The impact of serum bilirubin on diabetic nephropathy and pulmonary function in type II diabetic patients

Introduction: Diabetes mellitus may be associated with many complications including diabetic nephropathy and pulmonary impairment, the pathogenesis and progression of these complications may be related to oxidative stress. Bilirubin, which is a non-polar molecule have antioxidant properties. The relationship between occurrence, development and prognosis of diabetic complications and bilirubin concentration had become a research focus. However, no study has evaluated the relationship between protective effect of bilirubin on both diabetic nephropathy and pulmonary impairment in type II diabetic patients. Methods: The design of the study is a cross sectional study included 245 type II diabetic patients. Spirometry was done for all patients. Albumin/creatinine ratio (ACR), glycosylated hemoglobin, total serum bilirubin and serum glutathione reductase enzyme were measured. Results: There was a significant statistical negative relationship between serum bilirubin and glutathione reductase enzyme with ACR and significant statistical positive relationship between serum bilirubin and glutathione reductase enzyme with lung function parameters (forced expiratory volume in the first second and forced vital capacity). Conclusion: serum bilirubin levels had a protective effect against diabetic nephropathy and impairment of pulmonary function. If serum bilirubin levels were moderately high but within the normal range, this was related with decreased risk of diabetic complications and there was a parallel relationship between serum bilirubin levels and the glutathione reductase enzyme levels in type II diabetic patients.