Lei Zhang , Zhi-Juan Wu, Jian-Wei Zhang

1. The First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan 250014, China

2. Reproductive and Genetic Center of Integrated Traditional Chinese and Western Medicine, the Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan 250011, China

Keywords:Chinese herbal compound prescription Kidney deficiency syndrome Infertility Clinical curative effect Meta-analysis

1. Introduction

According to the data of the World Health Organization (WHO),infertility and sterility will be the third most serious disease in the 21st century after cancer and cardiovascular diseases. 15%-20% of women of childbearing age in China suffer from infertility[1], and the trend has been gradually increasing in recent years.[2] In China, many infertility patients seek the help of traditional Chinese medicine. With the wide application of Traditional Chinese medicine, its advantages and characteristics are becoming more and more prominent. In this paper, guided by evidence-based medicine,the effect of Chinese herbal formula on the clinical efficacy of infertility patients with kidney deficiency syndrome was discussed and evaluated objectively, to provide a reliable basis for clinical practice.

2. Data and methods

2.1 Literature Sources

Search CNKI, VIP, Wanfang, PubMed, EMBASE, Ovid; Chinese database search terms: 1) "infertility" (2) " Traditional Chinese medicine " OR " formula " OR " recipe (3) "Kidney deficiency" OR" kidney qi deficiency " OR " kidney yang deficiency " OR " kidney yin deficiency "; English retrieval, take PubMed as an example:((((Kidney deficiency[Title/Abstract]) OR shen deficiency[Title/Abstract]) OR kidney qi deficiency[Title/Abstract]) OR kidney yang deficiency[Title/Abstract]) OR kidney yin deficiency[Title/Abstract])AND (Infertility) AND ((((Traditional Chinese medicine [Title/Abstract]) OR formula[Title/Abstract]) OR recipe[Title/Abstract]).Retrieval date Self-built database to July 31, 2021.

2.2 Literature inclusion criteria

Patients: Infertility with clear TCM syndrome differentiation criteria and Western diagnostic criteria. Intervention: The experimental group is treated with TCM compound or TCM compound combined with Western medicine, and the control group is treated with Western medicine. Type of study: Clinical randomized controlled trials in Chinese and English languages, regardless of whether blindness was used. The report contains necessary efficacy evaluation indicators and results, such as clinical pregnancy rate, clinical total effective rate, TCM syndrome score, etc.

2.3 Literature exclusion

Criteria non-randomized controlled trials; Animal experiments;Case report experience summary; Research progress report and review; The experimental group combined with external treatment of traditional Chinese medicine, such as acupoint sticking acupuncture moxibustion; Full text or experimental data were not available.

2.4 Literature information extraction and Quality Evaluation

The literature information was extracted independently by 2 graduate students to establish the Excel2019 database, which mainly included the information of the subject investigator's study time, sample size, treatment measures, observation outcome index withdrawal and loss of follow-up. Two evaluators independently evaluated the quality of the included literature according to the Quality evaluation criteria of the Cochrane Manual (random sequence generated the distribution of data integrity and selective reporting of hidden blind results and other biases), and a third expert was invited to discuss and resolve differences of opinion.

2.5 Statistical processing

Rev Man5.2 software was used for data synthesis and metaanalysis. Odds Ratio (OR) was used for dichotomous variables, and mean difference (MD) or standardized mean was used for continuous variables Difference,SMD), both were expressed with 95%CI. Chisquare test was used to test the heterogeneity of literature. If I2＜50%, using fixed effect model, if I2＞50% , the factors that may lead to heterogeneity were analyzed, and the random effect model was used for meta-analysis. GRADE Profiler 3.6 software was used to evaluate the quality of evidence for the main outcome indicators. It was divided into four grades of high quality, Moderate quality, Low quality and Very low quality.

3. Results

3.1 Literature retrieval Results

A total of 2371 literatures were retrieved by searching Chinese and English databases, 501 literatures that were repeatedly published were excluded, title and abstract were read one by one, and those literatures that absolutely did not meet the inclusion criteria were excluded. The remaining 157 literatures were read in full. A total of 32 literatures with incomplete data and repeated publication were included in this meta-analysis. See Figure 1 for literature screening process and results.

