Efficacy and Safety of Zhenwu Decoction in the Treatment of Diabetic Nephropathy: A Systematic Review and Meta-Analysis

Objective To perform a systematic evaluation of the clinical efficacy and safety of Zhenwu decoction (ZWD) for the treatment of diabetic nephropathy (DN). Methods PubMed, the China National Knowledge Infrastructure (CNKI), the China Science and Technology Journal Database (VIP), the Chinese Biomedical Literature Database (CBM), and the WanFang databases were searched, and a systematic review and meta-analysis of randomized controlled trials (RCTs) were subsequently conducted to compare the efficacy and safety of ZWD combined with conventional Western medicine (CWM) to conventional therapy alone in the treatment of DN. The Cochrane Handbook for Systematic Reviews of Interventions and GRADE criteria were utilized to assess the quality of the included literature, and RevMan 5.3 software was used for statistical analysis. Results 13 randomized controlled trials were included, involving 1347 patients with diabetic nephropathy assigned into two subgroups according to the disease duration. The results revealed that compared with conventional therapy alone, ZWD combined with CWM treatment significantly improved the total effective rate (OR = 3.88, 95% CI = (2.87, 5.26), P < 0.00001). Furthermore, ZWD combination therapy also decreased fasting blood glucose (MD = −0.72, 95% CI = (−0.97, −0.48), P < 0.00001), BUN (MD = −1.92, 95% CI = (−3.19, −0.64), P = 0.003), 24-hour urine protein (MD = −0.48, 95% CI = (−0.57, −0.39), P < 0.00001), and serum creatinine levels (MD = −51.17, 95% CI = (−66.95, −35.39), P < 0.00001). However,there was no statistical significance in the effect of combination therapy on creatinine clearance (MD = −0.64, 95% CI = [−8.21,6.92], P = 0.87). However, there was no statistical significance in the effect of combination therapy oncreatinine clearance (MD =−0.64, 95% CI=[−8.21,6.92], P=0.87). Conclusion ZWD combined with CWM outperformed conventional Western medicine in DN treatment. However, further investigations via multicenter RCTs with rigorous designs and higher quality are still warranted.


