Search

Abstract Background Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT). Methods We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm. Results Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate. Conclusions Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.

Patients with classic symptoms of celiac disease are often initially tested for serum tissue transglutaminase-immunoglobulin A (tTG-IgA) and total serum immunoglobulin A (IgA) levels concurrently, as IgA deficiency can lead to falsely low tTG-IgA. There are no guidelines for incidental findings of elevated total serum IgA when testing for celiac disease. In our study, we described the proportion of patients with suspicion of celiac disease who had elevated total serum IgA and the factors that may be associated with these findings. We studied the management of these patients with incidental findings of elevated total serum IgA to identify its clinical significance. To investigate, we performed a retrospective chart review of patients who underwent celiac disease serologic testing at a single clinic from January 2017 to June 2022. We reported further laboratory workup and follow-up for patients with incidental findings of elevated total serum IgA by board-certified immunologists. In our chart review, 848 patients were identified, 85 (10.0%) of whom were found to be negative for celiac disease but had elevated total serum IgA levels (median IgA 351 mg/dL, interquartile range 324–382). Out of 85 patients, 73 were further evaluated by immunologists, with 55 patients undergoing additional laboratory workup. None were diagnosed with specific immunologic conditions. Male sex was identified as associated with elevated total serum IgA findings, and constipation was found in a statistically significant greater frequency of patients with normal total serum IgA rather than elevated total serum IgA. To provide external validation of our findings, we created a second patient cohort within the Stanford Research Repository database. Out of 33,875 patients identified, a similarly high proportion of patients were negative for celiac disease but had elevated total serum IgA levels (9.3%, 3140 patients). In this separate patient cohort, male sex was also identified as being associated with elevated total serum IgA. Our study also provides preliminary evidence that patients with incidental findings of elevated total serum IgA may not need further management or workup, as these abnormalities may not be clinically relevant without other clinical suspicions.