The disease severity index for inflammatory bowel disease is associated with psychological symptoms, quality of life and predicts a more complicated disease course

Background/Aims The Disease Severity Index (DSI) is a novel tool to predict disease severity in inflammatory bowel disease (IBD). However, its ability to predict disease complications and the presence of psychosocial comorbidity is unclear. This study prospectively assessed associations between the DSI and psychological symptoms, quality-of-life (QoL) and disease outcomes in an IBD cohort. Methods Patients with IBD undergoing ileocolonoscopy were followed prospectively for 12 months. DSI, psychological symptoms (perceived stress (PSS-10), depression (PHQ-9), anxiety (GAD-7)) and QoL (IBDQ-32) scores were assessed at baseline. Logistic regression identified variables predicting a complicated IBD course at 12 months (composite outcome of need for escalation of biological/immunomodulator for disease relapse, recurrent corticosteroid use, IBD-related hospitalisation and surgery). Receiver operating characteristics (ROC) analysis identified optimal DSI thresholds predicting a complicated disease course and multivariable logistic regression assessed the risk of reaching this outcome. Results One hundred and seventy-two patients were recruited (100 Crohn's disease, 91 female). Median DSI was 21 (IQR 11-32) and 97 patients had endoscopically active disease at baseline. The DSI was significantly higher in patients with symptoms of moderate-severe stress (PSS-10 > 14, p < 0.01), depression (PHQ-9 >= 10, p < 0.01), anxiety (GAD-7 >= 10, p < 0.05) and impaired quality-of-life (IBDQ-32 < 168, p < 0.01). Only the baseline DSI (OR 1.05, p < 0.01) and endoscopically active disease (OR 6.12, p < 0.01) were associated with a complicated IBD course. A DSI > 23 was strongly predictive of a complicated IBD course (OR 8.31, p < 0.001). Conclusions The DSI is associated with psychological distress, impaired QoL and predicts a more complicated disease course in patients with IBD.