Raised leptin concentrations among South Asian patients with chronic heart failure.
BACKGROUND: The disease presentation of chronic heart failure (CHF) is considered to progress with metabolic deterioration, underlined by changes in adipose associated hormones (adipocytokines). However, little is known about ethnic variations of adipocytokines amongst CHF patients, in particular South Asians, who are at an increased risk of CHF. METHODS: Using a cross-sectional study, South Asians (n=106) and Caucasians (n=105) living in the UK were compared by CHF status. We investigated ethnic differences in adipocytokines (leptin, adiponectin, tumor necrosis factor (TNF)alpha), and their association with CHF. Patients with mild to moderate CHF were recruited from heart failure clinics (47 Caucasian, 54 South Asian), and compared to healthy controls. Metabolic parameters (including insulin resistance using HOMA modelling), echocardiography and brain natriuretic peptide (BNP) were measured amongst patients and healthy controls, and compared across and within ethnic groups. RESULTS: Mean (log transformed) plasma leptin concentrations were highest amongst South Asian patients, being 5.25% (95%CI: 1.50-9.02) higher than Caucasian patients (P=0.007), and similarly raised with respect to controls (P< or =0.04). Indices of insulin resistance were higher amongst CHF patients compared with controls, with no ethnic variation. In addition to age, female gender and body-mass index, levels of leptin were also associated with South Asian ethnicity (P<0.001), insulin resistance (P=0.02), smoking habit (P=0.01) and HDL cholesterol (P=0.004). Levels of adiponectin showed no ethnic variation, but were associated with CHF and a previous history of myocardial infarction (P<0.001). On multivariate regression analysis of patients and healthy controls, CHF was independently associated with smoking habit, adiponectin and insulin resistance (all P<0.01). CONCLUSION: Metabolic abnormalities are present in CHF, which in turn, are influenced by ethnicity. The role of adipocytokines in CHF pathophysiology and prognosis merits further study.