After screening patients based on inclusion and exclusion criteria and obtaining informed consent, eligible participants are enrolled in the study. The recruitment process continues until a minimum of 50 patients are reached.
To allocate participants to the two intervention (multi-drug probiotic) and control (placebo) groups, a block randomization method with four blocks is used to maintain a balance in the number of subjects in the two groups during the recruitment process.
The basic idea of block randomization is to divide patients into M blocks of size 2N, such that in each block N patients are assigned to A and N patients to B. The block is then randomly selected. This method ensures equal treatment allocation in each block provided that the block is fully used.
. The block size depends on the number of treatments, it should be short enough to avoid imbalance, and large enough to avoid guessing the treatment assignment in each group during the study. The block size should be at least 2 times the number of treatment nodes. The block size was not stated in the study so that the investigators were blinded to it. If the blocks were stated, the treatment series in each block could be guessed. For example, in a 2N=4 block, A A B should be B and in A A it can be inferred as B B. This can lead to selection bias. The solution to avoid this error is to: 1) not disclose the blocking mechanism 2) use random block sizes.
The randomization sequence is generated by an independent person who is not involved in the recruitment and evaluation of patients, using reliable randomization software (such as Random Allocation Software or the website randomization.com). The final sequence is stored in the form of a coded list.
Allocation Concealment:
To prevent bias, the randomization sequence is placed in opaque, light-tight, numbered, and sealed envelopes. Each envelope is opened only at the time of each patient's entry into the study and in numerical order. The person responsible for opening the envelope is a person who is not involved in the outcome assessment.
Allocation method:
After opening the envelope, the patient is allocated to one of two groups based on the code inside the envelope:
- Intervention group: at least 25 people receiving multi-faceted probiotics
- Control group: at least 25 people receiving placebo
Intervention standardization:
The probiotic and placebo are completely similar in shape, color, size, and packaging and are coded to maintain blinding of participants and clinical caregivers.
This study will be double-blind. Participants, clinical caregivers, outcome assessors, and data analysts will be unaware of the type of intervention (probiotic or placebo).
In the intervention group, patients will be treated with FamiLact capsules, and in the control group, patients will be treated with placebo capsules. The probiotic and placebo capsules are completely similar and indistinguishable in appearance, size, color, odor, packaging, and method of administration. The probiotic capsule is marketed by Zist Takhim Pharmaceutical Company [Iran] under the brand name FamiLact Capsule®, which was also used in this study. FamiLact® is a synbiotic formula (probiotic + prebiotic). This product contains high levels of safe and beneficial bacterial strains (Lactobacillus rhamnosus, Bifidobacterium lactis, Lactobacillus casei, Bifidobacterium bruchid, Lactobacillus acidophilus, Bifidobacterium longum, Lactobacillus plantarum, Bifidobacterium bifidum, Streptococcus thermophilus) along with fructooligosaccharide (FOS) as a prebiotic. In the intervention group, probiotic capsules were administered at a rate of one daily. In the control group, placebo capsules were used instead of Femi Lact capsules, which were completely identical in appearance to the original capsules and were in the form of a hard, two-part, white capsule. The ingredients in the Femi Lact capsules used are as follows: probiotic + prebiotic, and an inactive ingredient that included glycerin, distilled water, and titanium dioxide. Only similar inactive ingredients were used in the placebo capsules. The packaging and dosage form of the probiotic and placebo capsules were identical and indistinguishable, thus maintaining blinding.
Both products are packaged with identical codes, the only difference being the specific code used for blinding. The codes for each package (A and B) are assigned by an independent individual who is not involved in the data collection, evaluation, and analysis process and are stored in sealed envelopes. Researchers and patients will have no idea which code is for the probiotic and which is for the placebo.In the data analysis phase, the analysis is performed by a statistical consultant who is aware of the contents of the drug packages; therefore, the study was double-blind and the contents of the two drug groups are not known from the patient's entry into the study to the study and data collection.
Maintaining blinding throughout the study:
- The intervention and placebo packages are identical in appearance.
- The person responsible for distributing the packages is not involved in the outcome assessment.
- Participants will not be informed of their intervention type until the end of the study.
- Data analysis is also performed based on A and B codes and decoding is done only after the statistical analysis is completed.
In the event of a severe complication or a situation where treatment decision-making requires information about the type of intervention, the principal investigator may open the envelope related to that participant in coordination with the ethics committee. These cases will be recorded and reported.