Gilbert syndrome in patients with type 1 diabetes-Prevalence, glycemic control, and microalbuminuria

Gilbert syndrome (GS) is a common hereditary condition, characterized by intermittent unconjugated hyperbilirubinemia. In adults with type 2 diabetes and GS, a markedly lower prevalence of nephropathy was documented, suggesting a beneficial effect of hyperbilirubinemia. We investigated the prevalence of GS among individuals with type 1 diabetes mellitus (T1DM), and the prevalence of microalbuminuria.

The prevalence of GS was assessed in 401 (204 female) patients with T1DM, median age 21.0 years, (interquartile range [IQR], 15.7-27.9), median disease duration 10.8 years (IQR, 5.7-15.8); and was compared with GS prevalence in 181 children (control). The prevalence of microalbuminuria was assessed in patients with T1DM and GS (group I) and compared with that of patients with T1DM alone (group II), in a ratio of 1:2 matched by gender, age, and duration of diabetes.

The prevalence of GS in TIDM patients was significantly higher than in the control group (10.7% vs 3.3% respectively, p = .004), with no gender difference. Patients with T1DM and GS had significantly lower HbA1c levels than did those with T1DM alone 7.3 ± 1.2 vs 7.9 ± 1.3% respectively (56 ± 13 vs 63 ± 14 mmol/mol), p = .02. The rate of microalbuminuria was 14.0% vs 11.0% for patients with T1DM and GS, compared with those with T1DM alone (p = .6).

The occurrence of GS was 3-fold higher among individuals with T1DM than in a healthy control group. Despite better glycemic control, the rate of microalbuminuria was similar among young individuals with T1DM and GS, and those with T1DM alone, suggesting no protective value to elevated bilirubin.