[Analysis of metabolic syndrome and pulse wave velocity in hemodialysis patients: diagnosis of obesity by bioelectrical impedance analysis and a novel risk factor for atherosclerosis]

Abstract

Purpose: Metabolic syndrome (Met S) is one of the risk factors of atherosclerotic vascular diseases related to visceral fat accumulation. However, it is well known that morbidity and mortality of hemodialysis (HD) patients are associated with malnutrition and emaciation rather than obesity, representing "reverse epidemiology". The risk of visceral fat accumulation or Met S in HD patients remains unclear. Therefore, we evaluated atherosclerosis and Met S in HD patients using various markers of obesity by means of bioelectrical impedance analysis (BIA) and brachial-ankle PWV(baPWV).

Methods: The subjects comprised 52 patients who were undergoing maintenance dialysis. In addition to a general physical examination and routine blood tests, immunoreactive insulin (IRI), homeostasis model assessment for insulin resistance (HOMA-R), serum adiponectin (ADPN) and C-reactive protein (CRP)were measured before dialysis. Furthermore, we measured various body fluid components, such as the ratio of extracellular water to total body water (ECW/TBW), body fat mass (BFM), percent body fat(PBF) and visceral fat accumulation (BIA-VFA), using a body composition analyzer (InBody S20)and baPWV as a marker of atherosclerosis.

Results: There was no significant difference between HD patients with and without Met S for baPWV. baPWV was positively correlated with age, systolic BP and ECW/TBW, and negatively correlated with serum albumin level, BMI and serum ADPN. However, no significant correlations were observed between baPWV and the durations of HD, Ca x P product, BIA-VFA, PBF, HOMA-R and CRP. The serum ADPN level was significantly lower in Met S than in non-Met S. In addition, the ADPN level was positively correlated with HDL-cholesterol, and negatively correlated with TG, HbA1c, CRP and various markers of obesity (Waist, BIA-VFA, BFM and PBF). In a multiple regression analysis for baPWV, the ECW/TBW ratio and serum ADPN level, as well as age and systolic BP, were independent predictors for the enhancement of baPWV in HD patients.

Conclusion: The present study demonstrated that the ECW/TBW ratio and low serum ADPN level, but not Met S or obesity, could be risk factors for the acceleration of atherosclerosis in HD patients. In addition, the results showed that the relationship between ADPN,as an anti-atherosclerotic factor, and body fat or lipid metabolism were also maintained in HD patients.