Background
Abdominal pain is a common but often overlooked symptom in patients with ulcerative colitis (UC). The causes of pain during deep remission remain incompletely known, although factors in the gut-brain axis may play a role. The aim of this study was to investigate the prevalence of abdominal pain in active and quiescent UC patients as well as associated factors.

Methods
Three existing study cohorts of adults with UC were used. Cross-sectional cohort I included 130 patients (84 quiescent), cross-sectional cohort II 288 patients (132 quiescent) and longitudinal cohort III 83 patients (data from time of diagnosis (with active disease) compared to the first visit with quiescent disease). Quiescent UC was defined based on clinical judgement in cohort I and as total Mayo score ≤ 2, with rectal bleeding, endoscopic and physician global assessment sub scores of 0 and fecal calprotectin ≤200 µg/g (not available for all) in cohort II and III. The abdominal pain question of the Gastrointestinal Symptom Rating Scale was used to assess the severity of pain, ranging from no to very severe using a 7-point Likert scale. The Hospital Anxiety and Depression Scale was used to score severity of anxiety and depression, whereas the Fatigue Impact Scale (cohort I) and Multidimensional Fatigue Inventory (cohort II) were used to score fatigue. For quality of life (QoL), the Short Form Health Survey-36 (cohort I) and the IBD Questionnaire (cohort II) were used. The Jonckheere-Terpstra Test was used to test for statistically significant trends of the different scores with an increase of abdominal pain.

Results
In the two cross-sectional cohorts, 48% and 43% patients with active disease and 30% and 21% of the patients in remission reported abdominal pain of at least mild severity. In the longitudinal cohort III, 49% reported at least mild severity of abdominal pain at UC diagnosis vs 27% once in remission (p<0.001). However, 13% had even higher abdominal pain levels once in remission compared to time of diagnosis (Figure 1). In cohort I and II, more severe abdominal pain in quiescent UC patients was associated with more severe anxiety (p<0.001), depression (p<0.05), and fatigue (p<0.001) and reduced QoL (p≤0.01). The same associations were seen for active UC patients in cohort II (all p≤0.001), but no significant associations for the active UC patients in cohort I (Table 1).

Conclusions
Abdominal pain is common in patients with UC and persists in a proportion of the patients also when they are in remission. Having abdominal pain is associated with more severe psychological symptoms and fatigue and reduced QoL in active and quiescent UC. Hence, paying attention to abdominal pain and associated factors seems important to optimize clinical management.

<b>Figure 1.</b> Sankey diagram of the intraindividual flow of abdominal pain levels over time from diagnosis (i.e. active UC) to the first visit with quiescent UC.

Figure 1. Sankey diagram of the intraindividual flow of abdominal pain levels over time from diagnosis (i.e. active UC) to the first visit with quiescent UC.

<b>Table 1.</b> Scores for anxiety, depression, fatigue, and quality of life across different levels of abdominal pain.

Table 1. Scores for anxiety, depression, fatigue, and quality of life across different levels of abdominal pain.

Börje Jonefjäll

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