Symptom duration in patients with irritable bowel syndrome

The etiology and natural history of irritable bowel syndrome (IBS) is poorly understood. We compared rectal sensory thresholds and compliance, SCL-90 scores, and follow-up questionnaires among normal controls, patients with longstanding ( > 5 y) disease (L-IBS), and patients with recent onset ( > 2 y) disease (R-IBS). The onset of symptoms in R-IBS was related to specific events such as infection (n = 10), surgery (n = 5), and stress (n = 4), but no specific event could be identified in six patients.

A diagnosis of IBS was made using Manning criteria ( > or = 3) and clinical grounds. Psychological data were obtained by psychometrics (SCL-90) scores. Rectal wall compliance and thresholds for the sensation of stool and discomfort were evaluated using the electronic barostat.

The mean thresholds for phasic and ramp distention were similar for R-IBS and L-IBS groups for the perception of stool and discomfort. When compared with normals, the mean stool thresholds for phasic distention were significantly lower for L-IBS and R-IBS groups. SCL-90 scores were significantly increased in L-IBS in the mean phobia score (45 R-IBS vs 61 L-IBS), anxiety score (49 R-IBS vs 63 L-IBS), paranoia score (44 R-IBS vs 60 L-IBS), and hostility score (47 R-IBS vs 61 L-IBS) (all p < 0.05). On follow-up questionnaire, 60% of R-IBS versus 46% of L-IBS patients indicated that their symptoms had improved (p < 0.05). R-IBS patients also experienced fewer episodes of abdominal pain per week at follow-up than L-IBS patients (3.9 +/- 1.0 vs 8.5 +/- 1.7, respectively) (p < 0.05).

Our findings suggest that IBS patients with short symptom duration and fewer psychological symptoms have a better prognosis than patients with a long history of IBS and associated psychological distress, although long term prospective studies are needed.