PATIENTS WITH ULCERATIVE COLITIS (UC) DEMONSTRATE ABNORMALITIES OF AUTONOMIC FUNCTION WHICH ARE CORRELATED WITH MEASURES OF ANXIETY

SC Ganguli, MC Kamath, M Mohammed, Y Chen, EJ Irvine, SM Collins, G Tougas

McMaster University Medical Centre, Hamilton, Ontario

INTRODUCTION: Abnormalities of the autonomic nervous system (ANS) reported in patients with inflammatory bowel disease (IBD) have been inconsistent. Stress has also been implicated in exacerbation of IBD. The aim of our study was to compare autonomic function in patients with UC, Crohn’s (CD), and age matched healthy controls using Power Spectral Analysis of Heart Rate Variability (HRV) and to examine its relationship to stress.

METHODS: UC or CD outpatients underwent HRV testing and filled questionnaires: disease activity, quality of life (IBDQ), anxiety or depression (Hospital anxiety and depression scale [HAD], State-trait anxiety inventory [STAI]). Outcomes included heart rate, and low frequency (LF;0.03-0.15 Hz) and high frequency (HF;0.18-0.40 Hz) activity (absolute and percentage area of HRV).

RESULTS: 24 patients (12 UC, 12 Crohn’s) were enrolled. Compared to controls, UC patients had greater % LF area (71.0±5.8% [mean±SD] vs 61.7±6.3%; P<0.01) reflecting greater sympathetic tone, and decreased absolute and % HF area (2862±835 vs 4253±905;P<0.01 and 29.0±5.8% vs 38.3±6.3%; P<0.01) consistent with lower resting parasympathetic activity. UC patients with distal colitis (n=7) had more LF area than those with pancolitis (n=3) (6793±553 vs 5640±276; P=0.01) reflecting greater sympathetic tone. Crohn’s patients were not different from controls in any HRV parameters. In UC patients, greater disease activity as measured by symptoms (R=0.787; P<0.01) and IBDQ (R=-0.69; P=0.013) was correlated with greater sympathetic activation (absolute LF area). Anxiety was strongly correlated with the absolute LF area (HAD A R=0.88;P<0.01 and STAI trait R=0.75; P<0.01). UC patients had greater absolute and % LF area in comparison to CD (6454±660 vs 5755±788; P=0.03 and 62.5±9.6% vs 54.0±8.9%; P<0.05)

CONCLUSIONS: 1) Patients with UC have greater sympathetic autonomic activity than healthy controls or Crohn’s patients. 2) UC patients with proctitis have greater sympathetic tone than those with pancolitis. 3) In UC, the degree of sympathetic activation correlates with symptom severity and measures of anxiety. 4) It is unclear if autonomic and mood changes modulate disease expression or are due to symptoms. 5) These preliminary observations need to be further studied.

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