Study design
This randomized, participant-blind, sham controlled trial will be conducted at Long-Hua Hospital affiliated to Shanghai University of Traditional Chinese Medicine in China. The protocol for this trial is reported based on the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 Checklist: defining standard protocol items for clinical trials (Additional file 1). The study has been approved by the Ethics Committee of Long-Hua Hospital (Ethical approval number: 2016LCSY028), and registered on the Chinese Clinical Trial Registry (Chictr) platform since 29 December 2018 (Registration number: ChiCTR1800020444). A flow diagram of the trial is shown in Fig. 1.
Patient recruitment
Patients meet the American Diabetes Association (ADA) 2012 diagnostic criteria for DPN will be recruited from the endocrinology departments of Long-Hua Hospital affiliated to Shanghai University of Traditional Chinese Medicine in Shanghai, China. Recruitment posters will be posted in the hospital and uploaded to social media (WeChat) from October 2016 to December 2021. All patients will be required to provide written informed consent (Additional file 2) before randomization.
Inclusion criteria
Participants who meet all the following requirements will be allowed for enrollment:
1. Aged 18–75 years (either sex);
2. Patients who meet diagnosis of DPN defined by ADA in 2005 [12].
a. DPN is defined as the presence of symptoms and/or signs of peripheral nerve dysfunction in people with diabetes, after the exclusion of other causes.
b. NP is defined as altered sensitivity to pressure and (1) altered sensitivity to pain or (2) altered sensitivity to vibration or (3) achilles reflex [13].
3. Symmetric and predominantly sensory, starting from the lower limbs distally and gradually spreading proximally in a glove-and-stocking distribution;
4. Ability to understand study procedures and willingness to comply with them for the entire period of study;
5. Written informed consent
Exclusion criteria
Participants meeting any of the following criteria will be excluded:
- PN caused by conditions other than diabetes (e.g., alcohol abuse, chemotherapy, hereditary causes, chronic inflammatory or idiopathic PN);
- Psychiatric illnesses other than mild depression;
- Severe or unstable cardiovascular, liver, kidney, respiratory or hematological disorders;
- Received acupuncture treatment in the last 3 months;
- Pregnant or lactating women;
- Research unit personnel directly related to the study and their immediate family members;
- Incapable of giving informed consent or following the study instructions due to language disturbances, serious cognitive deficits, or lack of time;
- Currently participating in other clinical trials.
Randomization and allocation concealment
All eligible patients will be randomly assigned to manual acupuncture (MA) group or sham acupuncture (SA) group in a 1:1 ratio. The blocked randomization sequence will be computer-generated (EXCEL) by an independent statistician, who will not be involved in implementation and statistical analysis of the trial. The allocation will be placed inside sequentially numbered sealed opaque envelopes which will be opened only after enrollment. The treatment allocation will be revealed to acupuncturists out of patients’ sight to ensure blinding. To reduce the risk of observer bias, the acupuncture practitioners will be discouraged from discussing treatments or previous results with patients. The random allocation sequence and sealed opaque envelopes will be kept separately by two specific researchers. The clinical research coordinator will be responsible for enrolling patients, obtaining informed consent and requesting randomization.
Masking
Due to the nature of acupuncture, masking of acupuncturists is quite difficult to achieve. Patients, outcome assessors, and statisticians who perform the statistical analyses will be blinded to group assignment. The treatments subjects received will be not revealed until the statistical analysis is completed.
Interventions
Treatment will be performed by licensed acupuncturists who have at least five years of experience in acupuncture. All the acupuncturists will be trained how to locate acupoints, puncture, and manipulate needles before trials. A placebo device [14,15] will be applied in both groups for better implementation of blindness. Both MA and SA treatments will consist of 24 sessions over 12 weeks (40 min per session, two sessions per week). Acupuncture will be discontinued if patients suffer from any serious adverse events (AEs).
