Clinical implications of gastrointestinal symptoms in systemic amyloidosis

Abstract Background Gastrointestinal ( GI ) symptoms in systemic amyloidosis patients are poorly characterized. This purpose of this study is to define the epidemiology and clinical implications of such symptoms. Methods This was a retrospective cohort study of 583 amyloid patients seen at a tertiary referral center. Of 96 symptomatic patients, 82 received endoscopic biopsies, subsequently grouped into those with histologic evidence of GI amyloid (biopsy proven) vs without (biopsy absent). Key Results 16.8% of patients had GI symptoms, and had more abnormal NT ‐pro BNP , cardiac ejection fraction, serum albumin, and alkaline phosphatase ( P < .01). Of those who received endoscopy, the sites of highest diagnostic yield were stomach, duodenum and colon. The most common symptom was abdominal pain, nausea, or vomiting (50.0%). Of the symptomatic patients, only 37 (45%) had biopsy proven GI amyloid. Biopsy proven patients more often had cardiac involvement ( P < .005), and more often received hematologic therapy or transplant ( P = .01). Biopsy absent patients had more frequent neurologic involvement ( P = .17). Biopsy status had no significant correlation with other indicators of amyloid burden, GI symptoms or management. Conclusions & Inferences Nearly one in six amyloid patients have GI symptoms, and half do not have GI amyloid. The type of symptom does not predict endoscopic findings. Most biopsy absent patients are not managed as a functional disorder despite no alternative etiology. Gastroenterologists may have an increased role to play in the care of systemic amyloidosis beyond performing endoscopies, such as evaluating cardiac amyloid patients for concurrent GI amyloid.