Effect of traditional Chinese medicine on Graves’ disease: a network meta-analysis

Introduction: Graves’ disease (GD) is the most common cause of hyperthyroidism and can affect multiple systems of the body. Currently, commonly-used treatment methods for GD have a series of shortcomings. In contrast, traditional Chinese medicine has been proven to be effective in inhibiting the progression of GD and is expected to become a key direction for the development of new drugs in the future. Therefore, a network meta-analysis was performed to compare the impacts of different traditional Chinese medicines on the curative effect, thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), thyroglobulin antibody (TGAb), thyroid peroxidase antibody (TPOAb) and thyrotropin receptor antibody (TRAb) in patients with GD. Methods: PubMed, Embase, Cochrane Library, Web of Science, WanFang, Weipu, and CNKI were searched for the randomized controlled trials of traditional Chinese medicine on GD patients up to 19 December 2023. The quality of the included studies was evaluated regarding the risk of bias, and the data were analyzed by R software. Results: Thirty-five articles were included in the analysis, involving 2828 GD patients and traditional Chinese medicines including Bailing Capsule, Jinshuibao Capsule, Astragalus injection, Jiakangling Tablet, Jiakangling Capsule, Tripterygium Wilfordii, Sanjie Xiaoying Decoction, Prunella vulgaris (L.) Oral Liquid, P. vulgaris (L.) Granules, Xiehuo Xiaoying Recipe, Xiehuo Yangyin Powder, Yikang Pill and Yinjia Pellet. The results of network meta-analysis suggested that for GD patients, Bailing Capsule, Jiakangling Capsule, Tripterygium wilfordii, P. vulgaris (L.) Oral Liquid and Yinjia Pellet had better curative effect compared with Western medicine. Prunella vulgaris (L.) Granules and Yikang Pill could improve the TSH level. Prunella vulgaris (L.) Granules, P. vulgaris (L.) Oral Liquid and Yikang Pill could reduce FT3 level. Jiakangling Capsule, P. vulgaris (L.) Granules, P. vulgaris (L.) Oral Liquid and Yikang Pill could reduce the FT4 level. Prunella vulgaris (L.) Oral Liquid can reduce the level of TPOAb and TRAb. Besides, Yinjia Pellet was the most helpful in improving the curative effect. Yikang Pill could best improve TSH. Prunella vulgaris (L.) Granules had the best effect on reducing FT3. Prunella vulgaris (L.) Granules performed best in reducing FT4. Prunella vulgaris (L.) Oral Liquid had the most favorable effect on reducing TPOAb and TRAb. Conclusion: Based on the current research, it is safe to conclude that Chinese medicine can improve the curative effect and TSH level of patients with GD, and reduce the levels of FT3, FT4, TPOAb and TRAb. Besides, Yinjia Pellet is the most helpful in improving the curative effect. Yikang Pill can best improve TSH. Prunella vulgaris (L.) Granules have the best effect on reducing FT3. Prunella vulgaris (L.) Granules perform best in reducing FT4. Prunella vulgaris (L.) Oral Liquid has the most favorable effect on reducing TPOAb and TRAb. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#recordDetails, identifier CRD42024521912.


Introduction
Graves' disease (GD) is an autoimmune thyroid disease, which develops under the influence of immune, genetic, or environmental factors, so that too much thyroid hormone is synthesized and released into the blood, leading to the hyperactivity of digestive, circulatory, and nervous systems.The common symptoms of GD are heat intolerance, excessive sweating, emaciation, emotional lability, and diffuse symmetric goiter.Additionally, most patients have shown exophthalmos condition, which can lead to thyroid complications, hence a life-threatening situation.Graves' disease development and progression is influenced by heredity, immunity, oxidative stress and inflammatory infiltrate (Antonelli et al., 2020).It affect age groups.According to epidemiological studies, individuals aged between 30 and 60 years are susceptible to GD, that predominantly occurs in women and is the primary cause of hyperthyroidism in iodine-rich areas (Antonelli et al., 2020).Currently, a global incidence of GD is increasing annually, especially in younger age groups.To that, it has become the third highrisk endocrine system disease after glucose metabolism disorder and osteoporosis.In addition, its most common extrathyroid complication is Graves' ophthalmopathy, which affects about 30% of patients in the late stage of GD (Bartalena and Tanda, 2022).It is believed that the level of thyrotropin receptor antibody (TRAb) in GD patients is increasing, and it will produce pro-inflammatory factors and glycosaminoglycans after combining with thyrotropin receptor (TSHR) in adipocytes and fibroblasts, leading to diplopia, exophthalmos, conjunctival congestion, and even blindness (Bahn, 2015).As influenced by many factors, GD will cause a lot of pressure on patients, and bring a heavy burden to the livelihood of a society.Prophylaxis can reduce its adverse effects on physical and psychological health that become a clinical concern, and more research is needed to resolve this problem.
Apparently, there are three main treatments for Graves' disease: drug therapy, radioactive iodine therapy and surgical treatment.Drug therapy is preferred in China, but it has a long treatment cycle and a high recurrence rate after drug withdrawal, it may be accompanied by adverse reactions such as allergic skin rash, liver injury and agranulocytosis (Sun et al., 2009;Rivkees and Mattison, 2009;Grzywa et al., 2009).Traditional Chinese medicine has long been used for the treatment of GD and has shown many potential advantages.Clinical practice has revealed that integrating traditional Chinese medicine and Western medicine can not only reduce side effects, but also relieve the clinical symptoms of patients, shorten the medication cycle and reduce the recurrence rate.However, there is no unified standard for the understanding of etiology and pathogenesis of GD in traditional Chinese medicine.The prescriptions and drugs used for treatment differs, while no systematic comparison on efficacy of these treatments in GD.The purpose of this study is to compare the effectiveness of different Chinese medicines in the auxiliary treatment of GD through network meta-analysis, so as to provide a scientific basis for the clinical treatment of GD.
Exclusion criteria were as follows: duplicates, animal experiments, case reports, conference abstracts, reviews, studies with inaccessible full texts, and studies involving participants with other organic diseases.

