The diagnosis of functional dyspepsia (FD) is challenging due to the lack of reliable biological markers to support the diagnosis. We assessed the relevance of a previously validated simple test for chemical hypersensitivity in the setting of a gastrointestinal outpatient department.
A total of 224 outpatients who were referred for evaluation of gastrointestinal symptoms in the absence of alarm symptoms swallowed a capsule containing 0.75 mg capsaicin. Severity of symptoms before and after capsule ingestion was assessed by a graded questionnaire and the difference in aggregate symptom scores (delta) was calculated.
Sensitivity of the test was between 0.51–0.59, specificity was 0.84–0.89 and positive predictive value for the diagnosis of FD 70–71%. FD patients had significantly higher median delta symptom scores (10.0; 25% quartile: 3.0; 75% quartile: 16.0) as compared to inflammatory bowel disease (2.5; 1.0/8.5)(P=0.003), peptic ulcer disease (0.0; −1.5/4.5) (P<0.001), irritable bowel syndrome (3.0;0.5/8.5)(P=0.001), and patients classified with “other disease” (2.5;0.0/5.0)(P<0.001). Patients with gastroesophageal reflux disease had significantly lower symptom scores if FD was not concomitantly diagnosed (2.0; 0.0/6.0) than if FD was present (10.0; 4.0/15.0).
Hypersensitivity for capsaicin discriminates functional dyspepsia from patients with other GI disorders. The capsaicin test is a simple and non invasive method to detect a large subgroup of functional dyspepsia with chemical hypersensitivity. These findings might open new diagnostic options in functional dyspepsia and possibly new therapeutic options by targeting the specific capsaicin receptor TRPV1.
1Abteilung fìr Gastroenterologie und Hepatologie, Universitätsklinik fìr Innere Medizin 3, Vienna, Austria
Correspondence: Johann Hammer, MD, Abteilung fìr Gastroenterologie und Hepatologie, Universitätsklinik fìr Innere Medizin 3, Währinger Gìrtel 18–20, A-1090 Vienna, Austria. E-mail: Johann.Hammer@meduniwien.ac.at
published online 13 March 2018
Received 9 September 2017; accepted 21 November 2017