Patients and Methods
This study mainly investigated the curative effects and possible mechanism of SGR on CAD patients. In this study, patients with CAD were randomly assigned to the case group and control group; the patients in case group received SGR, and those in the control group received placebo twice-daily for 6 months. As soon as the patients were recruited to the trial, they underwent laboratory examinations and fulfilling SAQ. The laboratory examinations mainly included alanine amino transferase (ALT), aspartate amino transferase (AST), blood urea nitrogen (BUN), serum creatinine level, and blood lipids. The patients were followed-up for 12 months with repeated questionnaires for every 3 months. At 6 months follow-up, the participants underwent repeated laboratory examinations, including coronary computed tomography angiography (CCTA). At the beginning of the study, all patients signed informed consent forms, which were informed about the risks and benefits of the treatment strategy. A flow diagram of the trial is shown in Figure1.
Inclusion and Exclusion Criteria
The inclusion criteria were as follows: (1) the age of the subjects should be over 18 and less than 75 years old; (2) living in Guangdong province for long-time (total duration of residency > 3 years, annual duration of residency > 9 months); (3) patients were aware of the study and agreed to sign informed consent forms; (4) patients had been diagnosed with CAD by clinical manifestations
and examinations, and CCTA showed 50-70% of coronary atherosclerotic stenosis, with soft plaque or mixed plaque; (5) the patients did not undergo PCI surgery and coronary artery bypass grafting (CABG); (6) Phlegm and blood stasis syndrome (PBSS) due to syndrome of qi deficiency. Syndrome differentiation will be determined by two qualified TCM cardiologists dependently according to diagnostic criteria for TCM differentiation (Table1).
The exclusion criteria were as follows: (1) patients were complicated with other serious diseases, including malignant tumor, severe infection, and other significant life-limiting comorbidities; (2) pregnant and lactating women and those allergic to TCM; (3) poor compliance, and failure to visit regularly; (4) Valvular heart disease; (5) patients with congenital metabolic abnormalities or immune diseases.
The included patients have the right to stop treatment and withdraw from the research project for any reason at any time, and the reason why they want to quit the research project will be recorded
in their CRF. Participants who do not complete the research project with the following reasons should be considered as dropped out. (1) The patient chooses to quit the research project. (2) loss to
follow-up. (3) Poor compliance. (4) The participant develops another severe disease that needs to
be treated during the study.
In order to recruit patients, advertisements were placed in a broad range of media outlets, including the flyers within the hospital, as well as website of Chinese Clinical Trial Registry. Patients who were interested in the trial received information about the study. Each potential participant was informed that the participation is fully voluntary and refuse to participate in the research has no negative effect on their treatment. Those who would like to join the study were later assessed to determine whether they meet the inclusion criteria or not.
Randomization and Blinding
A random number generator in SAS 6.12 software (SAS Institute, Cary, NC, USA) was used to generate a random number in a 1:1 randomization ratio by DME (Design, Measurement, and Evaluation in Clinical Research) Center of Guangzhou University of Chinese Medicine (Guangzhou, China). The research team members, except for the clinical research methodology personnel, will be blinded to the treatment and the group assignment. Participants were informed about the information of case group and control group, while were not told their group assignment, thereby allowing blinding of the participants between the treatment groups. Both the SGR and placebo granule were manufactured by the Jiangyin Tianjiang Pharmaceutical Co., Ltd. (Jiangyin, China), and the placebo was identical compared with SGR in color, size, shape, and taste. The study code will not be revealed until the end of the study, unless there is a serious adverse event (AE).
After a recruitment period prior to baseline assessment, the included participants were randomized to the case group and control group, in which the patients in case group received SGR and those in the control group received placebo (6 g/day for 6 months). Simultaneously, the included patients also received usual care according to patients' conditions, including aspirin, clopidogrel, angiotensin converting enzyme inhibitors or beta-blockers, calcium channel blockers, and nitrate esters irrespective of the initial randomization assignment. All the treatments were under the responsibility of physicians according to the clinical guidelines. Study medication (including both placebo and SGR) will be dispensed by the Hospital Central Pharmacy as a set of boxes at the beginning of each study month. In order to check the compliance of patients, the patient was asked to bring the box back. The treatment prescriptions and conditions of patients were recorded in the case form. Details of study procedures of the trial are given in Table 2.