Introduction
According to the World Health Organization (WHO), the incidence of diabetes in China reached 11.2% in 2017 (compared to 0.67% in 1980), with approximately 114 million individuals sufering from diabetes and accounting for 24% of the total number of patients [1]; this was higher than the global incidence of 8.4% [2]. Te International Diabetes Federation (IDF) estimates that there could be 578 million people with diabetes worldwide (10.2%) by 2030 [3] and 783.2 million (12.2%) by 2045 [4]. Diabetic nephropathy (DN), one of the major complications of diabetes, is the leading cause of end-stage renal disease (ESRD). Based on the global prevalence of diabetes, the incidence of DN is increasing. Surveys indicate that approximately 40% of patients with type 2 diabetes mellitus (T2DM) are likely to develop DN [5].
Te predominant pathological characteristics of DN consist of glomerular sclerosis, tubulointerstitial fbrosis, and renal angiopathy. Its pathogenic factors and pathogenesis are complex and are principally related to glycolipid metabolism disorders, insulin resistance, hemodynamic fuctuations, oxidative stress, infammation, endoplasmic reticulum stress, autophagy, exosomes, and intestinal fora; however, the specifc mechanism remains to be further clarifed [6][7][8][9][10]. Clinically, proteinuria, renal function, and diabetes history are considered the main diagnostic indicators of DN. Presently, there is no specifc drug for treating DN, and management mainly includes controlling blood sugar and blood pressure, reducing proteinuria, and supporting symptomatic treatment [11], which fail to prevent disease progression. Terefore, the integration of traditional Chinese and Western medicine in the treatment of DN has garnered increasing attention.
Extensive investigation of the various pathological mechanisms of DN has revealed that the clinical efcacy of single-target therapy is suboptimal. Due to the limitations of applying such treatment, a higher proportion of studies are dedicated to investigating combination therapy. Unlike conventional Western medicine (CWM), traditional Chinese medicine (TCM) prescriptions combine a variety of medicinal materials in specifc proportions based on TCM's theoretical underpinnings. Tere are hundreds of potential chemical components exist in the formula. Some bioactive chemicals that can simultaneously act on several targets for treatment have been identifed. When combined, these active ingredients interact synergistically or antagonistically to modulate each other and yield a favorable therapeutic efect.
Records of TCM being used to treat DN in ancient China can be traced back to 2000 years ago. Based on its clinical manifestations, DN can be categorized as "xiaoke". With the concurrent occurrence of hypertension, proteinuria, edema, and other diseases, further classifcations such as "shenxiao," "edema," and "guange" can be associated with DN. Modern Chinese medicine also refers to DN as "xiaoke nephropathy". Zhenwu decoction (ZWD) is derived from the "Treatise on Febrile Diseases" (Shanghan Zabing Lun in China) by Zhang Zhongjing, which dates back to the Eastern Han Dynasty. It comprises fve herbs: Aconiti Lateralis Radix Praeparata, Poria, Atractylodis Macrocephalae Rhizoma, Paeoniae Radix Alba, and Zingiberis Rhizoma Recens (Table 1). Tese herbs have the combined efect of invigorating the spleen, tonifying the kidney, warming the yang, and alleviating water retention. ZWD is utilized to treat yang defciency arising from yang defciency in the spleen and kidney. Subsequent generations of physicians have conducted extensive research in this feld and have been attempting to treat DN on the basis of this prescription.
Due to its defnite therapeutic efect and scarce side efects, ZWD has been widely adopted in clinical settings. Despite an increasing number of clinical reports on combining ZWD and conventional western medicine for DN treatment, there is limited evidence of its efectiveness and safety. Terefore, a comprehensive and systematic evaluation of this combination drug is crucial. Tis study aims to provide theoretical and evidence-based medical support for the treatment of DN by conducting a meta-analysis to evaluate ZWD's efectiveness and safety.

Materials and Methods
Te review protocol was conducted under the guidance of PRISM and registered on International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY) with the registration number of INPLASY202290071.

Data Sources and Search Strategy.
To identify the clinical studies on ZWD combined with CWM for the treatment of DN, we searched fve databases from their inception to February 2022: PubMed, the China National Knowledge Infrastructure (CNKI), the China Science and Technology Journal Database (VIP), the Chinese Biomedical Literature Database (CBM), and the WanFang databases. Te following keywords were used: "Zhen Wu Decoction," "Zhen-Wu-Decoction," "Traditional Chinese medicine", "Chinese herb medicine," "Diabetic Nephropathy," "Diabetes Mellitus," "type 2 Diabetes Mellitus," "T2DM", "Diabetic Kidney Disease," "Kidney Diseases," or "randomized controlled trial," "Randomized," "clinical research," and "placebo". Te data were independently studied and collated by the two authors, and manual searches were conducted to track the necessary references and further improve the relevant information. Subsequent to this process, the target research articles were fnally confrmed. (1) Study type. Randomized controlled trials (RCTs) published in Chinese and English on ZWD for diabetic nephropathy.

Eligibility and Exclusion
(2) Type of participants. Adult patients who met the diagnostic criteria of DN.
(3) Intervention measures. Te control group was treated with CWM, including diabetes medication, hypoglycemic drugs, and hypotensive drugs. Te experimental group was administered either add-on ZWD in conjunction with the control group treatment or ZWD alone.

Exclusion
Criteria. Te exclusion criteria are as follows: (1) non-RCT; (2) no control group; (3) the experimental group adopt with other therapeutic methods, except for ZWD + CWM treatment or ZWD alone; (4) the control group was not treated with CWM; (5) nondiabetic nephropathy; (6) they did not meet the DN diagnostic criteria or did not clearly describe the diagnostic criteria; (7) the subjects sufered from severe primary diseases; (8) duplicated detection or published literature; (9) no target outcomes; (10) missing data and unable to contact the investigator.

