Insulin Resistance is the Major Determinant for Microalbuminuria in Severe Hypertriglyceridemia: Implication for High-Risk Stratification

OBJECTIVE: The significance of high triglyceride levels as a risk factor for coronary heart disease is uncertain. We hypothesized that oral glucose tolerance test (OGTT) and certain novel markers may help to identify high-risk patients. PATIENTS AND METHODS: We recruited 80 subjects with severe hypertriglyceridemia (age 27-73 years) without clinical proteinuria and diabetes mellitus (DM) which were diagnosed by fasting glucose <126 mg/dL from Hyperlipidemia Clinic of National Taiwan University Hospital for this study. We applied OGTT to evaluate occult DM and homeostasis model assessment (HOMA)-insulin resistance (IR) score to evaluate insulin resistance, and the measurements of microalbuminuria as a marker of vascular damage. In addition, serum or plasma markers of inflammation and fibrinolysis, fasting glucose and insulin as well as traditional cardiovascular risk factors were also evaluated. RESULTS: The serum level of triglyceride was higher in patients with microalbuminuria than in those without (14.1+/-5.7 vs. 9.6+/-3.9 mmol/L, p=0.025). Patients with microalbuminuria had higher fasting blood glucose and insulin, higher post-OGTT glucose and insulin, higher prevalence of newly developed diabetes mellitus (DM) (39% vs. 11%, p=0.007) and higher HOMA-IR (6.2+/-4.4 vs. 3.3+/-2.0, p<0.001). Among all the inflammatory and fibrinolytic markers, only soluble intercellular adhesion molecule showed significant different between these two groups. Multiple logistic regression analysis showed that among the serum markers, only HOMA-IR level was significantly related to microalbuminuria. CONCLUSIONS: HOMA-IR is the major determinant for microalbuminuria in patients with severe hypertriglyceridemia. Impaired glucose metabolism is evident in patients with both severe hypertriglyceridemia and microalbuminuria.