Low serum bilirubin concentration in haemodialysis patients with Type 2 diabetes

Previous studies have implicated reduced serum bilirubin concentrations in the development of cardiovascular disease. The aim of this study was to examine whether bilirubin may explain the high incidence of vascular complications in haemodialysis patients with Type 2 diabetes.

We compared serum bilirubin concentrations, as well as other known aetiological risk factors for cardiovascular disease, in 206 Type 2 diabetes patients on haemodialysis with those in 741 Type 2 diabetes patients not receiving haemodialysis, and evaluated the association between serum bilirubin concentration and cardiovascular disease incidence.

Incidences of cardiovascular disease and systolic blood pressure were higher; however, BMI and serum total cholesterol were lower in haemodialysis patients compared with those in patients without haemodialysis. Serum total (0.30 ± 0.10 vs. 0.74 ± 0.26 mg/dl, 0.005 ± 0.002 vs. 0.013 ± 0.004 mmol/l, P < 0.0001) and indirect (0.17 ± 0.08 vs. 0.70 ± 0.23 mg/dl, 0.003 ± 0.001 vs. 0.012 ± 0.004 mmol/l, P < 0.0001) bilirubin were lower in haemodialysis patients compared with those in patients without haemodialysis. Stepwise regression analysis demonstrated that age (β = 0.109, F = 5.959, P < 0.05), duration of diabetes (β = -0.112, F = 6.048, P < 0.05), sex (β = -0.123, F = 8.623, P < 0.05), cardiovascular disease events (β = -0.099, F = 5.131, P < 0.05) and presence of haemodialysis (β = -0.626, F = 201.727, P < 0.01) were independent factors for serum total bilirubin. Logistic regression demonstrated that age (OR 1.089, 95% CI 1.044-1.136; P < 0.0001), duration of diabetes (OR 1.029, 95% CI 1.001-1.059; P = 0.0423), body mass index (OR 1.115, 95% CI 1.001-1.242; P = 0.0487), habit of smoking (OR 2.445, 95% CI 1.046-5.716; P = 0.0391) and serum total bilirubin (OR 0.192, 95% CI 0.037-0.989; P = 0.0484) were independent factors for cardiovascular disease events.

Low serum bilirubin concentration could be one of the important factors for the high incidence of cardiovascular disease in Type 2 diabetes patients receiving haemodialysis.