Analysis of clinical characteristics of centrally mediated abdominal pain syndrome, exploration of diagnostic markers and its relationship with the efficacy of duloxetine treatment

Centrally mediated abdominal pain syndrome (CAPS) is characterized by severe abdominal pain. Diagnosis of CAPS is still an exclusionary diagnosis, there remain no effective diagnostic biomarkers so far. Duloxetine is the major pharmacotherapy of CAPS, while some CAPS patients do not respond to duloxetine treatment. However, there is a lack of molecular markers to predict the efficacy of duloxetine. In our pilot study, we have found differential expression profiles of serum miRNAs between CAPS patients and healthy controls. Our study aims to explore the clinical characteristics, specific miRNAs in serum as diagnostic biomarkers of CAPS and predictive biomarkers of the efficacy of duloxetine. METHODS/DESIGN: In this prospective cohort study, we plan to enroll 430 participants including 215 CAPS patients and 215 healthy controls. The CAPS group takes duloxetine 30 mg per day as an initial dose. Patients will have 24-week medication period and follow up at week 0, 4, 12, 24 and 36. Blood samples will be obtained from patients at every visits and health controls at the initial visit and a series of questionnaires will be completed by the participants. The primary end points are: The differential expression of miRNAs between CAPS groups and healthy control groups at baseline. The changes in abdominal pain scores before and after duloxetine treatment in patients with CAPS and their relationship with the changes in miRNAs. The secondary end point is the changes in scores of depression, anxiety, sleep quality and quality of life before and after duloxetine treatment in patients with CAPS and their relationship with changes in miRNAs. DISCUSSION: Findings of study will provide the reliable basis for diagnosis and the predictor of duloxetine efficacy of CAPS. Importantly, findings grant patients a chance to benefit from treatment.