Combining fire needle plus cupping with famciclovir and gabapentin in the treatment of acute herpes zoster: a revised intervention approach

Abstract

This study aimed to investigate the efficacy and safety of fire needle plus cupping (FC) combined with oral famciclovir and gabapentin for the treatment of acute-phase herpes zoster (AHZ). This study was conducted as a superiority, randomized controlled trial in which 84 patients with AHZ who met the diagnostic criteria were selected and randomly assigned to three groups on a 1:1 basis. Group A: received oral famciclovir with gabapentin treatment (FG); Group B: received fire needle plus cupping (FC) with FG. The primary outcome was the difference in patients' pain levels as assessed by the VAS scale. Secondary outcomes were changes in sign-symptom scores, incidence of adverse effects, and incidence of PHN. After one week of treatment, both groups showed decreased VAS scores and symptom-sign scores compared to baseline. However, the decrease in VAS scores was significantly higher in Group B compared to Group A (p < 0.0001). Similarly, the improvement in symptom-sign scores was significantly better in Group B (p < 0.0001). Group A experienced a higher rate of adverse reactions (21.95%) compared to Group B (4.76%), with a significant difference between the groups (p = 0.021). Furthermore, the incidence of PHN was significantly lower in Group B (4.76%) compared to Group A (29.27%) (p = 0.003). Fire needle therapy combined with medication demonstrated superior analgesic effects, improved symptom relief, and reduced adverse reactions and the incidence of PHN compared to medication alone in the treatment of AHZ. Importantly, the fire needle and cupping therapy should be considered an add-on therapy to standard drug treatment, rather than a standalone treatment. Additionally, due to the lack of a sham-treated control group, the placebo effect associated with invasive therapies such as fire needling and cupping. Future studies should include a sham control group to better isolate the true effects of the treatment.

Clinical trial registration: This study was registered with the Chinese Clinical Trial Registry under the code ChiCTR1800015372 (https://www.chictr.org.cn). Registered on 28 March 2018. All experiments on the participants were following the Declaration of Helsinki.

Introduction

Herpes zoster (HZ) is an acute infectious skin disease caused by latent varicella zoster virus (VZV), particularly in immunocompromised individuals, and its incidence has been on the rise [1–3]. While HZ can affect individuals of any age, its prevalence is notably higher among those aged 50 and above [4]. Persistent neuropathic pain and cluster-like blisters constitute its primary symptoms, which not only severely impacts the quality of life of patients, but may also lead to insomnia, anxiety and even depression and suicide. Additionally, HZ increases the risk of cerebrovascular events, autoimmune diseases, atrial fibrillation and postherpetic neuralgia (PHN), particularly in severe cases [5–8].

Treatment goals for acute herpes zoster (AHZ) focus on rapid pain relief, improvement in quality of life, nerve repair, and reduction of sequelae incidence [9]. Pharmacological interventions typically involve antiviral, analgesic, and neurotropic medications, sometimes supplemented with glucocorticoids in specific cases. However, these treatments often come with varying degrees of adverse reactions and efficacy levels, posing challenges in patient satisfaction and management [10]. In addition, the HZ vaccine is commonly used for prevention of the disease, but its effectiveness decreases with age and its application is limited by the population. It has been reported that patients taking immunosuppressants may reactivate the latent HZ virus and increase the risk of HZ [11]. At the same time, the high cost of vaccination and secondary vaccination have also become another barrier to its popularization [12]. Considering the limitations and risks of drugs, there is still an urgent clinical need to provide relatively faster and more effective alternative treatment options.