Data extraction
Two authors rigorously screened the literature based on predetermined inclusion and exclusion criteria.Any disagreements were resolved through discussion or by seeking a third party's opinion to reach a consensus.Information extracted from the included studies encompassed key details such as the first author, year of publication, country, sample size, sex, age, interventions, and outcome measures.

Quality assessment
According to Cochrane Handbook 5.4 for RCT risk of bias assessment, two researchers evaluated the quality of the included studies from seven aspects: random sequence generation, allocation concealment, blinding of patients and investigators, blinding of outcome evaluator, incomplete outcome data, selective reporting and other bias.Studies were rated as "low risk of bias", "uncertain risk of bias", or "high bias risk", accordingly.Any differences in the evaluation results will be handled by a discussion with a third-party researcher to reach a consensus.

Data analysis
We employed Bayesian network meta-analysis using a prior vague random effects model with the R 4.3.2software (R Foundation for Statistical Computing), and adopted Markov Chain Monte Carlo methods (Jansen et al., 2008) to obtain the best pooled estimate and probabilities of each treatment regimen.Continuous outcomes were presented as the posterior mean difference (MD) and its 95% confidence interval (CI).Binary outcomes were expressed by odds ratio (OR) and its 95% confidence interval (CI).The surface under the cumulative ranking curve (SUCRA) percentages were calculated to estimate the probability of each intervention being the most effective.Network plots and funnel plots were generated using STATASE -64.In the network plots, each node represented a medication, and the edges represented the available comparisons.The size of each node was proportional to the number of patients included.Cumulative probability plots were created using the ggplot2 package.

Basic characteristics and risk of bias assessment of the literature
In these 35 articles, there were 2828 GD patients and traditional Chinese medicines including Bailing Capsule, Jinshuibao Capsule, Astragalus injection, Jiakangling Tablet, Jiakangling Capsule, Tripterygium Wilfordii, Sanjie Xiaoying Decoction, P. vulgaris (L.) Oral Liquid, P. vulgaris (L.) Granules, Xiehuo Xiaoying Recipe, Xiehuo Yangyin Powder, Yikang Pill and Yinjia Pellet in different doses (Table 1).All included studies explicitly described their blinding methods.The main risk of bias arose from deviations from the intended interventions, as assessed in the risk of bias summary (Figures 2, 3).

Heterogeneity test
We tested the heterogeneity for curative effect, TSH, FT3, FT4, TGAb, TPOAb and TRAb.The results showed that in the heterogeneity test of the curative effect, the I 2 was 17.9% in the pairwise comparison of Western medicine and Bailing Capsule (Supplementary Figures S1, S2 in Supplementary Material S1).In the heterogeneity test of TSH, the I 2 was 7.9% and 99.1% in the pairwise comparison of Western medicine and Bailing capsule, and of Yikang Pill and Western medicine (Supplementary Figures S3, S4 in Supplementary Material S1).In the heterogeneity test of FT3, the I 2 was 89.7%, 98.3%, and 97.7%, respectively in the pairwise comparison of Western medicine and Bailing Capsule, of Western medicine and Jiakangling Tablet, and of Yikang Pill and Western medicine (Supplementary Figures S5, S6 in Supplementary Material S1).In the heterogeneity test of FT4, the I 2 was 94.7%, 62.7%, and 94.0%, respectively in the pairwise comparison of Western medicine and Bailing Capsule, of Western medicine and Jiakangling Tablet, and of Yikang Pill and Western medicine (Supplementary Figures S7, S8 in Supplementary Material S1).In the heterogeneity test of TGAb, the I 2 was 100% in the pairwise comparison of P. vulgaris (L.) Oral Liquid and Western medicine, and of Yikang Pill and Western medicine (Supplementary Figures Frontiers in Pharmacology frontiersin.org07 S9, S10 in Supplementary Material S1).In the heterogeneity test of TPOAb, the I 2 was 98.4%, 97.6%, and 93.5%, respectively in the pairwise comparison of Western medicine and Bailing Capsule, of P. vulgaris (L.) Oral Liquid and Western medicine, and of Yikang Pill and Western medicine (Supplementary Figures S11, S12 in Supplementary Material S1).In the heterogeneity test of TRAb, the I 2 was 99.9%, 99.8%, 0.0%, and 99.3%, respectively in the pairwise comparison of Western medicine and Bailing Capsule, of Western medicine and Sanjie Xiaoying Decoction, of Xiehuo Xiaoying Recipe and Western medicine, and of P. vulgaris (L.) Oral Liquid and Western medicine (Supplementary Figures S13, S14 in Supplementary Material S1).

