Objectives: Quality of life (QoL) improvement in patients with irritable bowel syndrome (IBS) during acupuncture (AC) treatment seems to be due to a placebo effect. The aim was to explore if acupuncture has some specific influence on the neuroendocrinic and autonomic nervous system (ANS).
Design/setting: Patients with IBS were randomly assigned to receive either acupuncture (AC) or sham acupuncture (SAC) using the so-called "Streitberger needle". QoL was measured with the functional quality of life diseases quality of life questionnaire (FDDQL) and SF-36. The effect on ANS was evaluated by measuring salivary cortisol and by cardiovascular responses on a tilt table before and after 10 AC treatments. Complete data sets of tilt table and salivary morning cortisol were available for 9 patients in the AC and 12 in SAC group.
Results: QoL increased in both groups (p=0.001) with no group differences. Salivary cortisol decreased in all groups (F=10.55; p=0.006). However, the decrease was more pronounced in the AC group (F=4.07; p=0.033) (ANOVA repeated measures model). Heart rate response decreased during orthostatic stress in the AC group while it increased in the SAC group (F=9.234; p=0.005), indicating an increased parasympathetic tone in the AC group. Improvement of pain was positively associated with increased parasympathetic tone in the AC group (F=10.1; p=0.006), but not in the SAC group.
Conclusions: The acupuncture specific physiological effects are in contrast to the unspecific improvement of QoL in both AC and SAC groups. Thus, different mechanisms seem to be involved in placebo and real-acupuncture driven improvements. The specific mechanism of action of acupuncture on the ANS remains unclear and deserves further evaluation.