Figure 1 Literature screening process

3.2 Basic Features included

32 studies were included [3-34], including 1427 patients in the experimental group and 1288 patients in the control group. All the experimental groups were treated with TCM compound or TCM compound combined with Western medicine, while the control group was treated with western medicine. As shown in table 1, most of the studies gave the average age of the subjects, and only 5 studies[3,10,23,25,29] gave the age range.

Table 1 Basic information of the included literature

3.3 Quality evaluation of the included literature

Thirty-two studies [3-34] were independently assessed by two investigators in the Cochrane Manual for risk of bias. Randomized method evaluation: all included studies were RCT experiments,17 studies [4,5,12-14,16,17,19-21,26-28,31-34] used the random number table,2 studies [10,22] used the lottery method,1 study [9] used the block randomization method, the remaining 12 [3,6-8,11,15, 18,23-25,29,30] the random method was not mentioned, so the risk of bias was unknown. Only 2 studies [9,21] used envelopes for allocation hiding. Blind evaluation: only 1 study [26] conducted single blindness on subjects. For follow-up evaluation: 15 studies [6,10-13,15,16,18,21-27] were followed for 3 months to 1 year for pregnancy and abortion.Evaluation of loss to follow-up and shedding: 5 studies [4,14,19,26,28]had cases of loss to follow-up and shedding due to personal factors or adverse reactions. Regarding safety reports: five studies [16,23,30-32] documented gastrointestinal reactions, abnormal uterine bleeding,and OHSS adverse events. Therefore, there are many sources of bias in the literature included in this study and the risk of bias is high, as shown in Figure 2.

Figure 2 Risk bias assessment diagram of included studies

3.4 Main indicators

3.4.1 Clinical pregnancy rate

Twenty-nine studies [4-24,26-31,33,34] reported clinical pregnancy rate outcome measures, as shown in Figure 3. The included literature was homogenous(Chi2 = 21.00, P = 0.83, I2 = 0%),and the fixed-effect model was used. The results showed that the clinical pregnancy rate in the experimental group was significantly increased, and the difference was statistically significant [n=29,OR(95%CI)=2.47(2.07, 2.96), P＜0.00001].

Because the number of included studies is sufficient, funnel plot analysis can be done. The funnel plot shows an asymmetric trend,indicating the possibility of publication bias, as shown in Figure 4.

Figure 3 Forest plot of clinical pregnancy rate

Figure 4 Funnel plot of clinical pregnancy rate

3.4.2 Total efficiency rate

Twenty studies [3-5,8,11,12,14-17,19,21,22,24-27,30,32,34] reported total clinical response rates in the included literature, as shown in Figure 5. The homogeneity of the study was high (Chi2 = 15.21, P = 0.71,I2 = 0%), and the results showed that the experimental group was better than the control group in improving clinical efficacy, with statistical significance[n=20, OR(95%CI)=3.77(2.83, 5.03), P＜0.00001].

Figure 5 Total efficient forest map

3.4.3 TCM syndrome integral

Fourteen studies [6,9,11,17-24,26,27,30] reported TCM syndrome integral results, as shown in Figure 6. Heterogeneity was observed in the included studies(Chi2 = 113.02, P ＜0.00001, I2 = 88%),and a random-effects model was used for meta-analysis. The results showed that there was significant improvement in the experimental group with the decrease of TCM syndrome score, and the difference was statistically significant[n=14, MD(95%CI)=4.34(3.08,5.61), P＜0.00001].

Figure 6 Forest plot of TCM syndrome integration

3.4.4 Ovulation rate

Ovulation rates were reported in 20 studies [4,5,7,10-14,16-19,21,22,24,25,27-29,31], as shown in Figure 7. The included studies had good homogeneity(Chi2 = 44.01, P =0.0009, I2 = 57%), and a fixed-effect model was used for meta-analysis. The results showed that the cycle ovulation rate after Chinese medicine treatment was better than the control group, and the difference was statistically significant[n=20, OR(95%CI)=2.21(1.85,2.63), P＜0.00001].

