Mean Platelet Volume As A Marker of Increased Cardiovascular Risk in Patients With Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common cause of chronic liver disease in Western countries.1 NAFLD is frequently associated with obesity, diabetes, metabolic syndrome, and increased cardiovascular risk. Moreover, patients with the aggressive form of NAFLD, nonalcoholic steatohepatitis (NASH), may be at higher risk of atherosclerosis than patients with simple steatosis due to increased oxidative stress and systemic inflammation.2-4 Mean platelet volume (MPV) is a marker of platelet activation and a validated predictor of cardiovascular risk.5 Larger platelets are enzymatically more active than small platelets, produce more thromboxane A2, and have an increased propensity to thrombosis.6 The aim of this study was two-fold: first, to assess MPV levels in patients with biopsy-proven NAFLD, and second, to determine the relationship between the histological features of NASH and MPV. Our cohort consisted of 100 consecutive patients undergoing liver biopsy for clinical suspicion of NAFLD. Patients were divided into three groups: NASH (n = 52), simple steatosis (n = 25), and normal biopsy (n = 21). We measured MPV in blood samples collected at the time of liver biopsy. The mean age was 49.8 years (± 10.6 years), and the mean body mass index was 31.4 kg/m2 (± 4.8 kg/m2). The majority of patients were white (86%), and 48% were female. There was a stepwise significant increase in MPV levels from patients with normal biopsies to patients with simple steatosis to patients with NASH (9.5 fL, 10.2 fL, and 11.3 fL, respectively; P < 0.005) (Fig. 1). Moreover, there was a significant correlation between MPV levels and the individual histological features of NASH on liver biopsy, including inflammation (rho = 0.64), steatosis (rho = 0.65), ballooning (rho = 0.60), and fibrosis (rho = 0.61) (P < 0.001 for all). Stepwise significant increase in MPV levels from patients with normal biopsies to patients with simple steatosis to patients with NASH. The box represents the interquartile range (25th and 75th percentiles) from the median (the horizontal line), the bars represent the 95% confidence interval. We conclude that in adult patients with biopsy proven NAFLD, the histological severity of liver injury and inflammation is strongly associated with higher MPV levels and therefore potentially increased cardiovascular risk. The study has some limitations, including the cross-sectional design, small sample size, and relatively young patient population. Thus, a correlation between increasing MPV levels or NAFLD severity and previously documented cardiovascular events was not established. Larger studies are needed to validate our findings. Naim Alkhouri M.D.*, Gaurav Kistangari M.D.*, Carla Campbell R.N., SRNA*, Rocio Lopez M.D.*, Nizar N. Zein M.D.*, Ariel E. Feldstein M.S.*, * Digestive Disease Institute, Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH.