Psychobiological subtypes of ulcerative colitis: pANCA status moderates the relationship between disease activity and psychological distress.

Introduction: Studies of psychological factors in ulcerative colitis (UC) have produced inconsistent findings. This study sought to determine whether perinuclear antineutrophil cytoplasmic antibody (pANCA) demarcates subtypes which differ with respect to psychobiological interactions.

Methods: In 148 outpatients with UC, the strength of the relationship between current UC disease activity and psychological distress was assessed. pANCA was determined by ELISA and immunofluorescence, disease activity was determined by symptoms, physical examination, and endoscopy using the St. Mark's index, and depressive symptoms and health anxiety were measured with self-report scales. Pearson correlations between disease activity and depressive symptoms and between disease activity and health anxiety were calculated.

Results: In 74 pANCA negative subjects, the relationship between disease activity and measures of psychological distress was significant for disease activity-depression (partial correlation = 0.48, p < 0.001) and for disease activity-health anxiety (partial correlation = 0.64, p < 0.001), whereas in 74 pANCA positive subjects, no relationships were found (disease activity-depression: partial correlation = 0.18, p= 0.14; disease activity-health anxiety: partial correlation = 0.20, p= 0.09). The differences in the strength of correlation between pANCA positive and pANCA negative subjects were statistically significant for both disease activity-depression (z = 2.0, p= 0.02) and activity-health anxiety (z = 3.3, p < 0.001).

Conclusions: pANCA status demarcates psychobiologically distinct subtypes of UC, such that the absence of pANCA is associated with greater psychobiological interaction. These findings have implications for clinical care and understanding the pathophysiology of intestinal inflammation.