The Epidemiology of Bile Acid Diarrhea in Denmark [Response to Letter]

Dear editor

We read the Letter to the Editor by Nurmayanti et al regarding our recent study investigating the epidemiology of bile acid diarrhea (BAD) in Denmark¹ with interest.

Nurmayanti et al appreciate the importance of our study and the robust design, which we are thankful for. They, then, state that the study “may not reflect the true prevalence of BAD in the Danish population”, which we agree with. As we state in the discussion, our priority was to define and include individuals that we were confident suffered from BAD thereby excluding individuals not diagnosed by ⁷⁵selenium homotaurocholic acid (SeHCAT) test and/or individuals who never redeemed a prescription of bile acid sequestrants. Importantly, our study was not designed to establish the true prevalence of BAD in the Danish population, but to describe the demographic characteristics of individuals suffering from BAD in Denmark.

Next, Nurmayanti et al find that the regional differences in the number of BAD diagnoses are not adequately explained. The reason(s) for these differences is difficult to investigate; however, since Denmark is a small country with low regional variation within demographic characteristics, healthcare utilization, and medication use,² we speculate that these differences are more likely to be explained by differences in clinical practice and traditions rather than differences in the population, as also mentioned in our discussion.¹

Nurmayanti et al suggest that further research is needed to understand the causal relationship between BAD and low income and education levels. We agree that studying this question would be interesting, but it was not in the scope of this study, and has previously been addressed by others, as referenced in our discussion.^3,4

Nurmayanti et al highlight the need for further information on the safety and efficacy of using liraglutide to treat BAD. We agree that this is warranted, but we do not find register-based research suitable to address this question. The safety and efficacy of liraglutide have been investigated in a six-week randomized, double-blind, double-dummy clinical trial,⁵ addressed in a registry-based analysis of prescription patterns,⁶ and described in case reports.^7–9

Lastly, Nurmayanti et al suggest that our study could have been improved with surveys and interviews to include individuals who had not undergone a SeHCAT test or were not using bile acid sequestrants and to analyze regional differences. We agree that these aspects would be interesting to address in future studies.