Data Collection.
Te two system reviewers independently conducted extensive screening of the preliminary research articles potentially meeting the inclusion 2 Evidence-Based Complementary and Alternative Medicine criteria by examining titles and abstracts and eliminated nonconforming literature. Afterward, the two reviewers cross-checked the included documents and examined the full text to extract target data for classifcation and integration. If difering opinions arose, a third researcher (Rong Yu) was consulted. Te extracted data included the authors, publication year, baseline data (i.e., sample size, age, and duration), intervention measures, outcome indicators, and adverse events.

Quality Assessment.
Te methodological quality of the included RCTs was evaluated based on the assessment criteria outlined in the Cochrane Systematic Review Manual. Te quality criteria included the following: accuracy of the random allocation method; adequacy of allocation concealment; use of blinding methods; patients who were lost to follow-up or withdrew from the study; integrity of the outcome data; and other biases. GRADE prosoftware was utilized to assess the strength of the evidence to enhance the results' validity.

Statistical Analysis.
Te meta-analysis was performed using Review Manager 5.3.3 and Stata 12.0 software. We used the odds ratio (OR) to assess the binary variables. For continuous variables, the mean diference (MD, when results were in similar units of measure) or standardized mean diference (SMD, when results were in diferent units of measure) were employed to represent the diference between the groups. Te results were represented with a 95% confdence interval (CI). Te heterogeneity was evaluated using the chi-square test; if P > 0.1 or I 2 <50%, it was assumed that the heterogeneity was not evident and the fxed-efects model was selected; otherwise, the random efects model was validated. In addition, a sensitivity analysis was performed for each outcome to assess stability. We also completed the Egger test to detect potential publication bias.
Te detailed methodological quality evaluation is presented in Figures 2 and 3.

Sensitivity Analysis and Publication
Bias. An itemby-item elimination method was applied to investigate the included literature's data for a sensitivity analysis of the total efective rate, FBG, BUN, 24 h urine protein, creatinine clearance, and Scr. Tere were no signifcant changes in the stability of each study and the aggregated results of each efect size, except creatinine clearance, indicating the validity of the data analysis results. Furthermore, Egger's test was performed for each outcome to assess the potential publication bias. P < 0.05 was indicative of publication bias. Te analysis revealed the absence of publication bias for indicators other than the total efective rate (P = 0.032 < 0.05). Te creatinine clearance and the efective rate are depicted in Figure 10, and the entire summary is provided in Table 3. An extensive literature search revealed that all studies were conducted in China and that all reported results were favorable. Te publication bias may be related to the region, race, and unpublished negative results.

Discussion
In this study, ZWD signifcantly diminished fasting blood glucose, BUN, 24-hour urine protein, and serum creatinine levels; improved total efective rate, except for creatinine clearance(P＞0.05), with no noteworthy adverse efects. Tis demonstrates that ZWD is a safe and efective renoprotective therapeutic option. Moreover, it can be seen that in the future clinical treatment of DN, ZWD will be further popularized. Our fndings also augment confdence for an in-depth study of the mechanism of ZWD.
TCM is favored by numerous T2DM patients [25] and DN patients [26] by virtue of attributes such as a multi-target approach, low toxicity, and few side efects. Owing to its spleen-strengthening and yang-nourishing abilities, Zhenwu decoction has been a mainstay of Chinese clinical practice for thousands of years. According to modern pharmacological studies on its components, (1) ACPP-1, a polysaccharide derived from Aconitum coreanum (fuzi), markedly inhibits α-glycosidase and reduces the serum glucose level [27]. (2)    Heterogeneity: Tau   Evidence-Based Complementary and Alternative Medicine type 2 diabetic mice, improve glucose tolerance, enhance insulin sensitivity [28], and are endowed with diuretic and anti-infammatory properties [29,30]. (3) Pachymic acid (PA), an extractive derived from Poria, decreases serum creatinine and blood urea nitrogen and alleviates renal pathological damage in mice with acute kidney injury [31].

