This is a prospective, multicenter, parallel-group, participant- and assessor-blinded randomized trial comprising a comparison between acupuncture and SA treatment for IGT in obese or overweight participants. All procedures and time frames are displayed in Figure 1 as per the guideline CONSORT.

A total of 196 participants with IGT who are overweight/obese will be recruited from three different hospitals, Guang’anmen Hospital, Shenzhen Luohu District Traditional Chinese Medicine Hospital, and Yan Tai Hospital of Traditional Chinese Medicine, through public advertisements like posters, hospital websites, WeChat public accounts, and the Internet from October 2022 to December 2024. The research staff will introduce the background and process of the study in detail to potential subjects who contact the research team and express interest to participate. Once the informed consent form is signed, participants will be evaluated for eligibility by medical history inquiries, physical examinations, and necessary chemical examinations. The duration of the study for each participant will be 37 weeks, including 1-week baseline period, a 12-week treatment period, and a 24-week follow-up period.

The trial will adopt the diagnostic criteria of the World Health Organization [WHO (39)] for IGT (40) and the diagnostic criteria for overweight/obesity in the guidelines for the Prevention and Control of overweight and Obesity in Chinese Adults formulated by the Ministry of Health of China in 2003 (41, 42):

Note: The above two criteria should be met at the same time.

Participants who meet all of the following criteria might be eligible: (1) those who meet the diagnostic criteria for overweight/obesity and IGT; (2) 18–60 years old; (3) those who can appropriately describe their wishes, voluntarily fill in the informed consent form, and agree to participate in clinical trials.

Note: The above three criteria should be met at the same time.

Participants will be excluded if they meet any of the following criteria: (1) obesity secondary to heredity, drugs, and diseases; (2) those who have received weight-loss treatment or antidiabetic treatment including acupuncture, drugs, herbal medicine, and nutrient supplements in the past 3 months; (3) those who have taken drugs that have known effects on body weight or appetite in the past 3 months, such as corticosteroids, antidepressants, non-selective antihistamines in vivo, and nicotine substitutes; (4) IGT caused by abnormal thyroid function, endocrine tumors, or extensive liver damage; (5) abnormal glucose tolerance caused by thiazide diuretics, β-blockers, nicotinic acid drugs, quinolones, calcineurin inhibitors, interferon-alpha, etc.; (6) participants with serious primary diseases such as heart, lung, brain, liver, or hematopoietic system diseases, progressive malignant tumor, or other serious consumptive diseases; (7) participants with cognitive impairment and severe mental illness; (8) participants with blood coagulation dysfunction and who are scare of needles; (9) pregnant, breastfeeding, or planning to conceive within 37 weeks.

Note: Participants who meet any of the above criteria should be excluded.

A random number will be generated with the SPSS software and concealed in opaque random envelopes. The envelopes will be prepared by a third party in advance, with the sequence number labeled on the surface and the random number and group allocation information sealed in. The random envelopes will be preserved by special personnel who are not involved in treatment and evaluation.

The participants will be blinded to the group allocation in this study, while the acupuncturists will not be blinded. The outcome will be evaluated by independent assessors who will be blinded to the allocation to minimize the bias associated with data collection. The statisticians will also be blinded to the allocation.

Study group: acupuncture + lifestyle recommendation; control group: sham acupuncture + lifestyle recommendation.

During the 12-week treatment, participants in both the acupuncture and SA groups will receive 30-session treatment, three times per week (once every other day) in the first six weeks and twice per week (with an interval of 2–3 days) in the last six weeks. Certified acupuncturists with no less than one year of clinical experience will perform the treatment. Acupuncture needles (Huatuo, Suzhou Medical Appliance) with the size of 0.3 mm × 40-75 mm will be used in the acupuncture group, while, acupuncture needles (Huatuo, Suzhou Medical Appliance) with the size of 0.2 mm × 25-40 mm will be used in the SA group. The participants in different groups will be treated separately to avoid contamination during the process.