Figure 7 Ovulation rate forest map

3.4.5 BBT bidirectional occurrence rate

Eleven studies [9,11,14,17,18,20-22,24,27,29] reported the prevalence of bidirectional BBT, as shown in Figure 8. The heterogeneity of the included studies was low (Chi2 = 17.86, P=0.06, I2 = 44%), and a fixed-effect model was used for meta-analysis. The results showed that the occurrence rate of BBT bidirectional type in experimental group was higher than that in control group, and the difference was statistically significant[n=11, OR(95%CI)=2.65(2.02,3.48), P＜0.00001].

Figure 8 Forest diagram of bidirectional BBT occurrence rate

3.5 Evidence quality GRADE Evaluation

The five main outcome indicators were evaluated for evidence quality GRADE. The clinical pregnancy rate, total effective rate,,total response rate, BBT bidirectional occurrence rate was of low quality GRADE, and the TCM syndrome integral ovulation rate was of very low quality GRADE, as shown in Table 2.

Table 2 GRADE evidence evaluation

4. Discussion

Under the guidance of kidney-dominated reproduction theory, there are many randomized controlled clinical experiments on infertility of kidney-yin deficiency syndrome and kidney-Yang deficiency syndrome. Due to the complexity of syndrome differentiation,this part of syndrome type can be classified as kidney deficiency syndrome. Meta-analysis of the clinical efficacy of Chinese herbal compound on infertility with kidney deficiency syndrome is still blank. Therefore, a total of 32 literatures were included in this study based on infertility of kidney deficiency syndrome. According to the results of Meta-analysis, the treatment with TCM compound or TCM combined with Western medicine can effectively improve the occurrence rate of BBT bidirectional type and ovulation rate,improve TCM syndrome score, and improve clinical pregnancy rate and total effective rate.

All Chinese medicines are formulated under kidney tonifying legislation. The timing of TCM application was slightly different in the 32 studies, which could be roughly divided into three situations: Adjust medication according to menstrual cycle stage;Using traditional Chinese medicine for ovulation promotion during menstruation; Traditional Chinese medicine should be used only in follicular phase. Most Chinese medicine prescriptions are selfdesigned or experiential, such as Bushen Cupai Decoction ,Bushen Yulin Decoction, BushenZhuyun Decoction, ZHU’s Tiaojing Cuyun Recipe, and so on. Chinese medicine dosage form has granule or decoction. One study [13] observed the clinical efficacy of "425 prescriptions " in Liu Fengwu's Experience in Gynecology. Other self-designed prescriptions have different names but similar drug composition, such as dang gui, shu dihuang, tu sizi,gou qizi, niu xi,and lu jiaojiao. The traditional Chinese medicine has the effect of tonifying kidney, replenishing qi and nourishing blood. Secondly,the legislation of the prescription conforms to the particularity of the menstrual cycle, according to the special periodicity of women,menstrual period by late menstrual period intermenstrual period. The rise and fall of qi and blood Yin and Yang vary in different stages,so that qi and blood are sufficient to get pregnant and become a fetus. The four-stage cycle adjustment method is more suitable for patients with regular menstrual cycle. Other scholars [21,23] use drugs by stages in the early and late stages, warming and tonifying kidney Yang in the early stage and nourishing kidney and Yin in the late stage.

This study has the following deficiencies and limitations: Objective evaluation indexes of infertility before and after TCM treatment were evaluated. TCM syndrome score was mentioned in many studies, but there was no clear grading quantitative standard and no integral calculation formula, so there was great heterogeneity among different studies. BBT body temperature sheet was recorded in this study, but there was no unified quality control standard for basic body temperature measurement method, so the evaluation was subjective. Due to the risk of bias and heterogeneity, the internal authenticity of research results is affected and the GRADE evidence is reduced, which provides a certain reference for clinical decisionmaking. In the future, it is also hoped that there will be more largescale randomized controlled double-blind experiments in more centers to provide higher-grade evidence-based medical evidence for the clinical efficacy evaluation of Traditional Chinese medicine.

Author’s contribution The first author, Zhang Lei, is responsible for the conception and writing of the paper; the second author, Wu Zhijuan, is responsible for literature screening and data extraction; Zhang Lei is responsible for data analysis; the corresponding author, Zhang Jianwei, is responsible for checking data and reviewing the paper.