Introduction

Irritable bowel syndrome patients frequently suffer from comorbid mental (anxiety or depression) or somatic (fibromyalgia or chronic fatigue) conditions. In this pan-European project (the DISCOvERIE project), IBS patients with and without comorbidities were compared with disease controls and healthy controls, to further elucidate the effect of comorbid conditions in IBS on the disease burden.

Aims & Methods

We included participants from nine different European centers – IBS patients according to Rome IV criteria, disease controls (patients with comorbid conditions; i.e. fulfilling diagnostic criteria for anxiety, depression, fibromyalgia and/or chronic fatigue, but no IBS) and healthy controls. The participants were further divided into eight groups based on presence or absence of comorbitidies: IBS with no/ mental/ somatic/ mental and somatic comorbidity, disease controls with mental/ somatic/ mental and somatic comorbidity, and healthy controls. The severity of IBS symptoms (IBS-SSS), depression (PHQ-9), anxiety (GAD-7), somatic symptoms (PHQ-15), fibromyalgia symptoms (FIQ) and general and mental fatigue (MFI) were compared between these groups.

Results

In total, 849 participants (median age 44 years) were included. A majority were females (76%), with the most pronounced female predominance (83%-86%) in the IBS groups with comorbidities. The most severe IBS symptoms were noted among IBS with both mental and somatic comorbidity and IBS with somatic comorbidity (Table 1). In IBS, the severity of IBS symptoms increased gradually with increasing number of comorbidities (partial eta squared: 0.053, p<0.001), as did severity of anxiety, depression, somatic symptoms and general fatigue (partial eta squared: 0.214, 0.247, 0.240, 0.239, respectively, all p<0.001). The groups with both mental and somatic comorbidity had the highest levels of anxiety, depression and mental fatigue. Somatic symptoms and general fatigue were most severe among IBS and disease controls with somatic comorbidity or both somatic and mental comorbidity. Fibromyalgia symptoms were most severe in IBS and disease controls with somatic comorbidity.

Table 1: Symptom severity of the study groups.

Conclusion

This large European multicenter study strengthens the importance of the impact of mental and somatic comorbid conditions and symptoms in IBS, and their influence on outcomes and disease burden.

Disclosure

Hans Törnblom: Consultant or advisory board member for Allergan, Cinclus Pharma, Medifactia, and VIPUN and as a speaker for Tillotts, Takeda, and Shire.

Daisy Jonkers: Part of the work of DJ, outside the submitted work has been financed by public-private partnership grants of Top Knowledge Institute (TKI) Agri&Food and Health Holland, by the Carbokinetics program as part of the NWO-CCC Partnership Program, by Organic A2BV/Mothersfinest BV.