The acupuncture point regimen is based on evidence-based clinical practice guidelines of traditional Chinese medicine (43, 44). All acupoints selected and their locations are displayed in Figures 2, 3. For acupoints EX-B3 (Yishu), BL18 (Gansu), BL20 (Pishu), and BL21 (Weishu), needles will be inserted at a depth of 15–25 mm depending on the participants’ somatotype and at an angle of 20° obliquely downward. The needles will be gently rotated and lifted three times to achieve a sense of sourness, distention, and heaviness (de qi), and will be withdrawn afterward immediately.

For GV20 (Baihui), the needle will be inserted backward under the cap membrane at an angle of 45° with the scalp; for GV29 (Yintang), the needle will be inserted downward at an angle of 15° under the periosteum; making the participant feel heavy pressure and acid distension. For acupoints LI11 (Quchi), CV12 (Zhongwan), CV10 (Xiawan), ST25 (Tianshu), CV6 (Qihai), CV4 (Guanyuan), ST40 (Fenglong), and SP6 (Sanyinjiao), needles will be inserted at a depth of 25–35 mm vertically. The needles will be gently rotated and lifted three times to achieve a sense of sourness, distention, and heaviness (de qi). The needles will be retained for 30 min with gentle lifting, thrusting, and twirling every 10 min during each session.

Acupoint location refers to the standard of acupoint location in the western Pacific region of the WHO and the name and location of acupoints (GB/T12346-2006).

Participants in the SA group will receive minimal acupuncture at sham acupoints, which are located at a horizontal distance of one B-cun (≈ 20 mm) to the points used in the acupuncture group.

For sham EX-B3, BL18, BL20, and BL21, needles will be vertically inserted at a depth of 1–2 mm without any manipulation to avoid de-qi sensation and will be withdrawn immediately afterward.

For sham GV20, GV29, LI11, CV12, CV10, ST25, CV6, CV4, ST40, and SP6, needles will be vertically inserted at a depth of 1–2 mm without any manipulation to avoid the de-qi sensation. The needles will be retained for 30 min during each treatment session.

Lifestyle recommendations will be made based on expert consensus and previous large-scale studies (45, 46). After randomization, participants in both the acupuncture and the SA groups will receive a brochure with lifestyle recommendations and a 20–30-min face-to-face communication with related specialists on the importance of a healthy lifestyle for the management of IGT and obesity. Specifically, the participants will be encouraged to lose 5∼10% of their initial weight via an integrated strategy of diet and exercise. They will be encouraged to limit calorie intake, reducing at least 400–500 kCal daily, to increase their activity gradually according to their individual situation, with the goal of over 30-min medium-or high-intensity physical activities such as brisk walking. Medium- or high-intensity physical activities are defined as reaching 50-70% of the maximum heart rate, being a little strenuous, and having fast breathing but no shortness of breath during exercise. The participants will be encouraged to avoid excessive alcohol intake and quit smoking. Whether these recommendations have been accepted and conducted will be evaluated during each visit.

The participants will not be encouraged to receive any other treatment or medication for IGT or obesity/overweight during the study period to avoid any influence on the results. If participants receive any other treatment, they will also be included in this study, but all details will be recorded in the case report form.

If diabetes is diagnosed during the study period and regular hypoglycemic drugs are recommended by the specialists, the participants will be allowed to use hypoglycemic drugs for rescue. The details (name, dosage, frequency, start time, and duration of use) of drugs will be documented. The proportion of participants using rescue drugs in the groups will be compared.

Participants’ expectations of acupuncture will be evaluated with reference to previous high-quality acupuncture clinical trials (51, 52). The participants will be assessed at baseline by the following two questions: “Do you think acupuncture will be effective in treating the illness?” and “Do you think acupuncture will be effective in controlling weight and decreasing glucose?” The response options will be “Ineffective,” “the effect is not good,” “uncertain,” “has some effect,” or “very effective.”

Blinding will be assessed using the James and Bang blinding indices (53). The participants will be told that they are 50% likely to be allocated to the traditional acupuncture group with deeper needling or to the modern acupuncture group with shallower needling. After the last treatment on week 12, each participant will be assessed with a questionnaire asking, “do you receive traditional acupuncture?,” with choice options of Yes or No.

