Dyspepsia

The RDQ is a self-administered questionnaire in which subjects are asked to report the frequency and severity of their upper gastrointestinal symptoms. There are three subscales that evaluate regurgitation, heartburn, and dyspepsia [3 (link)]. The heartburn and regurgitation subscales can be combined into a GERD dimension. In the published survey, the time referent is symptoms that have occurred over the last four weeks. In this study, the time referent was the last four weeks at baseline, but one week at the post-treatment visit (visit 2, after two weeks of treatment). Item content includes the following: 1) four items on the frequency and severity of acid taste in the mouth and movement of materials upwards from the stomach (Regurgitation scale); 2) four items measuring the frequency and severity of pain or burning behind the breastbone (Heartburn scale); and 3) four items on the frequency and severity of pain or burning in the upper stomach (Dyspepsia scale). Response options were scaled as Likert-type with scores ranging from 0 to 5 for frequency (not present to daily) and severity (not present to severe). Each subject's score was calculated as the mean of item responses with higher scores indicating more severe or frequent symptoms. The psychometric properties of the RDQ are described in more detail by Shaw and colleagues [3 (link)].

The Korea Constitutional Multicenter Study (KCMS) is an ongoing project designed to establish a database for SCM [35 ]. Currently, 3,711 participants are enrolled from 24 Korean medical clinics (KMCs) since August 2012. The KCMS was approved by the Institutional Review Board at the Korea Institution of Oriental Medicine (KIOM) (I-0910/02-001). The Korea Constitutional Multicenter Bank (KCMB) is a biobank linked to phenotypic data from KCMS. Figure 1 shows the distribution of hospitals contributing to this study. The hospitals are distributed fairly evenly amongst the different regions of Korea, and the study population represents the entire population of Korea. Figure 1 also shows a concentration of 11 hospitals in a population-dense area where approximately 20% of the Korean population resides.Figure 1

Distribution of hospitals that participated in the KCMS.

All participants in the KMCS have had documented responses to herbal medicine as confirmed by Korean medicine doctor (KMD). In order to diagnose the SC type, each participant was prescribed a SC-specific herbal remedy for the treatment of their most prominent physical discomfort [21 (link)]. After taking the medicine for 30 days or more, improvement of original symptoms and occurrence of adverse effects were recorded. The SC types were determined only for participants who had an obvious improvement in their chief complaints without experiencing any adverse effects such as indigestion, stomachache, and evacuation troubles. Every hospital recruited participants within their respective patient population. To ensure the accuracy of the diagnoses, practitioners who took part in this study were restricted to those who had more than 5 years of experience in clinical practice. A more detailed description of the verification methodology and procedure of SC types that we used have previously been reported in [35 ].

All the statistical analysis was performed by STATA Software version 16.0. The GSRS Indigestion subscale score, global evaluation of patient scores, and other cumulative subscale scores in the GSRS questionnaire were represented as continuous variables.
A comparative analysis was performed for normally distributed data within the group, and the results were presented as mean, standard deviation/standard error, and P value. For nonnormally distributed data within the comparative group, analysis was performed using the Wilcoxon Signed-Rank test. The results were presented as median, range, and P value. An unpaired t test/Mann-Whitney test was performed for the comparative analysis between treatment groups. The level of statistical significance for each test is defined as P < .05. Other secondary endpoints, Bristol stool analysis, brain fog questionnaire, and the occurrence of adverse events, were presented as categorical variables. A descriptive comparison was provided to differentiate the treatment effects between the treatment groups and within treatment groups.