Reduced bile acid excretion is an independent risk factor for stroke and mortality: A prospective follow-up study

Background and aims: Hypercholesterolemia is a major risk factor for atherosclerosis, which is a cornerstone of coronary artery disease (CAD), stroke, peripheral vascular disease, aortic aneurysm and renal artery stenosis. This study investigated the association of bile acid excretion (BAE) with stroke incidence and mortality.

Methods: Patients admitted to Internal Medicine due to chest pain and suspected CAD were enrolled and followed from 1/1998 to 12/2018. Patients received a standard in-hospital diet containing 490 mg/day cholesterol and performed a 24-h stool collection. A continuous, non-absorbable marker was used to evaluate the amount of BAE.

Results: This retrospective, historical, follow-up study included 68 men and 35 women (mean age 61.9 ± 8.9 years) admitted to the hospital from 1996 to 1998 due to chest pain and suspected cardiac event. Mean BAE at first admission was higher among survivors (>608.8 mg) than non-survivors (281.5 mg/24h; p<0.001). Total cholesterol, LDL cholesterol and triglyceride levels at baseline did not differ significantly. The main fractions of deoxycholic, lithocholic, and cholic acids were significantly different in the two groups. They were also higher in the survivors. Total BAE was higher in stroke-free patients compared to those who developed stroke: 561.6 mg/24h and 231.2 mg/24h-respectively (p<0.001). Patients with BAE <262.4 developed stroke in 75% cases (18/24). None of 25 patients with BAE >622 mg/24h developed stroke.

Conclusion: This retrospective, historical cohort follow-up study showed an association between lower amounts of total bile acid, deoxycholic acid and lithocholic acid excretion with stroke risk. Low BAE remained a significant risk-factor after adjusting for main potential confounders and may be an independent risk-factor for stroke.