The Role of Circulating RBP4 in the Type 2 Diabetes Patients with Kidney Diseases: A Systematic Review and Meta-Analysis
Li Zhang, Yanli Cheng, Shuai Xue, Zhonggao Xu
Abstract
Background . Diabetic nephropathy is a common and serious complication of diabetes mellitus (DM) and is one of the leading causes of end-stage renal disease worldwide. Although there have been many investigations on biomarkers for DN, there is no consistent conclusion about reliable biomarkers. The purpose of this study was to perform a systematic review and meta-analysis of the role of circulating retinol-binding protein 4 (RBP4) in the type 2 diabetes mellitus (T2DM) patients with kidney diseases. Materials and Methods . We searched the PubMed, MEDLINE, EMBASE, and Web of Science databases for publications. For the 12 cross-sectional studies that we included in the review, we calculated standard mean differences (SMD) with 95% confidence intervals (CI) for continuous data when the applied scales were different. Risk of bias of included trials was assessed by using the Newcastle-Ottawa Scale. Results . RBP4 concentrations in the micro-, macro-, or micro+macroalbuminuria groups were significantly higher than those in the normal albuminuria group of T2DM patients [<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.001</mml:mn></mml:math>, SMD 1.07, 95% CI (0.41, 1.73)]. The estimated glomerular filtration rate (eGFR) was negatively associated with circulating RBP4 concentrations in patients with T2DM [summary Fisher’s<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>Z</mml:mi><mml:mo>=</mml:mo><mml:mo>−</mml:mo><mml:mn>0.48</mml:mn></mml:math>, 95% CI (-0.69, -0.26),<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>P</mml:mi><mml:mo><</mml:mo><mml:mn>0.0001</mml:mn></mml:math>]. The albumin-to-creatinine ratio (ACR) was positively associated with circulating RBP4 concentrations in patients with T2DM [summary Fisher’s<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mi>Z</mml:mi><mml:mo>=</mml:mo><mml:mn>0.20</mml:mn></mml:math>, 95% CI (0.08, 0.32),<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.001</mml:mn></mml:math>]. Conclusion . The levels of circulating RBP4 were significantly higher both in T2DM subjects with micro/macroalbuminuria and in T2DM subjects with declined eGFR. The levels of circulating RBP4 were positively correlated with ACR but negatively correlated with eGFR. Circulating RBP4 could be a reliable biomarker for kidney diseases in T2DM.