In traditional Chinese medicine clinics, acupuncture is often used as a non-pharmacological intervention for HZ, with favorable results. Its worldwide recognition is due to its efficacy in modulating pain and inflammation through multiple mechanisms [13–16]. Acupuncture was recommended as the treatment method for HZ in the 2018 Chinese Consensus of Herpes Zoster [17], and fire needle plus cupping are quite distinctive therapies in acupuncture. Fire needle is a method in which the tip of a needle is burnt red and then quickly inserted into a selected area or acupuncture point, and then quickly withdrawn. Practitioners of Chinese medicine believe that fire needle can transmit the heat energy of fire into acupoints, thus achieving the purpose of activating blood circulation, warming the meridians and relieving pain. From a modern medical perspective, fire needle can improve inflammation and regulate the immunity and central function of the body [18, 19]. Immediately after the fire needle operation, cupping is performed. This combination therapy is used extensively since it promotes qi and activates blood circulation, which then in turn could increase the nutrition around the lesion and promotes tissue regeneration, and resulting in natural wound healing [20]. The effectiveness of FC therapy in the treatment of AHZ has been confirmed in recent Chinese studies [21–23], however, these studies were not conducted under rigorous randomized controlled trials and lacked sufficient sample size and multiple perspectives for comparison, thus lacking sufficient data to prove the effectiveness of FC therapy, resulting in the effectiveness and safety of the combination therapy still not being recognized internationally. Therefore, we conducted a rigorous randomized clinical controlled trial aiming to provide evidence to assess the effectiveness and safety of FC for AHZ, as well as to explore whether the antiviral drug, acyclovir, has a facilitating effect on FC.

Methods

Design and settings

This study was designed as a superiority randomized controlled trial to compare the effectiveness of famciclovir plus gabapentin (FG) with famciclovir plus gabapentin combined with fire needle and cupping therapy (FC + FG). However, it is important to clarify that the FC + FG treatment should be considered an add-on therapy to the standard drug treatment, rather than a standalone treatment to be directly compared with FG. Given the invasive nature of fire needle and cupping, these therapies are associated with a strong placebo effect, similar to other invasive procedures.

In this study, a sham-treated control group (i.e., sham fire needle and cupping) was not included. This limitation stems from ethical concerns and practical challenges associated with creating a convincing sham fire needle procedure, which would require skin penetration without therapeutic intent. Additionally, there were concerns that sham treatments could negatively affect patient trust and compliance. While this study does not allow for a precise quantification of the placebo effect, existing literature suggests that placebo effects in invasive therapies like fire needling and cupping may range from 30 to 60% [24, 25]. Therefore, the results presented should be interpreted as the combined effect of active treatment and placebo effects, and future studies should consider incorporating sham control groups to better isolate these effects.

The study design did not involve any patients or their families at the initial design stage. Recruitment of subjects was conducted at the Sixth Affiliated Hospital of Kunming Medical University between November 1, 2018, and March 1, 2020. Eligibility criteria were assessed by the researchers, who provided subjects with comprehensive information about the study objectives, procedures, potential benefits, risks, and the right to withdraw consent at any time. Informed consent was obtained from all subjects. The study protocol was successfully published (10.1186/s13063-020-04599-2) and approved by the Ethics Committee of the Sixth Affiliated Hospital of Kunming Medical University (20,170,730–01) and has been registered with the Chinese Clinical Trials Registry (http://www.chictr.org.cn/. ChiCTR1800015372). Adherence to the tenets of the Declaration of Helsinki and the use of CONSORT 2010 reporting guidelines was ensured throughout the study [26].

Inclusion criteria

1. Age between 18 and 60 years old, regardless of gender; 2. Skin rash and clustered blister in asymmetrical skin area; 3. Precursor symptoms such as general discomfort and fatigue before rash; 4. Nerve pain in the affected area, skin hypersensitivity; 5. Rash distributed along the innervation area; 6. Unilateral, not exceeding the midline of the body; 7. Pain intensity as assessed by VAS (0–100 mm) of 50 mm ≤ pain intensity ≤ 80.

Exclusion criteria

1. Insulin-dependent diabetes mellitus or other diseases that affecting peripheral sensitivity (e.g., polyneuropathy, chronic pain syndrome); 2. Bleeding tendency (e.g., anticoagulant use, coagulation dysfunction, thrombocytopenia); 3. Pregnancy or lactation; 5. Surgery within the last 3 months; 4. Diseases affecting quality of life (e.g., cancer, paralysis);6. Mental illness (e.g., depression, schizophrenia, dementia) or severe heart/lung/kidney disease; 7. Exposure to fire needle, cupping, painkillers, or other complementary and alternative treatments for this disease prior to treatment; 8. Contraindications for famciclovir, gabapentin, fire needles, and cupping.

Randomization and allocation concealment

1. Block setting: 84 participants are numbered 1–84 according to the time of participation, the block length is 4, and 21 blocks are set; 2. Obtaining random numbers: start with any two-digit number in the random number table, and take 84 numbers to the right; 3. Grouping: 4 random numbers of each block are sorted from small to large, sorts 1 and 2 are Group A, sorts 3 and 4 are Group B; 4. Random Group Concealment: the grouping conditions of participants are packed into 84 envelopes, and all the envelopes are numbered in order and sealed. To ensure the randomization process, the serial number will be printed on the outside of the opaque envelope and the assignment of the group will be sealed on the inside of the envelope.

