SE = 0.028%, p = .017), and Beck Depression Inventory II scores (M = 1.009, SE = 0.226, p < .001), and improved estimated glomerular filtration rate (M = 0.742 ml·min·1.73 m, SE = 0.318 ml·min·1.73 m, p = .020) each month during the first 6 months relative to usual care.

CONCLUSIONS

Multicomponent behavioral interventions targeting weight loss and depressive symptoms as well as diet and physical activity are efficacious in the management of Type 2 diabetes.

TRIAL REGISTRATION

This study is registered at Clinicaltrials.gov ID: NCT01739205.

Is serum cystatin C an accurate endogenous marker of glomerular filteration rate for detection of early renal impairment in patients with type 2 diabetes mellitus?

BACKGROUND

Researches have recently reported that serum cystatin C is a more sensitive marker of changes in glomerular filtration rate (GFR) than serum creatinine. We conducted this study to evaluate the significance of serum cystatin C as a more sensitive marker of GFR for early detection of renal impairment in special groups of patients with type 2 diabetes mellitus (DM).

METHODS

The present study included 40 patients with type 2 DM divided into four equal groups based on their urinary albumin excretion and renal function: group 1 was normoalbuminuric, group 2 was microalbuminuric, group 3 was macroalbuminuric, and group 4 was macroalbuminuric with renal dysfunction. All patients underwent a thorough history, full clinical examination, fasting, and renal function tests. Post-prandial blood glucose levels, glycosylated hemoglobin A1c (HbA1c), proteins, albumin in 24 hr urine, and serum cystatin C were collected.

RESULTS

Serum cystatin C and creatinine were significantly higher in macrolbuminuric type 2 diabetic patients with renal dysfunction (group 4: 2.26 +/- 1.28, 4.21 +/- 2.38 mg/dl, respectively; p < 0.001) than macrolbuminuric type 2 diabetic patients with normal renal function (group 3: 1.04 +/- 0.24, 0.96 +/- 0.20 mg/dl, respectively), the microalbuminuric group (0.87 +/- 0.28, 0.71 +/- 0.12 mg/dl, respectively), as well as the normoalbuminuric group (0.55 +/- 0.41, 0.60 +/- 0.18 mg/dl, respectively). ROC plots demonstrated that area under the curve (AUC) of cystatin C (0.74) was greater than that for creatinine clearance (cr.cl) (0.67) and serum creatinine (s-cr) (0.74); therefore, the sensitivity and diagnostic accuracy of cystatin c was better than cr. cl., and both were better than s-cr. Serum cystatin C showed significant correlation in groups 2-4 with s-cr, cr.cl, and 24 hr urine albumin, but no correlation was found in group 1.

CONCLUSION

Serum cystatin C is a reliable and easily performed marker for GFR to detect renal impairment in patients with type 2 DM.

Evidence that even "normal" albuminuria may denote incipient GFR reduction in patients with type 2 diabetes mellitus

AIMS

In patients with diabetes and microalbuminuria, small changes of GFR could have been missed, due to the lack of sensitive methodology for GFR determination in clinical practice (creatinine based calculations). Therefore we explored the relation of the degree of albumin excretion with Cystatin C, which has been recently proved to be a better marker of GFR, compared to serum creatinine.

METHODS

We studied 179 patients with type 2 diabetes, in whom renal function and microalbuminuria were evaluated.

RESULTS

In patients with normal renal function, GFR/MDRD>or=60 ml/min/1.73 m(2), (n=79), urinary albumin concentration (UAC) was significantly correlated with Cystatin C, both in patients with normoalbuminuria (r=0.547, p<0.023) or microalbuminuria (r=0.305, p<0.035), while it was not correlated either with serum creatinine or calculated creatinine clearance. In patients with GFR/MDRD<60 ml/min/1.73 m(2), (n=100), UAC was significantly correlated with Cystatin C, also both in patients with normoalbuminuria (r=0.536, p<0.032) or microalbuminuria (r=0.340, p<0.016), while it was significantly correlated with serum creatinine and calculated creatinine clearance only in those with microalbuminuria.

CONCLUSIONS

Subtle changes in renal function, as judged by Cystatin C concentration, may parallel the degree of albuminuria, even in the normoalbuminuric stage. This finding needs further confirmation by more appropriate methodology in prospective follow up studies.