Manual acupuncture
Patients allocated to MA group will receive treatment with needles being inserted at the prespecified acupuncture points through the placebo device. Obligatory and additional acupoints adopted in this protocol are developed from clinical experiences of acupuncture experts. The obligatory acupoints include Zhongwan (CV12), bilateral Weiwanxiashu (EX-B3), bilateral Ganshu (BL18), bilateral Pishu (BL20), bilateral Shenshu (BL23)，bilateral Zusanli (ST36), bilateral Yanglingquan (GB34), bilateral Sanyinjiao (SP6), bilateral Taixi (KI3), and Bafeng (EX-LE10). Additional acupoints Baxie (EX-UE9) will be added when patients’ symptoms appear not only in the lower limbs but also in the upper limbs. All acupoints are localized according to the WHO Standard Acupuncture Locations and exhibited in Table 1 and Fig. 2. After skin disinfection, disposable, stainless steel acupuncture needles (0.25 × 25mm or 0.25 × 40mm, provided by Wuxi Jiajian Medical Instrument Co. Ltd., China) will be inserted into the skin of acupoint (approximately 10-20mm depth), then manipulations of twirling, lifting and thrusting will be performed on all needles for at least 10s to reach De qi (a compositional sensation including soreness, numbness, distention and heaviness), which is believed to be an essential component for acupuncture efficacy. Firstly, CV12, ST36, GB34, SP6, KI3, EX-LE10 and EX-UE9 will be punctured when patients lie supine. Then, EX-B3, BL18, BL20 and BL23 will be punctured when patients lie prone. Needles will be retained in these acupoints for 20min.
Sham acupuncture
Patients in SA group will receive sham acupuncture. The procedure and duration of treatment in the SA group will be identical in the MA group except the needles (0.25 × 25mm, blunt tip, provided by Wuxi Jiajian Medical Instrument Co. Ltd., China) are blunt tip and there will be no skin penetration and needle manipulation for De qi.
Although it is difficult to set an eligible placebo control, using blunt tipped needles which do not penetrate patient’s skin is the most common approach for administering sham treatments among acupuncture trials, according to a literature review [16,17]. Moreover, this study will exclude those who have received acupuncture treatment in the last 3 months and can distinguish SA from MA. The same control with no skin penetration at acupoints was adopted and succeeded in masking patients with DPN [7, 14, 15, 18]. Furthermore, all patients will be asked to guess which treatment they have received to test the patient-blinding effects at week 12.
Table 1 Locations and manipulations of acupoints
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Acupoint
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Location
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Manipulation
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Obligatory acupoints
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Zhongwan (CV12)
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On the anterior midline, 4 cuna above the umbilicus
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Puncture perpendicularly to a depth of 1.0-1.2 cun
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Weiwanxiashu (EX-B3)
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at the same level as the inferior border of the spinous process of the 8th thoracic vertebra (T8), 1.5 cun lateral to the posterior median line
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Puncture obliquely and medially to a depth of 0.5-0.8 cun
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Ganshu (BL18)
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at the same level as the inferior border of the spinous process of the 9th thoracic vertebra (T9), 1.5 cun lateral to the posterior median line
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Puncture obliquely and medially to a depth of 0.5-0.8 cun
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Pishu (BL20)
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at the same level as the inferior border of the spinous process of the 11th thoracic vertebra (T11), 1.5 cun lateral to the posterior median line
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Puncture obliquely and medially to a depth of 0.5-0.8 cun
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Shenshu (BL23)
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at the same level as the inferior border of the spinous process of the 2nd lumbar vertebra (L2), 1.5 cun lateral to the posterior median line
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Puncture perpendicularly to a depth of 0.8-1.2 cun
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Zusanli (ST36)
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3 cun directly below Dubi (ST35), and one finger-breadth lateral to the anterior border of the tibia
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Puncture perpendicularly to a depth of 1.0-1.2 cun
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Yanglingquan (GB34)
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in the depression anterior and distal to the head of the fibula
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Puncture perpendicularly to a depth of 1.0-1.2 cun
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Sanyinjiao (SP6 )
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3 cun superior to the prominence of the medial malleolus, posterior to the medial border of the tibia,
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Puncture perpendicularly to a depth of 1.0-1.2 cun
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Taixi (KI3)
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in the depression between the prominence of the medial malleolus and the calcaneal tendon
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Puncture perpendicularly to a depth of 0.5-0.8 cun
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Bafeng (EX-LE10)
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on the dorsum of the foot, between the first and fifth toes at the junction of the red and white skin posterior to the margin of the web; 4 points on each foot, 8 in total
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Puncture obliquely and medially to a depth of 0.5-0.8 cun
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additional acupoints for upper limbs syndrome
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Baxie (EX-UE9)
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at the dorsum of the hand，between the first and fifth fingers, proximal to the web margins between the five fingers at the junction of the red and white skin, 4 points on each hand,8 in total
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Puncture obliquely upward to a depth of 0.5-0.8 cun
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a1 cun (≈20mm) is defined as the width of the interphalangeal joint of patient’s thumb
Concurrent Treatments
Participants will receive routine health care as provided to all other patients with DPN. These treatments include glucose control, antihypertensive therapies, dyslipidemia control, analgesic and neurotrophic treatments, if necessary. All information regarding the use of medications (including date of administration, types and dosage) will be recorded. This will contribute to improving adherence.