Publication bias assessment
We used a funnel plot to evaluate the publication bias of efficacy, TSH, FT3, FT4, TGAb, TPOAb and TRAb, and the results indicated that there was a greater possibility of publication bias in these indicators (Supplementary Figures S15, S21 in Supplementary Material S1).

Discussion
Graves' disease, as an autoimmune disease, has extensive influences, and can negatively affect multiple organs.Due to poor nutrition and increased life pressure, the number of patients with this disease is also increasing each year.However, there has been no great progress in the treatment methods, which are mainly drugs, radioactive iodine ( 131 I) therapy and surgery.All carry a risk of adverse reactions.Alternatively, traditional Chinese medicine has a significant effect in the adjuvant treatment of GD, and can markedly reduce symptom remission rate and course of treatment, which effectively makes up for the limitations brought by Western medicine.However, there is no systematic research on this aspect at present, so this network meta-analysis compared different traditional Chinese medicines on the curative effect, and levels of TSH, FT3, FT4, TGAb, TPOAb and TRAb in GD patients, which is also the highlight of our study.
This study has found that Yinjia Pellet ranks first in improving curative effect, followed by Common Threewingnut Root.Yikang Pill has the best effect on raising TSH level, followed by P. vulgaris (L.) Granules.In improving FT3 level, P. vulgaris (L.) Granules has the best effect, followed by Jiakangling Capsule.The effect of P. vulgaris (L.) Granules on improving FT4 level is the most significant, followed by Jiakangling Capsule.Prunella vulgaris (L.) Oral Liquid has the best effect on reducing TGAb level, followed by Yikang Pill.As to TPOAb level, P. vulgaris (L.) Oral Liquid has the best effect, followed by P. vulgaris (L.) Granules.In improving the level of TRAb, P. vulgaris (L.) Oral Liquid is the first choice, followed by Sanjie Xiaoying Decoction.Modern pharmacological research shows that the main components of Yinjia Pellet, such as Honeysuckle Flower, Rhizoma Coptidis and P. vulgaris (L.), can boost the phagocytosis of white blood cells and inflammatory cells and reduce tumor necrosis factor alpha (TNF-α).Thereby, it can reverse the inflammatory changes of tissues, reduce the toxic effect of natural killer cells, regulate the immune system, reduce the secretion and synthesis of thyroid hormones, and distinctly relieve the symptoms of patients such as anxiety and overeating (Myśliwiec et al., 1999;Jeong et al., 2023;Liu et al., 2022).Tripterygium Wilfordii has anti-inflammatory, anti-allergic and immunosuppressive effects.It can significantly reduce the levels Risk of bias summary.
Frontiers in Pharmacology frontiersin.org08 of TNF-α and interleukin-2, inhibit the activation of T cells, regulate cellular immunity and humoral immunity, restore the balance of Th1/Th2 cells and relieve clinical symptoms (Liu et al., 2019).Yikang Pill can reduce the sensitivity of target cells to thyroxine, inhibit lymphocyte infiltration and fibrous tissue proliferation of the thyroid, reduce the damage of thyroid epithelial cells, accelerate the degradation of triiodothyronine in vivo, restore the function of the thyroid, and have a benign regulatory effect on the abnormal     immune response of thyroid (Shuguang et al., 2010;Kokkinos et al., 2007).In addition, a high dose of thyroid hormone will increase the decomposition of protein and fat, further leading to abnormal secretion of adipocytokines such as adiponectin, serum-free fatty acids and leptin, which will affect glucose and lipid metabolism.
Yikang Pill can reduce adiponectin and serum-free fatty acids, regulate leptin secretion, reduce thyroid hormone levels, and improve TSH levels through the feedback mechanism (Pontikides and Krassas, 2007;Biondi, 2010).Both P. vulgaris (L.) Granules and P. vulgaris (L.) Oral Liquid are P. vulgaris (L.) extracts, but their onset time and therapeutic effect are different because of different preparations (Mengqiu et al., 2020).At present, some meta-analyses have proved that P. vulgaris (L.) preparations combined with Western medicine can effectively improve thyroid function and reduce autoantibodies (Gao and Li, 2023).Prunella vulgaris (L.) polysaccharide is one of the main components of P. vulgaris (L.), which can affect the synthesis and secretion of thyroid hormone.This effect may be achieved by inhibiting the activation of the ERK pathway.Prunella vulgaris (L.) polysaccharide can affect the activation of the Raf system, delay the phosphorylation of serine residues in MEK, and thus affect the activation of its substrate ERK1/ 2, so as to reduce cell proliferation and differentiation (Campbell, 2014;Waseem et al., 2014;Ko et al., 2013).It has been found that P. vulgaris (L.) can regulate the function of peripheral lymphocytes, prevent the destruction of follicular cells and further repair damaged follicular cells, so that thyroid function and antibodies can return to normal (Huilin et al., 2020).Some studies have also revealed that P. vulgaris (L.) has a significant effect on specific immunity, which can interfere with the Th1/Th2 ratio, downregulate TPOAb, reduce the production of thyroid hormone and regulate the immune state, thus promoting thyroid function (Guo et al., 2021).Jiakangling Capsule can target the transduction pathway of Akt signaling, regulate cell proliferation and apoptosis, inhibit the overphosphorylation of mTOP to some extent, affect the transcription activation of proliferation-associated genes by downstream signaling pathways, improve thyroid function and regulate immunity (Fingar and Blenis, 2004;Zhang et al., 2023;Li et al., 2015).Other studies have shown that Jiakangling Capsule can coordinate with HPT axis, play a positive role in regulating TSH, and reduce the synthesis and secretion of thyroid hormone through feedback mechanism, so as to improve the thyroid function of patients (Yan, 2022).Sanjie Xiaoying Decoction has an obvious effect on reducing TRAb, which can alleviate the stimulation to thyroid cells and downregulate HPT axis through feedback, improve thyroid function and reduce the recurrence rate (Zhongyu, 2020).

