If you design a clinical trial badly, you might get an invalid result: Laser- vs electro-acupuncture

There are many variations of acupuncture. Electroacupuncture (EA) and Laseracupuncture (LA) are but two examples both of which are commonly used. However, it remains uncertain whether LA is as effective as EA. This study aimed to compare EA and LA head to head in dysmenorrhea.

A crossover, randomized clinical trial was conducted. EA or LA was applied to selected acupuncture points. Participants were randomized into two sequence treatment groups who received either EA or LA twice per week in luteal phase for 3 months followed by 2-month washout, then shifted to other groups (sequence 1: EA > LA; sequence 2: LA > EA). Outcome measures were heart rate variability (HRV), prostaglandins (PGs), pain, and quality-of-life (QoL) assessment (QoL-SF12). We also compared the effect of EA and LA in low and high LF/HF (low frequency/high frequency) status.

43 participants completed all treatments. Both EA and LA significantly improved HRV activity and were effective in reducing pain (Visual Analog Scale [VAS]; EA: p < 0.001 and LA: p = 0.010) and improving QoL (SF12: EA: p < 0.001, LA, p = 0.017); although without intergroup difference. EA reduced PGs significantly (p < 0.001; δ p = 0.068). In low LF/HF, EA had stronger effects than LA in increasing parasympathetic tone in respect of percentage of successive RR intervals that differ by more than 50 ms (pNN50; p = 0.053) and very low-frequency band (VLF; p = 0.035).

The authors concluded that there is no significant difference between EA and LA in improving autonomic nervous system dysfunction, pain, and QoL in dysmenorrhea. EA is prominent in PGs changing and preserving vagus tone in low LF/HF; yet LA is noninvasive for those who have needle phobia. Whether LA is equivalent with EA and the mechanism warrants further study.

Looking at the affiliations of the authors, one might expect that they should be able to design a meaningful study:

• ¹Division of Hemato-Oncology, Department of Internal Medicine, Branch of Zhong-Zhou, Taipei City Hospital, Taipei, Taiwan.
• ²Institute of Traditional Medicine, National Yang-Ming Chiao Tung University, Taipei, Taiwan.
• ³Department of Traditional Medicine, Branch of Yang-Ming, Taipei City Hospital, Taipei, Taiwan.
• ⁴Department of Traditional Medicine, Branch of Kunming, Taipei City Hospital, Taipei, Taiwan.
• ⁵Department of Gynecology and Obstetrics, Branch of Yang-Ming, Taipei City Hospital, Taipei, Taiwan.

Sadly, this assumption is evidently mistaken.

The trial certainly does not show what they claim and neither had it ever the chance to show anything relevent. A clinical trial is comparable to a mathematical equation. It can be solved, if it has one unkown; it cannot produce a result, if it has two unknowns.

The efficacy of EA and LA for dysmenorrhea are both unknown. A comparative study with two unknowns cannot produce a meaningful result. EA and LA did not both improve autonomic nervous system dysfunction, pain, and QoL in dysmenorrhea but most likely they both had no effect. What caused the improvement was not the treatment per se but the ritual, the placebo effect, the TLC or other non-specific factors. The maginal differences in other parameters are meaningless; they are due to the fact that – as an equivalence trial – the study was woefully underpowered and thus open to coincidental differences.

Clinical trials should be about contributing to our knowledge and not about contributing to confusion.