P0186 - A Retrospective Look at Gastrointestinal Amyloidosis and Correlations to Congo Red Positivity

Rex Siu, MD, MSc¹, Paul Travers, MD², Timothy A. Woodward, MD¹, Maoyin Pang, MD, PhD^1
1Mayo Clinic Florida, Jacksonville, FL; ²Mayo Clinic, Jacksonville, FL

Introduction: Gastrointestinal (GI) symptoms in patients with amyloidosis are poorly characterized which presents as a diagnostic conundrum and delays recognition and care optimization. The purpose of this study was to investigate amyloidosis disease course and clinical presentation to elucidate correlations that may allow earlier recognition of GI amyloidosis.

Methods: Adult patients with amyloidosis were identified at a tertiary care academic center between 2012 and 2022. Demographic, comorbid, endoscopic, and clinical data was collected retrospectively. Clinical data included presenting symptoms, biopsy location, and endoscopic findings. We examined the collected data for correlations with congo red positivity. Statistical analysis was performed using univariate linear regression.

Results: We identified 220 adult amyloid patients of which 85 were evaluated for GI amyloidosis via endoscopy. 75 (88.2%) showed congo red positivity on GI biopsy. In the cohort of 85 (30.6% female, 88.2% Caucasian) with a median age of diagnosis of 65 (range 39-89), it was revealed that biopsies in the esophagus (OR 1.19, Z 0.10, p 0.91), stomach (0.89, Z -0.0753, p 0.94), duodenum (OR 0.024, Z -1.71, p 0.086), ileum (OR 0.025, Z -1.4, p 0.16), colon (OR 4.99, Z 0.875, p 0.381), and rectum (OR 0.14, Z -1.02, p 0.307) had no correlation to congo red positivity. Endoscopic findings like colitis (OR 4.6E8, Z 0.003, p 0.99), gastritis (OR 1.04E8, Z 0.002, p 0.99), and normal mucosa (OR 0.121, Z -1.42, p 0.15) did not correlate with congo red positivity either. The presenting symptoms that led to evaluation, including dysphagia (OR 0.5, Z -0.51, p 0.6), anorexia (OR 229, Z 0.001, p 0.99), reflux (OR 3.56E9, Z 0.003, p 0.055), diarrhea (OR 0.45, Z -0.44, p 0.65), nausea/vomiting (OR 0.01, Z -1.92, z 0.33), and abdominal pain (OR 4.78, Z 0.25, p 0.33) also showed no correlation. Demographic data also revealed no significance in relation to congo red positivity.

Discussion: This retrospective study investigated key areas including symptom presentation, biopsy location and endoscopic findings to characterize correlations to congo red positivity and we observed that these do not show correlations. This leads us to believe the approach to those suspected of GI amyloid may need broad biopsy even with normal gross appearance to prevent false negatives. Larger scale studies will need to be performed to accurately assess the generalizability of these findings to other races and women.


Disclosures:


Rex Siu, MD, MSc¹, Paul Travers, MD², Timothy A. Woodward, MD¹, Maoyin Pang, MD, PhD¹. P0186 - A Retrospective Look at Gastrointestinal Amyloidosis and Correlations to Congo Red Positivity, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.