The Bile Acid Turnover Rate Assessed with the 75SeHCAT Test Is Stable in Chronic Diarrhoea but Slightly Decreased in Healthy Subjects After a Long Period of Time

Abstract

The stability of bile acid turnover rate was evaluated retrospectively using repeat SeHCAT tests in patients with chronic diarrhoea and prospectively for 16 years in healthy subjects. The SeHCAT values were stable in 39 patients with chronic diarrhoea, as shown by a comparison of the test results [data presented as median and (25th-75th percentile)]: 18% (8-23) in the first test versus 14% (9-21) in the second test [n = 39, P = 0.37, time interval 44 months (16-68), repeatability index >95%]. In contrast, they were reduced after 16 years in healthy subjects: 38% (30-49.5) in the first test versus 31% (21-49.5) in the second test (P < 0.03). In healthy subjects, the body mass index increased by 13% from 23.2 kg/m(2) (21-24.6) to 26.2 kg/m(2) (22.5-27.8) (P < 0.01) during the 16 years. There was a negative correlation between hepatic bile acid synthesis and the SeHCAT values (r = -0.615, P = 0.02, n = 14). In conclusion, the turnover rate of bile acids is stable over a long period of time in patients with chronic diarrhoea irrespective of bile acid malabsorption, suggesting that a repeat SeHCAT test is dispensable. There is a significant negative correlation between bile acid synthesis and SeHCAT test results in healthy subjects. The SeHCAT test values are slightly reduced in healthy subjects after 16 years.

Lenalidomide-induced diarrhea in patients with myeloma is caused by bile acid malabsorption that responds to treatment

“…75 Selenium homocholic acid taurine (SeHCAT) scanning is a noninvasive test for BAM with sensitivity of 90% to 98% and specificity of 100%. 7,8 It confirmed severe (,5% 7-day SeHCATretention) BAM in 9 patients, moderate (5% to 10%) BAM in 2 patients, and mild (10% to 15%) BAM in 1 patient. One patient had undergone SeHCAT scanning 2 years previously (43% retention) but after starting treatment with lenalidomide developed worsening diarrhea, and repeat scanning suggested lenalidomide-induced severe BAM (3% retention).…”

Increased colonic bile acid exposure: a relevant factor for symptoms and treatment in IBS

“…An alternative way of diagnosing BAM is to measure the serum concentration of 7α-hydroxy-4-cholesten-3-one (C4), which reflects the rate of the hepatic bile acid synthesis 19 30. Plasma C4 correlates inversely with 75 SeHCAT values30––32 in healthy controls and in patients with diarrhoea without morphological evidence of ileal disease 33 34. Another possible test in the diagnosis of BAM is fibroblast growth factor (FGF) 19,35 which is produced in the terminal ileum and proposed to suppress bile acid synthesis by reducing the activity of the rate-limiting enzyme cholesterol-7α-hydroxylase in the liver 36…”

The efficacy of a low-fat diet to manage the symptoms of bile acid malabsorption – outcomes in patients previously treated for cancer

“…9 Consequently, it is possible that some patients with borderline BAM/BAD may in fact have more severe malabsorption. Symptoms will also depend on the amount of fat ingested, something rarely considered by clinicians.…”

“…However, selenium-75 homocholic acid taurine (SeHCAT) scanning is available in 10 European countries, Canada and Australia (but not the USA) and has a sensitivity of 89-97% and a specificity of close to 100% for the diagnosis of BAM/BAD. 8,9 Even where the SeHCAT scan is available, usage varies widely. Clinicians in the UK request 10 times as many scans per million population compared with any other country (personal communication, General Electric).…”