Limitations
In this study, we discussed the disparities of different traditional Chinese medicines in the adjuvant treatment of Graves' disease, but we found that there were no significant differences among these top intervention measures in the league table.Hence, more research is warranted to validate our view on the option of traditional Chinese medicines.

Frontiers in Pharmacology
frontiersin.org There are still some limitations in this study.Firstly, the literature quality is low, and most of the included studies are not registered, of which the task concealment and blinding method were not described.This limits the reliability of the results.Secondly, the included original research is subjective in the evaluation of clinical efficacy, and there may be publication bias and implementation bias.Thirdly, the included studies are all in Chinese, which reduces the extrapolation capability of the results.Fourthly, different dosage forms of traditional Chinese medicine are not uniform, so there may be errors in the research conclusions.Fifthly, most of the studies fail to include the follow-up to patients and pay little attention to the long-term efficacy of drugs.Sixth, the sample sizes of studies on different traditional Chinese medicines included in this analysis are different.Therefore, in order to draw more accurate conclusions, more high-quality randomized controlled trials are needed.

Conclusion
Based on the current research, it is safe to conclude that traditional Chinese medicine can improve the curative effect and TSH level of patients with Graves' disease, and reduce the levels of FT3, FT4, TPOAb and TRAb.Besides, Yinjia Pellet is the most helpful in improving the curative effect.Yikang Pill can best improve TSH.Prunella vulgaris (L.) Granules have the best effect on reducing FT3.Prunella vulgaris (L.) Granules perform best in reducing FT4.Prunella vulgaris (L.) Oral Liquid has the most favorable effect on reducing TPOAb and TRAb.Therefore, in future clinical and scientific research practices, Yinjia Pellet, P. vulgaris (L.) Granules, and P. vulgaris (L.) Oral Liquid can be further investigated, thus promoting the development of new drugs.

FIGURE 1
FIGURE 1Literature retrieval flow chart.

FIGURE 2
FIGURE 2Risk of bias graph.

FIGURE 4
FIGURE 4Meta analysis of therapeutic effect ((A): Network plot, (B) Area under the cumulative probability curve, (C) forest plot).

FIGURE 5
FIGURE 5 Meta analysis of TSH ((A): Network plot, (B) Area under the cumulative probability curve, (C) forest plot).

TABLE 1
Characteristics of the included studies.

TABLE 1 (
Continued) Characteristics of the included studies.

TABLE 2
Comprehensive ranking of SUCRA.