Follow-up
After 12-week treatments, all participants will enter an additional 3 months follow-up period. During this time, they will receive routine health care as provided to all other patients with DPN. However, acupuncture treatment will not be permitted during follow-up.
Outcomes
Primary outcome
The primary outcome is peroneal motor nerve conduction velocity (peroneal MNCV) which will be assessed at baseline and at week 12 after randomization.
Key secondary outcomes
Secondary outcomes include peroneal motor nerve action potential amplitude (peroneal MNAP) and latent period (peroneal MNLP), sural sensory nerve conduction velocity (sural SNCV), action potential amplitude (sural SNAP) and latent period (sural SNLP). The outcome measurements will be assessed at baseline and at week 12 after randomization.
Additional secondary outcomes include: Glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), 2-hour postprandial blood glucose (2hPG), Body mass index (BMI) and blood pressure (BP). The outcome measurements will be assessed at baseline and at week 12 after randomization.
Michigan Neuropathy Screening Instrument (MNSI) score
The MNSI is a clinical and semi-quantitative evaluation of neuropathy that includes medical history and physical assessment. Medical history will be completed by patients with score ranging between 0 and 13. Physical assessment will be completed by health professionals with five indicators and the aggregate score ranging between 0 and 10: foot appearance (0 and 1 for normal and abnormal, respectively), ulceration (0 and 1 for normal and abnormal, respectively), ankle reflex (0, 0.5, and 1 for normal, reenforced, and absent, respectively), vibration test (0, 0.5, and 1 for normal, weakened, and absent, respectively), and monofilament examination (0, 0.5, and 1 for normal, weakened, and absent, respectively) of feet on both sides. The outcome measurement will be assessed at baseline, at week 12 and at month 6 after randomization.
Quality of life (QoL)
Disease-specific QoL will be assessed at baseline and at week 12, month 6 after randomization using Diabetes Specific Quality of Life scale (DSQL). The scale consists of four domains: interference (12 items), psychology (8 items), social relations (4 items) and treatment (3 items). Each item is measured with a 5-point Likert scale ranging from “not at all” to “extremely”. Higher scores indicate worse QoL.
Patients’ global assessment of DPN
Patients’ global assessment of DPN will be evaluated on a 5-point Likert scale at week 12. Patients will be asked to respond to the following question: “Considering all the ways your DPN affects you, how are you doing today?” 1=very poor; 2=poor; 3=fair; 4=good; or 5=very good.
Blinding assessment
To test the patient-blinding effects, all patients will be asked to guess their group assignment allocation within 2min after the last treatment session at week 12 as following: “Which group do you think you are in?” A. traditional acupuncture; B. modified acupuncture; or C. not sure.
Table 2. Expectations for the efficacy of acupuncture are varied. If using following statements to describe your views on your disease/symptoms after the entire course of treatment, how much do you agree? For each statement, please choose the closest answer.
Credibility and expectancy
Credibility and expectancy of patients will be assessed by a Likert-scale Credibility/Expectancy Questionnaire (see Table 2) before the first treatment.