Blinding

Since treatment for fire needle plus cupping could not be performed blind, we will, instead, first conceal information related to randomized grouping and the results associated with the grouping of subjects, and then, we seek to provide sensory tests (outcome evaluators), data inspectors, and statistical analysts who are not aware of the detailed grouping and treatment of subjects as blind.

Sample size estimation

We will compare the difference in effectiveness of the two groups. Sample size estimation is based on the method of the Book of Health statistics[27], with type I error α = 0.05 and type II error β = 0.1, using the bilateral test. According to the literature, the cure rates of famciclovir and for fire needle plus cupping for HZ were 37.8% and 76.4%, respectively. It was speculated that the cure rate of famciclovir plus fire needle plus cupping was 80.0%, which was substituted into the formula:

$$n=\frac{2\lambda }{{(2{\text{sin}}^{-1}\sqrt{p_{\mathit{max}}}-2{\text{sin}}^{-1}\sqrt{p_{\mathit{min}}})}^2}$$

where Pmax = 0.80 and Pmin = 0.378. The calculated result was a sample size of 32 subjects per group. Therefore, the number of samples required for the study was 64. This study required a minimum of 70 samples, allowing for a drop-out rate of 9–10%. A total of 84 subjects were enrolled in this study.

Interventions

All subjects underwent a 1-week trial. Patients are prohibited from using other analgesic drugs or therapies. Fire needle plus cupping are operated by acupuncturists who have obtained a master's degree in acupuncture and are trained in fire needle plus cupping with years of clinical experience.

Group A: Patients in Group A are treated with famciclovir plus gabapentin (FG).

The dosage of famciclovir hydrochloride is 0.25 g/time, 3 times a day according to the manufacturer's recommendation (Livzon Pharmaceutical Factory). The single dose of gabapentin is 900–3600 mg per day. According to the manufacturer’s (Jiangsu Hengrui Pharmaceutical Co., Ltd.) recommendation, the initial dose of 300 mg per day is gradually increased to 900 mg per day and then increased according to the patient’s needs, and the maximum dose is 3600 mg per day.

Group B: Patients in group B received fire needle plus cupping (FC) treatment on the basis of treatment in group A.

Acupoints: the main points are Ashi points (lesion area), corresponding nerve segment Jiaji points, and branch ditch points (SJ6); matching points are selected according to syndrome differentiation, pattern of dampness-heat in the liver meridian with Yang Ling Quan (GB34), pattern of dampness-heat in the spleen meridian with Yin Ling Quan (SP9), and pattern of obstruction of collaterals by blood stasis with blood sea (SP10).

Appliances: medium-sized fire needle (diameter 0.4 mm), large-sized fire needle (diameter 0.65 mm), glass fire cup no. 1–5, medical cotton ball, alcohol lamp, lighter, iodophor, etc.

Operation methods: routine disinfection of the skin with iodophor with the order of the head, middle, and tail of herpes will be carried out firstly. Holding 95% alcohol lamp by the left hand close to the needle, and to burn the needle in the right hand to whitening by the external flame of the fire, acupuncturist will prick the head of the herpes cluster. Then, the needles will be pricked into the blisters or rashes quickly from the surface of the skin at the base of the herpes. Pricking early-onset herpes at first, for larger pustules or blood blisters (diameter > 0.5 cm) with a large-scale fire, acupuncturist will extrude blister fluid with disinfection cotton ball after puncture, and then cup with a suitable size of glass fire cup for 5–10 min. If the area of the herpes cluster is too large, more than one cup can be used. The remaining acupoints are treated with fire needle pricking, and each acupuncture point should be pricked three times. Finally, the skin should be sterilized with iodophor more than one time. Postoperatively, the skin was disinfected with iodophor several times, once every other day, for a total of four times.

Skin care: after treatment, the iodophor is used to clean and disinfect the skin and to keep the patient’s skin dry and clean during the treatment.

