Sucrase Isomaltese Deficiency Prevalent in Patients with IBS-D

May 23, 2021
Connor Iapoce

Connor Iapoce is an assistant editor for HCPLive and joined the MJH Life Sciences team in April 2021. He graduated from The College of New Jersey with a degree in Journalism and Professional Writing. He enjoys listening to records, going to concerts, and playing with his cat Squish. You can reach him at

Data show nearly 1 in 10 patients with IBS-D in study were identified with SID.

A new study aimed to determine the prevalence of sucrase isomaltase deficiency in adults with Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D) or function diarrhea, as there is limited data on SID in symptomatic adults.

Investigators, led by Samuel Chey, MPH, Division of Gastroenterology, Department of Internal Medicine, Michigan Medicine, identified SID in nearly 1 in 10 patients with IBS-D or function diarrhea.

The study was presented virtually at the 2021 Digestive Disease Week (DDW) Virtual Meeting.


The ongoing study recruited adult patients ≥18 years, who fulfilled Rome IV criteria for IBS-D or functional diarrhea and scheduled to undergo esophagogastroduodenoscopy.

Investigators excluded patients from the study due to pregnancy, other IBS subtypes, severe GI comorbidities, or a history of previous GI surgeries.

Eligible patients in the study completed the IBS symptom severity scale (IBS-SSS), undergoing upper endoscopy with small intestinal biopsies which were collected from the duodenum distal to the ampulla.

Then, the biopsy specimens went through disaccharidase assay (DA) for SI activity (normal sucrase: ≥28.0 µM/min/g, normal maltase: ≥120.8 µM/min/g).


A total of 58 patients were enrolled in the study, with a mean age of 42.6 years, 74% female and 93% white.

Of the patient population, 67% had IBS-D and 33% had functional diarrhea. The mean IBS-SSS was 232±17, including moderately severe abdominal pain and bloating scores.

Investigators noted that all patients in the study were not happy with bowel habits and felt the symptoms were a frequent interference.

Out of 58 patients, 5 tested positive for SID through DA, with a mean IBS-SSS score of 218±4, suffering from moderately severe abdominal pain and bloating scores.

The 5 patients positive for SID were equally unhappy with bowel habits, but felt their symptoms had a greater interference with their daily lives compared to the total study population.

The team found 4 of 5 SID patients reported lifelong issues with GI distress, such as abdominal discomfort and loose stool, while 4 of 5 patients reported onset of diarrhea symptoms within 10 years of participation in the study.

All 5 SID patients underwent treatment, ranging from low-FODMAP diet to anti-diarrheal medication.

Investigators noted that 2 of 5 SID patients were found to have carcinoid tumors following study participation.


Investigators concluded that SID patients tend to have lifelong symptoms that significantly interfere with their daily lives.

“These results require validation in a larger patient sample but suggest SID may be an important and overlooked cause for symptoms in US patients diagnosed with IBS-D or functional diarrhea,” investigators wrote.

The study, “Prevalance of Sucrase-Isomaltese Deficiency in Adults with Irritable Bowel Syndrome and Diarrhea and Functional Diarrhea: An Interim Analysis from a Prospective US Trial,” was published online by DDW.