Evidence-Based Complementary and Alternative Medicine
Poria polysaccharide decreases 24 h urine protein and serum creatinine, averts kidney damage in type 2 diabetic rats, and impedes the development of diabetic nephropathy to a certain extent [32]. It also possesses antioxidant, anti-infammatory, and renoprotective attributes [33]. (4) Curcumin from Zingiberis Rhizoma Recens diminishes blood glucose, Scr, blood urea nitrogen, and urine albumen levels in DN rats. It regulates autophagy, attenuates epithelial-to-mesenchymal transition via the PI3k/Akt/mTOR pathway [34], and ameliorates DN in rats by alleviating renal infammation and oxidative stress [35]. In one clinical study, curcumin signifcantly lessened proteinuria in patients with DN [36]. (5) Paeoniforin regulates macrophages by inhibiting the iNOS expression and infammatory factor production, thereby mitigating clinical symptoms and diminishing the occurrence of DN in mice [37]. Previous studies demonstrated that paeoniforin alleviates damage to glomerular mesangial cells via the RAGE/mTOR autophagy pathway [38]. Its active ingredients reduce proinfammatory factor release through the endoplasmic reticulum stress pathway [39].
Contemporary studies have also demonstrated that ZWD can improve proteinuria and renal damage in rats with streptozotocin-induced diabetic nephropathy [40], alleviate cisplatin-induced acute kidney injury [41], protect against IgA nephropathy by regulating exosomes to inhibit the NF-kB/ NLRP3 pathway [42], and mitigate podocyte injury in rats with IgA nephropathy through the PPARc/NF-κB pathway [43]. Liu 2020 Meta-analysis estimates, given named study is omitted Lower CI Limit Estimate Upper CI Limit

(8 RCTS)
⊕⊕⊕Ο moderate ab * Te basis for the assumed risk (e.g., the median control group risk across studies) is provided in footnotes. Te corresponding risk (and its 95% confdence interval) is based on the assumed risk in the comparison group and the relative efect of the intervention (and its 95% CI). CI: confdence interval; OR: odds ratio; GRADE: working group grades of evidence. High quality: further research is very unlikely to change our confdence in the estimate of the efect. Moderate quality: further research is likely to have an important impact on our confdence in the estimate of the efect and may change the estimate.Low quality: further research is very likely to have an important impact on our confdence in the estimate of the efect and is likely to change the estimate. Very low quality: we are very uncertain about the estimate. Explanations: (a) no blinding. (b) High heterogeneity. (c) P < 0.05 in Egger's test.

Evidence-Based Complementary and Alternative Medicine
Te present study had several limitations. Firstly, the allocation concealment method was not defned in all of the included articles, and the accuracy of the collected clinical research data has yet to be verifed. Secondly, TCM treatment of diseases is "syndrome-"based, and syndrome differentiation is the fundamental guiding principle of TCM intervention. However, in clinical research, researchers usually apply a specifc drug to the treatment of DN, resulting in feeble or nonexistent syndrome diferentiation and treatment. Tirdly, the efcacy of DN intervention is principally refected in the longer time period following the intervention, making the evaluation of long-term efcacy particularly vital. However, follow-up observations of the long-term efcacy of patients in clinical studies are generally lacking and limited to the short-term time period following drug intervention. Finally, the dearth of multicenter and large-sample size prospective randomized controlled trials in clinical research diminishes the reliability and credibility of the experimental data. Terefore, more multicenter prospective studies with a large-sample size should be performed in subsequent clinical research.

Conclusion
In conclusion, compared with conventional Western medicine therapy, combination therapy can increase the total efective rate of DN patients and reduce fasting blood glucose, BUN, 24-hour urinary protein, and serum creatinine levels. Our results indicate that ZWD can impede the progression of DN by ameliorating glucose metabolism and renal function. Tis review provides a theoretical basis for the clinical application of ZWD combined with CWM in the treatment of DN. However, more high-quality multicenter RCTs would be required to validate the conclusions further and guide clinical practice.

Data Availability
Te data used to support the fndings of this study are available from the corresponding author upon request.

Conflicts of Interest
Te authors declare that they have no conficts of interest.