Acupoint Catgut Embedding With Laser Acupuncture for Weight Loss in Adults With Obesity

Background

Acupoint catgut embedding and laser acupuncture have each accumulated clinical evidence as treatments for obesity in adults, but three gaps remain. First, the two have not been evaluated in combination. Second, few published trials measure anthropometric, biochemical, and blood pressure outcomes together. Third, most existing trials are small, and systematic reviews have repeatedly noted limitations in blinding and sham control. Supporting literature is listed under Citations.

Rationale for the design

Acupoint embedding delivers sustained mechanical stimulation as the suture degrades over several weeks, whereas laser acupuncture delivers an energy input at the time of each session. The two therefore differ in mechanism and in time course. By giving identical acupoint embedding to both groups and varying only whether the laser emits energy, the trial estimates the incremental effect attributable to laser acupuncture rather than the combined effect of the two therapies.

Masking

Masking is implemented at four levels. Participants are masked because 810 nm light is outside the visible range and safety goggles are worn during treatment. The treating physician is masked because the manufacturer supplies dedicated sham pens whose housing, red indicator light, and operating sound are identical to the active pens but whose laser module is disconnected, giving an actual output of 0 milliwatts. The research assistants who perform all measurements take no part in treatment and are not informed of allocation. The statistician works from coded group labels until unmasking. Active and sham pens are managed by a study coordinator who takes no part in treatment; pens carry only a serial number with no active or sham marking, and the code list is held sealed in a safe in the principal investigator's office, to be opened only for a serious adverse event or a genuine medical emergency.

Randomization

A permuted block randomization sequence, with block size randomly set to 4 or 6 and an allocation ratio of 1:1, is generated in advance with the R blockrand package by an independent statistician who takes no part in enrollment or treatment, stratified by sex and by body mass index category (less than 30 versus 30 kg/m^2 or greater). Allocation is implemented using sequentially numbered opaque sealed envelopes.

Statistical analysis

The primary analysis follows the intention-to-treat principle using a linear mixed-effects model containing group, time, the group-by-time interaction, the baseline value, the stratification factors, and a random participant effect. The Week 12 group-by-time contrast is reported as a least-squares mean difference with a 95 percent confidence interval. Missing data are handled by the model under a missing-at-random assumption, with last-observation-carried-forward and multiple imputation (20 imputations) as sensitivity analyses. A per-protocol analysis, defined as completion of at least 80 percent of treatment sessions with no major protocol violation, is a further sensitivity analysis. Secondary anthropometric outcomes use the same mixed-model structure. Biochemical outcomes use mixed models or analysis of covariance with the baseline value as covariate, with log transformation for skewed variables such as triglycerides and the homeostatic model assessment of insulin resistance. Blood pressure is analyzed by analysis of covariance at Week 12. Secondary outcomes are prespecified but are not adjusted for multiplicity; effect sizes and 95 percent confidence intervals are reported for each. Prespecified subgroup analyses are by sex and by body mass index category. The significance level is two-sided alpha of 0.05.

Sample size

The sample size is based on the primary outcome of weight change. With a standardized effect size of 0.67, two-sided alpha of 0.05, and 80 percent power, 35 participants per group are required. Allowing for 15 percent attrition and providing power for the secondary metabolic outcomes, the enrollment target is 60 participants per group, 120 in total.

Safety monitoring

Expected reactions to acupoint embedding include transient pain, bruising, or a mild nodule at the insertion site, usually resolving within days to two weeks. Less common events include local infection, allergic reaction, or suture extrusion. Reported adverse events from laser acupuncture are limited to transient warmth or erythema. Any serious adverse event, defined as one causing hospitalization, a life-threatening event, permanent disability, or death, is reported to the ethics committee and the principal investigator within 24 hours. Given the anticipated risk profile of the interventions, an independent safety monitor rather than a data and safety monitoring board oversees safety. The monitor reviews a safety summary monthly, the study coordinator compiles a safety data summary for the monitor every 3 months, and a formal interim safety review is conducted when enrollment reaches 60 participants.

Quality control

Physicians performing embedding and laser treatment must hold a license in Chinese medicine, have at least 2 years of clinical embedding experience, and complete laser acupuncture operator training, together with standard operating procedure training and simulated cases before enrollment begins. Laser output is verified monthly with an optical power meter, and a deviation of more than 10 percent triggers recalibration; the sham pens are confirmed to output 0 milliwatts. Measurement assistants complete standardized training and must reach an inter-rater intraclass correlation coefficient above 0.90.