Diamine oxidase as a biomarker for depression and disease activity in inflammatory bowel disease: A cross-sectional observational study

Figure 1 Comparison of serum diamine oxidase and d-lactate levels in inflammatory bowel disease patients with different disease severity and healthy controls. A: Diamine oxidase (DAO) and psychological symptoms; B: DAO and clinical activity; C: DAO and endoscopic activity; D: d-lactate (D-LA) and psychological symptoms; E: D-LA and clinical activity; F: D-LA and endoscopic activity. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. NS: Not significant; DAO: Diamine oxidase; D-LA: d-lactate.

Figure 2 Correlation analysis and receiver operating characteristic curves of serum diamine oxidase and d-lactate levels in patients with inflammatory bowel disease. A: Correlation analysis of diamine oxidase (DAO) and d-lactate (D-LA) with psychological questionnaires; B: Correlation analysis of DAO and D-LA with laboratory parameters; C: Receiver operating characteristic (ROC) curves of different biomarkers for diagnosing psychological symptoms; D: ROC curves of different biomarkers for diagnosing endoscopic activity; E: ROC curves of different biomarkers for diagnosing clinical activity. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. DAO: Diamine oxidase; QOL: Quality of life; GAD: Generalized anxiety disorder-7 scale; PHQ: Patient health questionnaire; PSS: Perceived stress scale; IBDQ: Inflammatory bowel disease questionnaire-32; CRP: C-reactive protein; ESR: Erythrocyte sedimentation rate; ALB: Albumin; AUC: Area under curve.