Introduction

Avoidant Restrictive Food Intake Disorder (ARFID) is increasingly recognized within the paediatric population and specialist clinics. However, there is sparse data on the prevalence and burden of ARFID within the adult general population. We addressed this issue.

Aims & Methods

A population-based Internet survey with pre-defined demographic quotas was conducted across the UK and USA in 2023. The survey collected data on demographics, body mass index (BMI), ARFID (using the nine-item ARFID screening tool, NIAS), disorders of gut-brain interaction (using the Rome IV diagnostic questionnaire), PHQ-15 somatic symptoms, PHQ-4 anxiety and depression, PROMIS-10 quality of life, and healthcare utilisation.

Results

In total, 4002 adults (mean age 47 [range 18-91] years and 50% females) completed the survey. Overall, 26.0% (n=1035) screened positive for ARFID, with similar results between the UK (23.0%) and USA (29.0%). The prevalence of positive ARFID screens by NIAS subscale were 15.3% for poor appetite, 13.9% for picky eating, and 6.2% for fear of aversive consequences. In all, 18.2% had a single ARFID domain, 5.7% had two domains and 1.9% had all three domains.
ARFID was more common in females than males (29.6% vs. 22.1%, OR 1.5), and highest amongst people aged 18-39 years (31.6%), followed by those aged 40-64 years (25.0%), and lowest in those 65 years and over (16.1%); p<0.001.
Individuals with ARFID - compared to those without ARFID - had a significantly higher prevalence of disorders of gut-brain interaction (51% vs. 37.5%, OR 2.2), including irritable bowel syndrome (11.8% vs. 4.0%, OR 3.2) and functional dyspepsia (25.8% vs. 7.0%, OR 4.6). They were significantly more likely to be underweight (BMI<18.5; 7.0% vs. 1.5%), experience greater somatic symptoms and mood disturbances, reduced mental and physical quality of life, and increased healthcare utilization (i.e. medication use and doctor visits). An increase in the number of ARFID domains was associated with greater general health impairment; p<0.001.

Conclusion

Elevated ARFID symptoms are common within the adult general population, affecting 1-in-4 people, and associated with substantial health burden. Increased awareness of ARFID will aid clinical service provision and future research on how to best manage this patient group.

Disclosure

Nil

Introduction

Low mucosal impedance has been associated with reduced mucosal integrity and is measured during ambulatory pH/impedance monitoring, defined as mean nocturnal baseline impedance (MNBI)¹. More recently, techniques to measure impedance during endoscopy are emerging². In a prospective cohort of patients with EoE (SWALLeOeW Study, ISRCTN17786884, recruitment ongoing) we assessed the technicality of comparing mucosal impedance using MNBI with impedance measured during high-resolution impedance manometry (HRIM).

Aims & Methods

Here we aim to assess the practicability of obtaining mucosal impedance measurements during HRIM and to compare this with impedance measured using MNBI in a group of patients with EoE.
Prospective participants with EoE were assessed with HRIM and MNBI and this was repeated following a treatment period (Oro-dispersible Budesonide). The pooling of repeat measures from an individual participant was deemed to be appropriate in this evaluation as the purpose was to technically validate the process of comparing MNBI with HRIM, rather than to compare individual data points.
MNBI was calculated during a quiescent nocturnal period (Laborie, Ohmega) using the average of distal impedance channels 3 and 5 cm above the proximal border of the LOS¹. Impedance data was obtained during the supine resting period during HRIM and manually exported from the software (Medtronic). Extracted frames were at least 3 respiratory cycles and up to 30 seconds, and impedance was calculated based on the sensors 2.5 and 4.5, or 3.5 and 5.5 cm above the proximal border of the LOS, depending on catheter position.

Results

22 paired HRIM and MNBI measurements were obtained to date, from 15 participants. Reasons for unsuccessful MNBI measurements were not attempting test (n=2), non-tolerance (n=10), Nickel allergy (n=1), drop-out (n=2), or unable to intubate (n=1). Reasons for unsuccessful impedance measurement during HRIM were reflux during resting pressure measurement (n=1), catheter failure (n=3), drop-out (n=2), non-tolerance (n=8) or measurement not attempted (n=2).
The mean impedance values as measured by the two methods were not significantly different: mean MNBI (95% CI): 1570 (1210-1930) ohms, HRIM (95% CI) = 1330 (920-1740) ohms, p = 0.18. The mean difference between MNBI and HRIM was 245 ohms (1380-1870) (5-95^th percentiles).
Using a normality threshold of <1500 ohms³ being suggestive of impaired mucosal integrity, the majority (19/22) of the readings showed agreement between the two methods. Of the three that did not agree, MNBI suggested impaired mucosal integrity in one, and HRIM in the other two.

Conclusion

Measuring impedance during HRIM appears to be comparably practicable to MNBI measurement in patients with EoE, with the same numbers of successful measurements achieved by the two methods. Comparison of this preliminary data also indicates good agreement between methods. Impedance measurement during HRIM could provide a faster method of assessing mucosal integrity in EoE, whilst simultaneously assessing oesophageal motility. Further work in the SWALLeOeW study will correlate mucosal impedance findings with the Eosinophilic Oesophagitis Histology Scoring System⁴ and assess impedance change in response to treatment.

