Medical comorbidity and distress in patients with irritable bowel syndrome: The moderating role of age

• IBS affects people of all ages and is comorbid with several medical conditions.
• Medical comorbidities affect psychological distress in patients with IBS.
• Medical comorbidities impact psychological distress more for younger IBS patients.
• Psychological distress may increase IBS burden and complicate treatment.

ObjectivesIrritable bowel syndrome (IBS) affects people across the age spectrum and is highly comorbid with other medical conditions. The aim of this study was to determine the moderating effect of age on the relationship between medical comorbidity and health outcomes in IBS patients.MethodsPatients (n = 384) across the age spectrum (18 to 70) completed questionnaires regarding medical comorbidities, anxiety, depression, IBS symptom severity, and IBS quality of life (QOL).ResultsThe mean age was 41 (SD = 15). Age interacted with medical comorbidities to predict anxiety, F(7,354) = 5.82, p = 0.009, R2 = 0.10. Results revealed significant main effects for education, β = − 0.16, p < 0.05, age, β = − 0.15, p < 0.05, medical comorbidities, β = 0.25, p < 0.05, and a significant interaction, β = − 0.15, p < 0.01. Anxiety was greater among patients with many comorbidities, with this effect being more pronounced for younger adults. Depression, also predicted by the interaction between age and comorbidities, showed the same pattern as anxiety. There was no significant interaction between age and medical comorbidities in predicting IBS symptom severity or IBS QOL.ConclusionDistress among IBS patients with medical comorbidities varies with age, with higher levels of anxiety and depression among younger adults than their older counterparts. Medical comorbidity may have a more selective impact on psychological distress as compared to IBS symptom severity and quality of life for younger adults with IBS. Distress may increase IBS burden for these patients and complicate its medical management.