Acupuncture for functional constipation: protocol of an individual patient data meta-analysis

INTRODUCTION: Functional constipation (FC) is a common gastrointestinal disease. Systematic reviews indicate that acupuncture may be effective for patients with FC. However, this conclusion is not convincing due to the quality, sample size and methodological heterogeneity of the studies included by these systematic reviews. Therefore, it is necessary for us to conduct a meta-analysis of individual patient data (IPD) from high-quality clinical trials to determine whether acupuncture is effective for patients with FC. METHODS AND ANALYSIS: Randomised controlled trials (RCTs) of acupuncture for adult patients with FC will be searched in several databases from inception to April 2015. The corresponding authors of eligible studies will be contacted and invited to contribute raw data. The primary outcome is the change in spontaneous defaecation per week from baseline. The secondary outcomes include the proportion of responders, changes in stool quality, mean transit time, proportion of patients using laxatives and adverse events. We will check all of the data and perform reanalysis according to the statistical methodology reported in previous publications. Then we will harmonise the raw data and use a two-step method to conduct the IPD meta-analysis. First, we will calculate the effect size of acupuncture of each trial by analysis of covariance, with the principal end point as the dependent variable and the baseline scores as the covariates. Second, the effect size of acupuncture in each original study will be combined in the meta-analysis. DISSEMINATION: On the basis of the IPD meta-analysis of high-quality RCTs, this review will answer the question of whether acupuncture is effective for FC. The findings of the review will be disseminated through peer-review publications and conference presentations. TRIAL REGISTRATION NUMBER: PROSPERO 2014 CRD42014009901.