References

1. Hoshikawa, Y. et al. Measurement of Esophageal Nocturnal Baseline Impedance: A Simplified Method. J Neurogastroenterol Motil 26, 241–247 (2020).
2. Lei, W.-Y., Vaezi, M. F., Naik, R. D. & Chen, C.-L. Mucosal impedance testing: A new diagnostic testing in gastroesophageal reflux disease. Journal of the Formosan Medical Association 119, 1575–1580 (2020).
3. Sifrim, D. et al. Normal values and regional differences in oesophageal impedance-pH metrics: a consensus analysis of impedance-pH studies from around the world. Gut gutjnl-2020-322627 (2020).
4. Collins, M. H. et al. Newly developed and validated eosinophilic esophagitis histology scoring system and evidence that it outperforms peak eosinophil count for disease diagnosis and monitoring. Diseases of the Esophagus 30, (2016).

Introduction

The Atmo Capsule is a wireless motility capsule that senses and telemetrically transmits measurements of hydrogen (H₂) and carbon dioxide (CO₂) along the gut. In the colon, luminal concentrations of H₂ and CO₂ represent the metabolic activity of the microbial community. We hypothesized that delayed colonic transit would lead to altered gas profiles due to earlier depletion of fermentable substrates relative to transit time and/or facilitation of contact between methanogens and hydrogen (Levitt et al. CGH 2006).

Aims & Methods

The Atmo Capsule was administered to subjects with suspected upper and/or lower gut dysmotility. Colonic transit times (CTT) ≥ 59 h were considered delayed. Luminal H₂ and CO₂ concentrations (as time-normalized, area-under-the-curve [TN-AUC], [%.h]/h) were evaluated across the entire colon. Regional colonic profiles were evaluated per quartile of relative colonic transit, with quartiles 1 and 4 indicative of the proximal and distal colon, respectively. Gas measures were included if ≥ 50% of data were available for the corresponding segment. Fermentation profiles were estimated by the ratio of quartile 1:4 values, and time to peak concentrations were evaluated relative to CTT. Data were analyzed via Mann-Whitney test.

Results

The Atmo Capsule was administered to 209 subjects (median age 41; 188 female) with 170 yielding valid data on both colonic transit and colonic gas concentrations. Delayed colonic transit was identified in 60/170 (35%) subjects. In subjects with delayed CTT, H₂ concentrations tended to be higher in the proximal colon and lower in the distal colon with no overall difference across the region compared with those with normal transit (Table 1). CO₂ concentrations were higher throughout the colon except in the distal colon in subjects with delayed CTT. Peak concentrations of colonic H₂ and CO₂ were higher (H2, 8.7 h vs 5.9 %.h/h, p<0.01; CO2, 37.4 vs 29.9 %.h/h, p<0.01) and tended to occur earlier (H₂, 35.9 vs 47.0 % of colonic transit p=0.14; CO₂, 49.1 vs 86.8 % colonic transit, p<0.01) in patients with delayed compared with normal CTT.

Table 1. Gas profiles in patients with delayed colonic transit and correlation with symptom profiles. Data shown as median (interquartile range) and analyzed via Mann-Whitney test.

Conclusion

Colonic gas profiles, as measured via the Atmo Capsule, differed in patients with delayed compared with normal CTT, with patterns suggesting progressive depletion of fermentable substrates and/or conversion of H2 to methane during transit in those with delayed transit.

References

Levitt MD, Furne JK, Kuskowski M, Ruddy J. Stability of human methanogenic flora over 35 years and a review of insights obtained from breath methane measurements. Clin Gastroenterol Hepatol. 2006 Feb;4(2):123-9. doi: 10.1016/j.cgh.2005.11.006. PMID: 16469670.

Disclosure

These authors disclose the following: Braden Kuo, Anthony J. Lembo, Eammon M.M. Quigley, Satish S.C. Rao, and William D. Chey serve on the Medical Advisory Board of Atmo Biosciences. Michael Cline and Baharak Moshiree served on the Medical Advisory Board of Atmo Biosciences. Braden Kuo has received funding from NIH, Vanda, Atmo Biosciences, and Takeda and has consulted for Evoke, Takeda, Ironwood, Novo Nordisk, Cindome, and Neurogastrx. Thomas Abell has received funding from Gastric Dysrhythmias, Neurogastrx, NIH GpCRC, and Vanda and has consulted for Enterra Medical, Novo Nordisk, Nuvaira, and Vanda. Anthony J. Lembo has received funding from Ardelyx, Biomerica, GSK, Ironwood, Takeda, and Vibrant and holds stock with Allurion, Bristol Myer Squibb, and J&J. Abigail Stocker has received funding from Cindome, Enterra Medical, and Vanda. William D. Chey has received funding from Atmo Biosciences, Commonwealth Diagnostics Intl, QOL Medical, and Salix; has consulted for AbbVie, Ardelyx, Biomerica, Comvita, Gemelli, Ironwood, Nestle, QOL Medical, Phathom, Redhill, Salix, Vibrant, and Takeda; has filed patents with My Nutrition Health, Digital Manometry, and Rectal Expulsion Device; and holds stock options with Coprata, Evinature, Food Marble, Kiwi Bioscience, and Modify Health. The remaining authors disclose no conflicts.