Plasma total bilirubin levels predict amputation events in type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study.
ABSTRACT AIMS/HYPOTHESIS: Bilirubin has antioxidant and anti-inflammatory activities. Previous studies demonstrated that higher bilirubin levels were associated with reduced prevalence of peripheral arterial disease (PAD). However, the relationship between bilirubin and lower-limb amputation, a consequence of PAD, is currently unknown. We hypothesised that, in patients with type 2 diabetes, bilirubin concentrations may inversely associate with lower-limb amputation. METHODS: The relationship between baseline plasma total bilirubin levels and amputation events was analysed in 9,795 type 2 diabetic patients from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study. The analysis plan was pre-specified. Lower-limb amputation was adjudicated blinded to treatment allocation. Relevant clinical and biochemical data were available for analyses. Amputation was a pre-specified tertiary endpoint. RESULTS: Bilirubin concentrations were significantly inversely associated with lower-limb amputation, with a greater than threefold risk gradient across levels. Individuals with lower bilirubin concentrations had a higher risk for first amputation (HR 1.38 per 5 μmol/l decrease in bilirubin concentration, 95% CI 1.07, 1.79, p = 0.013). The same association persisted after adjustment for baseline variables, including age, height, smoking status, γ-glutamyltransferase level, HbA(1c), trial treatment allocation (placebo vs fenofibrate), as well as previous PAD, non-PAD cardiovascular disease, amputation or diabetic skin ulcer, neuropathy, nephropathy and diabetic retinopathy (HR 1.38 per 5 μmol/l decrease in bilirubin concentration, 95% CI 1.05, 1.81, p = 0.019). CONCLUSIONS/INTERPRETATION: Our results identify a significant inverse relationship between bilirubin levels and total lower-limb amputation, driven by major amputation. Our data raise the hypothesis that bilirubin may protect against amputation in type 2 diabetes.
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ABSTRACT: Background: Considerable evidence suggests that bilirubin is a potent physiologic antioxidant that may provide important protection against cardiovascular disease (CVD) and inflammation. We investigated the relationship between serum total bilirubin (TB) levels and arterial stiffness, measured by the brachial-ankle pulse wave velocity (baPWV), in patients with type 2 diabetes. Methods: We conducted a cross-sectional analysis of 1,711 subjects with type 2 diabetes (807 men and 904 women; mean age, 57.1 years). The subjects were stratified based on gender-specific tertiles of TB values, and a high baPWV was defined as greater than 1,745 cm/s (>75th percentile). Results: The serum TB concentration was negatively correlated with the duration of diabetes, HbA1c, the 10-year Framingham risk score, and baPWV and was positively correlated with high-density lipoprotein cholesterol and the eGFR in both genders. Inverse association between TB categories and unadjusted prevalence of high PWV was only observed in women. After adjusting for confounding factors, the TB levels were inversely associated with a greater risk of a high baPWV, both as a continuous variable [a 1-SD difference; odds ratio (OR), 0.70; 95% confidence interval (CI), 0.54-0.90; P = 0.005] and when categorized in tertiles (the highest vs. the lowest tertile; OR, 0.49; 95% CI, 0.28-0.85; P = 0.011) in women but not in men. The relationship remained significant even after adjusting for retinopathy and nephropathy. Conclusions: Low TB levels were significantly associated with arterial stiffness in Korean women with type 2 diabetes. Our data suggested that bilirubin may protect against macrovascular disease in diabetic women.PLoS ONE 10/2014; 9(10):e109251. DOI:10.1371/journal.pone.0109251 · 3.53 Impact Factor
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ABSTRACT: Objective: Bilirubin may protect against atherosclerotic cardiovascular disease (CVD). The heme oxygenase pathway is crucial for bilirubin generation, and is stimulated by adiponectin. We tested the relationship of plasma bilirubin with adiponectin, and determined whether the association of incident CVD with bilirubin is modified by adiponectin. Methods: A community-based prospective nested case control study (PREVEND cohort) was carried out in 87 non-diabetic men who developed a first cardiovascular event (cases) and 94 controls during a median follow-up of 6.1 (2.8-10.6) years. Results: In all subjects combined, bilirubin was positively related to adiponectin (r = 0.205, P = 0.006). Age-adjusted incident CVD was inversely associated with bilirubin (hazard ratio (HR): 0.80 (95% CI 0.65-0.99), P=0.048), independently of adiponectin (HR: 0.78 (95% CI 0.63-0.97), P=0.027). Adiponectin did not modify the association of CVD with bilirubin (interaction term: P=0.65). After additional adjustment for CVD risk factors, neither the association of incident CVD with bilirubin nor with adiponectin remained significant (P>0.20 for both), and there was again no interaction between bilirubin and adiponectin on CVD risk (P=0.67). Conclusion: Bilirubin is related to adiponectin, but the association of bilirubin with CVD risk is largely unaffected by adiponectin.Atherosclerosis 06/2014; 235(2):380-383. DOI:10.1016/j.atherosclerosis.2014.05.938 · 3.71 Impact Factor
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ABSTRACT: We evaluated the potential cardiovascular risk protection of bilirubin in hemodialysis (HD) patients. An enlarged set of studies were evaluated in 191 HD patients, including hematological study, lipid profile, iron metabolism, nutritional, inflammatory markers, and dialysis adequacy. The TA duplication screening in the UDP-glucuronosyltransferase 1 A1 (UGT1A1) promoter region was also performed. The UGT1A1 genotype frequencies in HD patients were 49.2%, 42.4%, and 8.4% for 6/6, 6/7, and 7/7 genotypes, respectively. Although no difference was found in UGT1A1 genotype distribution between the three tertiles of bilirubin, significant differences were found with increasing bilirubin levels, namely, a decrease in platelet, leukocyte, and lymphocyte counts, transferrin, oxidized low-density lipoprotein (ox-LDL), ox-LDL/low-density lipoprotein cholesterol ratio, apolipoprotein (Apo) A, Apo B, and interleukin-6 serum levels and a significant increased concentration of hemoglobin, hematocrit, erythrocyte count, iron, transferrin saturation, Apo A/Apo B ratio, adiponectin, and paraoxonase 1 serum levels. After adjustment for age these results remained significant. Our data suggest that higher bilirubin levels are associated with beneficial effects in HD patients, by improving lipid profile and reducing the inflammatory grade, which might contribute to increase in iron availability. These results suggest a potential cardiovascular risk protection of bilirubin in HD patients.BioMed Research International 09/2014; 2014:175286. DOI:10.1155/2014/175286 · 2.71 Impact FactorThis article is viewable in ResearchGate's enriched formatRG Format enables you to read in context with side-by-side figures, citations, and feedback from experts in your field.