G ilbert's syndrome and the risk of death: A population‐based cohort study

Background and Aims G ilbert's syndrome is a common familial hyperbilirubinemia that may reduce the risk of various age‐related diseases because of the antioxidant properties of bilirubin. We conducted a large cohort study using T he H ealth I mprovement N etwork primary care database and compared all‐cause mortality rates in those with and without G ilbert's syndrome. Methods Mortality rates in patients with a diagnosis of G ilbert's syndrome and raised bilirubin level ( n  = 4266) were compared with those of patients with similar characteristics but with normal bilirubin levels ( n  = 21 968). Multivariate Poisson regression was also used to estimate adjusted mortality rate ratios. Results During the 350 000 PY s of follow up across the G ilbert's and comparison cohorts, there were 1174 deaths. Mortality rates were 24/10 000 PY s in the G ilbert's cohort versus 50/10 000 PY s in the comparison cohort. Mortality rates were around half in patients with G ilbert's syndrome after accounting for sociodemographics and general health indicators (adjusted mortality rate ratio: 0.5 [95% confidence interval; 0.4–0.7; P  < 0.001]). Conclusions Mortality rates observed for people with G ilbert's syndrome in the general population are almost half those of people without evidence of G ilbert's syndrome.