Eligible participants were aged 18 years or older and met Rome III criteria for functional constipation, namely, experiencing two or more of the following criteria for the last 3 months with symptom onset at least 6 months prior to diagnosis: straining during at least 25 % of defecations; lumpy or hard stools in at least 25 % of defecations; sensation of incomplete evacuation for at least 25 % of defecations; sensation of anorectal obstruction/blockage for at least 25 % of defecations; manual maneuvers to facilitate at least 25 % of defecations (e.g., digital evacuation, support of the pelvic floor); and fewer than three defecations per week. Patients were excluded if they were pregnant, if they experienced significant weight loss (more than 10 % of their usual body weight in the preceding 6 months), and if they had a history of blood mixed in stool. The perineal self-acupressure for constipation (PSAC) study protocol was approved by the institutional review board at UCLA (IRB#13-000738) and registered with ClinicalTrials.gov (Identifier: NCT01867944), and all participants provided written informed consent.
Study Design and Treatment
The study was a randomized, parallel group trial, with each eligible participant randomly assigned to either standard care (control) or standard care plus perineal self-acupressure (treatment). Potential participants were recruited from the local community and screened by phone from July 2013 to April 2014. Eligible participants who met all study criteria were enrolled on a rolling basis after they arrived at UCLA to complete the informed consent process and baseline survey instruments. Patients unable to travel to UCLA were given the option to meet with study personnel in their homes or at a public place of their choosing. With 50 patients per group and with 20 % of patients lost to follow-up, we projected 90 % power to detect a clinically meaningful change in the PAC-QOL total score of 0.5 (given a population mean of 1.85 and a SD of 0.6718).
Computer-generated randomization was not stratified, with treatment assignments made in random permuted blocks of size 2. Subjects in both groups received educational materials about constipation and conventional treatment options (e.g., increased dietary fiber intake, stool softeners, increased exercise). Subjects in the perineal self-acupressure group also received sex-specific educational material and training in perineal self-acupressure. Training consisted of 3 to 5 min of oral instruction on how to apply perineal pressure, with the aid of a plastic anatomic model displaying the perineal region. Subjects in the perineal self-acupressure group were not restricted from using standard care. All of the patient materials appear in Online Appendix 2. All participants completed an initial set of survey instruments immediately following the informed consent process. One month after completing the initial set of survey instruments, subjects in both groups were asked to return a follow-up set of survey instruments. The last participant completed follow-up in June 2014.
The primary outcome measure was patient assessment of constipation-related health quality of life by means of the Patient Assessment of Constipation Quality of Life Questionnaire (PAC-QOL). The validated PAC-QOL is composed of 28 items grouped into four subscales: physical discomfort, psychosocial discomfort, worries and concerns, and satisfaction.18 The first three subscales comprise the patient dissatisfaction index, with an overall score ranging from 0 to 96 (where higher scores correspond to worse quality of life). The satisfaction subscale includes four items that produce a combined score ranging from 0 to 16, with scores defined as poor (0–4), fairly good (5–8), good (9–12), or excellent (13–16).
Secondary measures were a modified version of the Bowel Function Index (BFI) for patient self-completion, original questions to measure change in hemorrhoid impact, the Short Form Health Survey version 2 (SF-12v2), and original questions (for the perineal self-acupressure group only) regarding use and effectiveness of the technique and associated educational materials. The modified BFI was a three-item questionnaire that measured bowel symptoms by asking patients to rate ease of defecation, feeling of incomplete bowel evacuation, and constipation on a scale from 0 to 100 (where higher scores indicate greater disease impact).19 The hemorrhoid questions asked participants whether they had experienced new episodes with hemorrhoids in the last 4 weeks, and to rate bleeding, itching, and pain associated with hemorrhoids during that time frame. The SF-12 is a validated multipurpose short survey with 12 questions, all selected from the SF-36 Health Survey.20 Physical and Mental Health Composite Scores (PCS & MCS) are computed using the scores of 12 questions and range from 0 to 100, where higher scores indicate better quality of life. Finally, the perineal self-acupressure group was asked a series of open and closed-ended questions related to their use of perineal self-acupressure, its perceived effectiveness, their desire to continue using the technique and to recommend it to others, and the effectiveness of the educational materials. All patient survey instruments appear in Online Appendix 3.
Analyses were based on the intention-to-treat method in all randomized participants. Missing outcomes during the follow-up period were imputed using the last-observation-carried-forward method. To assess the robustness of the analytical results under alternative imputation methods, analyses were repeated on all outcomes using multiple regression imputation as well as available data only (no imputation). Results did not differ between these two methods and the last-observation-carried-forward method. Treatment effects were also estimated using Seemingly Unrelated Regression (SUR), Ordered Logit, and Instrumental Variables regressions. Potential interactions between treatment and other factors, also used to assess heterogeneity of results across subgroups, were also tested with patient fixed-effect and difference-in-difference regressions. See Online Appendix 4. All reported confidence intervals (CIs) were two-sided 95 % intervals, and tests were two-sided with a 5 % significance level. All analyses were performed with STATA version 13 (Stata Corp, College Station, Texas).