Platelet mean volume, distribution width, and count in type 2 diabetes, impaired fasting glucose, and metabolic syndrome: a meta-analysis.

Abstract

Platelet activation contributes to cardiovascular disease (CVD), the main complication of type 2 diabetes mellitus (T2DM) and pre-diabetic conditions. Mean platelet volume is an easy-to-measure platelet parameter that has been associated with CVD. We sought to assess mean platelet volume, platelet distribution width, and platelet count in T2DM, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and metabolic syndrome. Web-based literature search (PubMed, EMBASE, and Web of Science) of studies published in English through June 2014 was performed to select case-control and cross-sectional studies that reported data on mean platelet volume, platelet distribution width, or platelet count in cases (subjects with T2DM, IFG, IGT, or metabolic syndrome) and noncases. Descriptive and quantitative information was extracted, and within-study standardized mean difference was estimated from means and standard deviations. Standardized mean differences across studies were synthesized using a random random-effects model, and subgroup analyses were performed on pre-specified study-level characteristics. Thirty-nine studies were included. Compared with controls, mean platelet volume was significantly higher in T2DM (standardized mean difference, 95% confidence interval: 0.70, 0.50-0.91; N = 24,245), IFG (0.14, 0.02-0.26; N = 17,389) but not in metabolic syndrome (0.15, -0.24 to 0.55; N = 14,990). Platelet distribution width was wider in T2DM (0.93, 0.09-1.76; N = 471). Platelet count resulted higher in IFG (0.18, 0.12-0.24; N = 3960) and metabolic syndrome (0.39, 0.01-0.78; N = 4070). Only two studies included IGT. Available data suggest that T2DM subjects tend to have higher mean platelet volume and platelet distribution width values, but nondifferent platelet count as compared with subjects without T2DM. Whether and how these morphometric changes contribute to CVD of T2DM or can be used as CVD biomarker awaits further investigation.