Course of treatment: the course of treatment is 1 week and from one to four times. If there is no pain any more after one time of FC treatment, the course is just one time. Meanwhile, if the patient still has pain, the FC will continue every other day unless the pain disappears. All the treatments will not be more than four times no matter the pain or not.

Case dropout

1. Subjects who experience other complications, major adverse reactions or specific physiological changes during the trial will be considered unsuitable for further participation and will be excluded from the trial. 2.Subjects have poor compliance. Medication compliance is calculated using the tablet counting method. Medication compliance = dose taken/prescription dose × 100%; medication compliance < 80% or missed fire needle plus cupping treatment ≥ 1 time is defined as poor compliance. 3. Violation of the test plan. Subjects change or add drugs other than the study protocol, and received other treatments other than the study protocol during the trial period. 4. The subject withdrew out by himself. 5. Lost to follow-up at the final stage.

Measures

All patients were to be rigorously recorded for all clinical indicators before and after treatment. The primary outcome is the variability of pain intensity in each group of AHZ patients before and after treatment as estimated by the VAS visual analogue score (VAS 0-100 mm, where 0 mm = painless, 100 mm = most unbearable pain. The higher the number, the more intense the pain).

As a secondary outcome, quantitative scoring methods have been applied to evaluate the symptoms and physical signs before and after treatment, including pain intensity, local itching, burning sensation, rash color, numbers of blisters, clusters, ulcers, fever, local lymphadenopathy, and rash area. Additional secondary outcomes involved analgesic requirements and the occurrence of adverse reactions during the study (including skin burns, needle sickness, subcutaneous haematomas, wound infections, dizziness and head, nausea and vomiting) and the occurrence of PHN after 6 months.

Statistical analysis

Data were analyzed using SPSS 26.0 statistical software. The Shapiro–Wilk test was used to test the normality of the measured data, and Levene's test was used to test the homogeneity of variances. If the data conforms to the normal distribution and the variance is uniform, expressed as mean ± standard deviation ($\overline{\mathcal{X}}\pm \text{SD}$), T-test will be used for difference comparison, and the pairwise comparison will use the LSD method; the differences of non-normal distribution were compared by the Mann–Whitney U test, expressed as the median (quartiles). Count data were described by frequencies (constitutive ratio), and differences were compared by χ² test. All reported P values are two-tailed, and P ≤ 0.05 was considered a statistically significant difference.

Results

A total of 84 AHZ subjects were recruited between January 2018-March 2020 and randomly assigned to groups (Group A: 42, Group B: 42), of which 41 were in Group A, and 42 were in Group B completed the experiment (Fig.1). The differences in general characteristics between groups were not statistically significant upon comparison (Table 1).

Fig. 1.

Flowchart of the trial

Table 1.

Baseline characteristics

Characteristic	Group		p-value
	A	B
	(n = 41)	(n = 42)
Women, No. (%)	22 (53.66)	19 (45.24)	0.443
Age, mean ± SD, years	51.54 ± 16.56	51.90 ± 16.17	0.191
VAS Score, mean ± SD	6.10 ± 1.22	6.43 ± 1.17	0.431
Symptom-Sign Score, mean ± SD	16.63 ± 3.37	16.98 ± 3.51	0.533
Duration of illness, mean ± SD, h	13.73 ± 5.73	11.93 ± 5.51	0.274

Primary outcome

There was no significant difference in VAS scores between the two groups before treatment (p = 0.431). Analysis of the data showed that after one week of treatment, the VAS scores of all groups decreased compared to the pre-treatment (Table 2). The decline value of VAS score in Group B was significantly higher than Group A, indicating that the analgesic effect of FC+ FG was superior to that of FG (p < 0.0001), Fig 2.

Table 2.

Comparison of VAS Score and Symptom-Sign Score

Outcome Measure	A	B	p-value
	(n = 41)	(n = 42)
Comparison of VAS Score
Pre-treatment, mean ± SD	6.10 ± 1.22	6.43 ± 1.17	.431a
Decline Value, median (IQR)	4.00(1.00)	6.00(2.00)	< 0.001b
Comparison of Symptom-Sign Score, mean ± SD
Pre-treatment	16.63 ± 3.37	16.98 ± 3.51	0.533a
Decline Value	11.02 ± 4.23	15.33 ± 3.63	< 0.001a

IQR, Interquartile Range; a. p-value from t-test; b. p-value from Mann–Whitney U test

Fig. 2.

