Effect of self-management intervention on cortisol and daily stress levels in irritable bowel syndrome

Abstract

Self-management programs that include cognitive behavioral strategies have been shown to improve gastrointestinal (GI) symptoms, psychological distress, and quality of life (QoL) in persons with irritable bowel syndrome (IBS). However, less is known about the physiological impact of such a change. As part of a randomized controlled trial using a comprehensive self-management (CSM) intervention (n = 126) compared to usual care (UC; n = 62), cortisol levels were measured in 4 weekly first morning urine samples at baseline and at 3-, 6-, and 12-month follow-up. In addition, diary (28 days) ratings of stress were recorded at baseline, 3, 6, and 12 months. The omnibus test of all three outcome times showed no differences in urine cortisol levels between the CSM and UC groups (p = .400); however, at 3 months the CSM group had significantly higher cortisol levels than the UC group (p = .012). The CSM group reported lower daily stress levels (p = .046 from the omnibus test of all 3 time points) than the UC group, with the effect getting stronger over time. Despite marked improvements in reported stress and previously reported GI and psychological distress symptoms at later follow-ups, the CSM program did not reduce urine cortisol levels in adults with IBS. These results suggest that the first-void urine cortisol levels are not reflective of self-reported daily stress in this patient population.

Figure 1

Mean (95% CI) of change in log₁₀ of cortisol levels (ng/mg creatinine) in urine from baseline across three follow-up assessments in the comprehensive self-management and the usual care groups. The dotted line at zero represents no change from baseline cortisol levels.

Figure 2

Mean (95% CI) of change in percent of days with moderate-to-very severe stress levels from baseline across three follow-up assessments in the comprehensive self-management and the usual care groups by daily self report. The dotted line at zero represents no change from baseline percent of days with moderate-to-very severe stress levels.

Figure 3

Mean (95% CI) on log₁₀ of cortisol levels (ng/mg creatinine) at baseline in women and men. The number of subjects is in the parentheses next to each gender. No significant difference was found after controlling for baseline creatinine and age.