Adverse events
AEs data will document the occurrence, duration, and severity of adverse reactions (symptoms and signs), and how the event was resolved (or not) during the treatment. Based on their potential association with the acupuncture needling procedure, AEs will be categorized by acupuncturists and related specialists as treatment-related or not within 24h after occurrence. Common treatment-related AEs include local subcutaneous hematoma, itching at the sites of needle insertion, continuous post-needling pain, dizziness, and so on. All participants will receive routine blood test, liver function (alanine transaminase and aspartate transaminase), and kidney function tests (serum creatinine and blood urea nitrogen). These tests will be performed twice, after randomization and at the end of 12-week treatment period. Serious adverse events will be reported to Medical Ethics Committee and the participant will be treated with relevant conventional therapy or hospitalization if necessary (the participant’s allocated intervention will be revealed).
Assessment of safety
Patients will be asked to assess safety of treatments after 12 weeks’ treatments, using a four-grade scale: safe, relatively safe, unsafe, and very unsafe.
Sensation during the treatment
Patients will be asked about their sensation during each treatment period as following: “What sensation do you feel during the treatment? A. soreness; B. distention; C. pain; D. no feeling; E. else, please specify___.”
Usage of medication
Medication Usage Log: Participants will be given a printed log to record their daily intake of prescribed medications. We will measure outcomes at week 12.
The schedule of enrollment, interventions, and assessments are presented in Fig. 3.
Data collection, management and monitoring
All researchers including acupuncturists, outcome assessors, and statisticians will receive training regarding data management. Case Report Forms (CRFs) will be completed and double entered into the Electronic Data Capture (EDC) system by two independent investigators to ensure accuracy of data.
All research documents, including both paper files and electronic documents, will be preserved for at least five years after publication. If reviewers or readers have any questions regarding our published data, they can contact corresponding author for access to original data or visit ResMan (http://www.medresman.org/uc/project/projectadd.aspx). Private information of patients including name, telephone number and ID number will be anonymous to ensure participant confidentiality.
Safety of this study will be monitored by a team consists of independent clinical experts and statisticians with access to unblinded data from Data and Safety Monitoring Board (DSMB) of the clinical evaluation center of Long-Hua Hospital, affiliated to Shanghai university of TCM. DSMB is independent from the sponsor, the competing interests and the investigational site and will review performance and safety of the trial every six months.
The criteria for unblinding and discontinuing allocated interventions for any trial participant experiencing serious acupuncture-related AEs have been described previously. DSMB will reveal a participant’s allocated intervention, and make the final decision on whether to terminate the trial.
Statistical methods
Sample size
Based on results of a previous study, a sample size of 47 participants per group was estimated to provide 80% power to detect a between-group difference of 2.4 m/s of conduction velocity improvement of common peroneal nerve, with a pooled standard deviation of 4.15 m/s and an alpha level of 0.05. The assumption of a conservative 20% drop-out rate in any group increases the sample size to 59 participants per group or 118 participants in total.
Statistical analysis
Statistical analysis will be performed by an independent statistician who is not aware of group allocation. SPSS 21.0 (IBM SPSS Statistics, New York, USA) will be used for data analysis. Level of significance will be established at α< 0.05 with a two-sided test. Continuous data will be represented by mean ± standard deviation or median (range), and categorical data will be represented by percentage. All efficacy analyses will be performed using the intent-to-treat (ITT) approach. For the ITT analysis, population will consist of all patients who have been randomized. Missing data will be imputed using the last observation carried forward (LOCF) method. Continuous variables will be compared using Student’s t-test or Wilcoxon rank-sum test as appropriate. Categorical variables will be compared using Fisher’s exact test or Wilcoxon rank-sum test as appropriate. Analysis of covariance (ANCOVA) or logistic regression will be used for analysis and adjustment of baseline characteristics that differ significantly between two groups.
Ethics and dissemination
The study protocol which follows principles of the Declaration of Helsinki has been approved by the Medical Ethics Committee of Long-Hua Hospital affiliated to Shanghai University of Traditional Chinese Medicine since 7 July 2016 (Approval Number: 2016LCSY028) and registered on the Chinese Clinical Trial Registry, ChiCTR1800020444. Results will be disseminated through peer-reviewed publications, a master’s thesis, or conference presentations. Data will be anonymized prior to publication to prevent identification of individual participants.