Comparison of VAS score decline values. Note: ****indicates P < 0.0001

Secondary results

There was no significant difference in symptom-sign score between the two groups before treatment (p = 0.533). The results showed that the symptom-sign score of patients in all groups decreased after the final treatment compared to before the first treatment (Table 2). The comparison results between the two group showed that: the difference between Group A and Group B was statistically significant (p < 0.0001), while the decline value of Group B was significantly better than Group A, indicating that FC + FG was significantly better than FG in terms of improvement of signs and symptoms. As shown in Fig. 3.

Fig. 3.

Comparison of decline value of symptom and sign scores. Note ****denotes P < 0.0001

During the whole treatment process, adverse reactions occurred in 9 patients in Group A, of which 3 patients reported dizziness, 3 patients had gastric and epigastric discomfort, and 2 patients experienced constipation, and 1 patient experienced neurasthenia; the rate of adverse reactions was 21.95% (95% CI: 10.56 to 37.61). Two patients in the Group B reacted with discomfort, one showed dizziness and the other experienced gastrointestinal discomfort, with an adverse reaction rate of 4.76% (95% CI: 0.58 to 16.16), and a significant difference in the incidence of adverse reactions between the two groups (p = 0.021), Table 3.

Table 3.

Comparison of adverse effects and PHN

Outcome Measure	No (%) [95% CI]		p-value
	A	B
	(n = 41)	(n = 42)
Comparison of the adverse effects
Yes	9 (21.95) [10.56–37.61]	2 (4.76) [0.58–16.16]	0.021
Comparison of the PHN
Yes	12 (29.27) [16.13–45.50]	2 (4.76) [0.58–16.16]	0.003

A telephone follow-up of all patients participating in the trial by a specific person at month 6 after the end of the trial to ask whether PHN had occurred. Group A reported 12 cases with an incidence of 29.27% (95% CI: 16.13 to 45.50); Group B had 2 cases and its PHN incidence was 4.76% (95% CI: 0.58 to 16.16), and there was a significant difference in the incidence of PHN between the two groups (p = 0.003) (Table 3).

Discussion

This study investigated the efficacy and safety of fire needle plus cupping combined with oral famciclovir and gabapentin for the treatment of AHZ compared to oral famciclovir with gabapentin. It was found that combined therapy had a good analgesic effect on AHZ and relieved various signs and symptoms of patients, which was more excellent than the oral conventional antiviral drug famciclovir and analgesic drug gabapentin. Meanwhile, compared with oral drugs, patients who underwent fire needle plus cupping combined with oral famciclovir and gabapentin have a lower incidence of PHN and fewer adverse reactions.

Rapid pain relief is the primary therapeutic goal for this disease, as it seriously affects the quality of patient survival. Assessment of VAS scores revealed that all therapies provided relief from AHZ pain within 7 days. However, the extent of relief varied, with fire needle plus cupping combined with oral famciclovir and gabapentin being superior compared to oral famciclovir and gabapentin alone. Fire needle plus cupping combined with oral famciclovir and gabapentin has several advantages over oral famciclovir and gabapentin alone in terms of improving clinical signs and symptoms and reducing the incidence of adverse effects and PHN. As a topical treatment, FC reduces the need for systemic drugs and consequently mitigates associated risks. The results of this study provide sufficient evidence for the efficacy and safety of fire needle plus cupping combined with oral famciclovir and gabapentin, and are consistent with the results of previous meta-analysis[28], which suggest that fire-needle based therapies can significantly relieve pain in the treatment of AHZ and reduce the occurrence of PHN.

Research on the treatment of Herpes Zoster (HZ) using fire needle plus cupping has recently been reported. However, to our knowledge, our study represents perhaps the first clinical randomized controlled trial demonstrating the efficacy and safety of this approach for HZ, employing a rigorous design. Unlike previous studies [29–31], we used quantitative rather than qualitative methods to evaluate the comprehensive efficacy of AHZ patients, which made the results more accurate and greatly improved the reliability of the research results. None of the previous studies mentioned the occurrence and treatment of adverse reactions in the experiment, and there are also defects in the allocation, concealment and random methods. Allocation concealment and adequate randomization are effective measures to control selective bias and ensure the authenticity of the results, which need to be described in detail by researchers to ensure the feasibility and repeatability of the study[32].

