Platelet count is independently associated with insulin resistance in non-obese Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationship between platelet count and insulin resistance in non-obese Japanese type 2 diabetic patients. A total of 163 non-obese Japanese type 2 diabetic patients (112 men and 51 women, aged 36 to 84 years, body mass index [BMI] 16.2 to 26.9 kg/m 2) were studied. In conjunction with BMI, glycosylated hemoglobin (HbA 1c), fasting concentrations of plasma glucose and serum lipids (triglycerides, low-density lipoprotein [LDL] cholesterol, high-density lipoprotein [HDL] cholesterol, and total cholesterol), and hematological parameters (platelets, white blood cell count, red blood cell count, hematocrit, hemoglobin) were measured. LDL cholesterol was calculated using the Friedewald formula. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). Univariate regression analysis showed that HOMA-IR was positively correlated to BMI ( r = 0.465, P < .0001), HbA 1c ( r = 0.423, P < .0001), platelet count ( r = 0.310, P < .0001), triglycerides ( r = 0.277, P < .0005), white blood cell count ( r = .222, P = .005), red blood cell count ( r = 0.210, P = .008), hematocrit ( r = 0.156, P = .047), total cholesterol ( r = 0.178, P = .023), and systolic ( r = 0.216, P = .011) and diastolic ( r = 0.263, P = .002) blood pressure, and inversely correlated to HDL cholesterol ( r = −0.312, P < .0001) level in our diabetic patients. Multiple regression analysis showed that HOMA-IR was independently predicted by BMI ( P < .0001, F = 22.45), HbA 1c ( P < .0001, F = 16.15), platelet count ( P < .0001, F = 10.75), and serum triglycerides ( P < .0001, F = 10.47) levels, which explained 34% of the variability of HOMA-IR in non-obese Japanese type 2 diabetic patients. These results indicate that not only BMI, HbA 1c, and triglycerides levels but also platelet counts are independent predictor of insulin resistance in non-obese Japanese type 2 diabetic patients.