Before starting the intervention, at 3 months intervention, after completing the intervention (6 months after treatment), and 1 year intervention, all the patients had to complete a questionnaire related to quality of life. Additionally, all the patients underwent laboratory examinations and CCTA at baseline (prior to starting either intervention) and at 6 months follow-up. During the follow-up period, any enrolled participants who were unable to continue the study during the treatment remained in their randomized group to perform intention-to-treat (ITT) analysis.
The primary endpoint of the study was CCTA, that mainly included calcium coverage score (CCS). CCS represents the percentage of coronary arteries affected by calcific plaque, which was detected with cardiac CT (CCT). CCS has been shown to be reliable, reproducible, and predictive of cardiovascular risk, and also was highly associated with the risk of CAD[14-16]. A study revealed that a twofold increase in CCS was associated with a 34% (P＜0.001) increase in the risk of a hard CAD event, in addition to a 52% (P＜0.001) increase in the risk of any CAD event .
Secondary outcomes were as follows: (1) concentration of ATP-binding membrane cassette transporter A1 (ABCA1), tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6); (2) the level of serum lipids; (3) the level of high sensitivity C-reactive protein (CRP); (4) the SAQ score; (5) scores of CM symptoms; (6) evaluation of the occurrence and composite of major adverse cardiac events (MACE). The SAQ was used to assess the patients’ quality of life from five aspects, i.e. the level of limitation of physical activity, steady-state angina pectoris, condition of angina pectoris attacks, satisfaction level of treatments, and cognition level of disease (DP). The scores of CM symptoms included the following aspects: chest pain, sense of suppression in the chest, attack inducement, and shortness of breath, fatigue, palpation, and spontaneous perspiration  (Table 3).
The first follow-up was carried out at 3 months after receiving treatment, and the patients’ health condition was assessed by inspecting medical records, which were acquired by completing the case report form. The second follow-up was undertaken at 6 months after receiving treatment, in which the eligible participants underwent CCTA and laboratory examinations, and the researchers also needed to assess the participants’ physical conditions according to the SAQ scores and scores of TCM syndrome questionnaire. The third follow-up was performed at 12 months, the eligible participants had to complete SAQ and TCM syndrome questionnaire.
Adverse events (AEs)
All drugs may have side effects or allergic reactions, although no adverse reactions of SGR have been reported yet. Any discomforts or unexpected situations that happen during the experiment period were taken as AEs into account regardless of whether they are related to the study intervention or not. All the AEs were recorded in case report form in detail. Serious AEs, including death, life-threatening or severely or permanently disabling events, were immediately reported to the principal investigator. The ethics committee assessed whether an AE was related to the experimental drug or not.
To ensure strict adherence to the study protocol and familiarity with the trial administration process, an independent committee will be formed by the principal research members prior to the beginning of the study. Data management personnel of the committee should be qualified, effectively trained and familiar with the functions of data management. A designated person is responsible for the data management of this clinical trial. When the patients are recruited to the research project, the demographic and baseline characteristic data will be collected by researchers. A standard case report form was used to collect data. Before start of recording, data were de-identified. Clinical outcomes, the results of SAQ, TCM syndrome questionnaire, adverse events, and the reasons why participants drop out of the study will be recorded in detail on case report forms (CRFs). In order to decease errors, data of the CRFs will be entered by two researchers independently. They will check each other's input values and only the consistent data can they be stored in the database. Paper files were kept in a locked filing cabinet in the hospital. With respect to the electronic documents, the results of laboratory tests and CCTA were stored on a password-protected computer, and access was restricted only to the principal investigator.
Determination of the sample size
The calculation of sample size was undertaken based on the results of our pilot study. We hypothesized that the expected difference in the primary outcome (coronary artery calcification score) between the SGR group and placebo group was estimated to be 10%. Based on a statistical power of 90% and a two-sided test size of a level of 5%, a sample size of 82 eligible cases needed to be recruited in the case group and control group. As there was a dropout rate of 15% within 6 months, 190 participants were eventually recruited.
All data analysis will be conducted by qualified statisticians in a double-blind manner according to the intention-to-treat principle. The database will be built by EpiData 3.1 software. In this study, SPSS 22.0 software (IBM, Armonk, NY, USA) was used to perform statistical analysis. Continuous variables were expressed as mean ± standard deviation (SD) or median, and categorical variables were reported as numbers and percentages. Student’s t-test was used for making comparison between the two groups as well. Besides, one-way analysis of variance (ANOVA) was applied for making comparison between the groups. Pearson’s chi-squared test was applied to sets of categorical data to evaluate how likely it is that any observed difference between the sets arose by chance. P-value < 0.05 was considered statistically significant.