Compliance on acupuncture will be estimated by counting how many times the subjects have received the treatment, and the criterion for good compliance will be 80% and above. The calculation formula is as follows: compliance = (the number of times the subject has received treatment/the total number of times the subject should receive the treatment) × 100%.

The participants lifestyle adjustment diary card, dietary change table, dietary compliance questionnaire, and exercise compliance scale were selected to evaluate the compliance on lifestyle recommendation.

The participant’s lifestyle adjustment diary card is a record of the completion of daily life guidance (complete “√,” unfinished “ × ,” to be checked every day). The dietary compliance questionnaire is extracted from the dietary treatment compliance questionnaire for patients with type 2 diabetes mellitus (54). It contains four questions concerning whether they eat strictly according to the dietary instruction plan, regular and quantitative meals, weigh or accurately measure food per meal, and use the Food Exchange scale to arrange their diet. Each question is provided with four options: it cannot be done at all, it can be done occasionally, it can be done basically, and it can be done completely.

The dietary change table before and after treatment included staple food and high-calorie non-staple food, and the options included “more than before treatment,” “more increase than before treatment,” “no change,” “less than before treatment,” and “more reduction than before treatment.”

The exercise compliance scale refers to the exercise compliance section of the coronary heart disease self-management scale (55). The question is “how did you participate in the recommended activities and exercise in the past month?” The options are: never participated in recommended activities (such as brisk walking, swimming, dancing, and Taijiquan), participated in recommended activities for less than 30 min per week, participated in recommended activities for 30–60 min per week, participated in recommended activities for 1–3 h a week, or participated in recommended activities for more than 3 h a week.

The specific outcome measures and time frame are displayed in Table 1.

Adverse events (AEs) will be reported by the participants themselves and evaluated by outcome assessors and recorded in detail on AE forms throughout the study period. Based on their potential association with the intervention, AEs will be categorized by acupuncturists and related specialists as treatment-related or non-treatment-related within 24 h of occurrence. Treatment-related AEs include but not limited to broken needles, hematoma, infection, abscess around the location of the needle insertion, fainting, vomiting, nausea, palpitations, dizziness, anorexia, and insomnia that presented during or after acupuncture. Non-treatment-related AEs refer to any other unexpected AE that happened after the initiation of the study. According to the evaluation criteria of the NHS Committee (56), AEs will be divided into three levels (severe, moderate, and mild). Standardized procedures for AE management, especially for serious AEs, will be prepared, and all researchers and doctors involved will be trained.

Before the trial, all staff will undergo special training on the purpose and content of the trial, treatment strategies, and quality requirements. Monitors will check the participant adverse event table, the participants’ lifestyle recommendation diary card, case report form, etc. once every week as well as the acupuncture operation during the treatment period. Dropouts and withdrawals and the underlying reasons will be documented in detail throughout the trial.

In this study, change in 2hPG from baseline will be used as the basis for primary sample size estimation, based on the unpublished preliminary data collected from 10 participants in the acupuncture group and 10 SA group controls (-1.16 ± 0.42 mmol/L VS0.97 ± 0.34 mmol/L), and a sample size of 196 participants (98 per group) will need to provide the trial with 80% power with a two-sided significance level of 0.05 and 10% dropouts. The PASS 15 software was used for sample size calculation.

We will use the SPSS V.25 software (IBM Corp., Armonk, NY, United States) to perform all statistical analyses following the intention-to-treat principle. CI will be established at 95% and significance level at 0.05. Missing data will be calculated using the actual observational value without imputation if the dropout rate is no more than 5%. For continuous data, the data will be presented as mean ± SD if normally distributed or as median (IQR) if not normally distributed. Longitudinal continuous data will be compared between the groups by repeated-measures analysis of variance (ANOVA) including group and time–group interaction. Other continuous data will be analyzed by Student’s t-test and Wilcoxon rank-sum test, and categorical data by X ² test or Fisher’s exact test, as appropriate. Linear correlation analysis will be conducted to measure the closeness of linear correlation between variables. Sensitivity analysis will be performed if necessary. A p-value < 0.05 will be considered statistically significant.