Background: Placebo effects emerging from expectancies of relatives, also known as placebo by proxy, is a rather unexplored field. In this study, we assume a correlation between parental anxiety/expectancy and postoperative morbidities in children. Accordingly, a reduction of parental anxiety is expected to enhance the effect of treatment.
Methods: From October 2012 to June 2013, parents of 282 children completed a self-report closed-ended questionnaire embedded in a main RCT at three ambulatory care centers.
Results: There were no significant associations between parental expectancy or anxiety and children experiencing vomiting and pain.
Conclusion: The present study is the first to investigate placebo by proxy in acupuncture treatment for children. The findings were not able to demonstrate any placebo effect by proxy. Unknown confounders and limitations of methods may have contributed to the negative findings. Thus, the findings must be read with precaution, as the possibility of a type II error cannot be excluded.
Trial registration: ClinicalTrials.gov NCT01729052.
© 2015 S. Karger GmbH, Freiburg.