The mechanism of fire needle therapy has been preliminarily researched in China, revealing that its efficacy in treating various diseases may be attributed to its ability to decrease inflammatory factors while simultaneously increasing the levels of anti-inflammatory factors [33]. The fire needle was evidenced to increase the mechanical pain threshold, significantly reduce the protein expression of IL-1β, TLR4, MyD88, NF-κB, and NLR3 in the disease area, and downregulate the mRNA levels of TLR4 and NLR3, and significantly reduce the serum levels of IL-1β, IL-6, IL-8, TNF-α, and CRP [34–36]. The mechanism of cupping is currently held in various views, among which the theory of promoting blood circulation, increasing metabolism and tissue perfusion is the most recognized [37]. Guo et al. [38]. believe that cupping resembles acupuncture with the ability to convert physical signals into biological signals by stimulating the microenvironment on the body surface, and activating the neuroendocrine immune system through interaction to produce therapeutic effects. These studies established a certain foundation for the development of FC.

There are also some limitations in this study. First, although a sham acupuncture control group was not included in this study, it is important to note that sham acupuncture techniques have been widely used in acupuncture research over the past 20 years, and future studies should consider incorporating such controls to better isolate the placebo effect. Second, since humans are the only host of VZV, animal experiments on acute herpes zoster could not be performed, so the influence of psychological factors and individual immune function in the study results could not be completely excluded. Third, the pain of HZ may increase with the progression of the disease, and also based on ethics, we allow all patients to use temporary analgesics, and the dose of analgesics has a certain fluctuation. Finally, the sample size of the FC group in our study was insufficient, because several patients lost contact with the researchers before formal enrollment. We suspect that the reason may be that the patients lack sufficient understanding and trust in fire needle plus cupping therapy, worry that not taking drugs will lead to poor curative effect, or may be contrary to their own expected therapy. After all, most people want to be treated adequately. This deficiency also reminds researchers that they should adequately communicate with patients prior to the trial to build sufficient trust and maximize the reliability of the trial results.

Conclusion

In conclusion, our study demonstrates that the combination of fire needle plus cupping with medication provides superior pain relief and symptom improvement compared to medication alone in the treatment of AHZ. These findings suggest that fire needle plus cupping may be an effective adjunctive treatment option for AHZ, offering improved outcomes and an enhanced safety profile.

However, it is important to recognize that fire needle plus cupping should be considered as an add-on therapy to standard drug treatment rather than a standalone treatment. Due to the lack of a sham-treated control group, the potential placebo effect associated with invasive therapies like fire needling and cupping, cannot be excluded. Future studies should consider incorporating a sham control group to better isolate the true effects of the treatment and further validate the observed clinical benefits.

Author contributors

Y.Z. and M.J. are the co-first authors of this paper. Y.Z. received the grant and designed the study. Y.Z. drafted the manuscript and received funding for it. Z.L., Q.L. and Q.X. collected the data, Q.X., Q.L. and S.L. were responsible for the experimental fire needle M.J. and S.L. were responsible for processing the data obtained from the experiment, S.L. was the corresponding author of this article, and with Y.Z. was the guarantor of this study. All authors read and approved the final manuscript.

Patient and public involvement

Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

Author contributions

Y.Z. and M.J. are the co-first authors of this paper. Y.Z. received the grant and designed the study. Y.Z. drafted the manuscript and received funding for it. Z.L., Q.L. and Q.X. collected the data, Q.X., Q.L. and S.L. were responsible for the experimental fire needle M.J. and S.L. were responsible for processing the data obtained from the experiment, S.L. was the corresponding author of this article, and with Y.Z. was the guarantor of this study. All authors read and approved the final manuscript.

Funding

This work was supported by the Ministry of Science and Technology of Yunnan Province-Kunming Medical University Joint Project on Applied Basic Research grant number No. 2017FE467 (-147) and the Ministry of Science and Technology of Yunnan Province-Kunming Medical University Joint Project on Applied Basic Research grant number No. 202201AC070578 and the Postgraduate Program of Yunnan Provincial Department of Education (2022Y334).

Availability of data and materials

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Conflict of interest

The authors declare no competing interests.

Ethics approval and consent to participate

The study has been approved by the Medical Ethics Committee of Yuxi People’s Hospital (No.: 20170730–01). Written informed consent will be obtained from each participant.

Consent for publication

Not applicable.