Acupuncture for the Treatment of Tension-Type Headache: An Overview of Systematic Reviews

Tension-type headache is the most common type of headache among adults and represents the second most frequent chronic disease worldwide, causing a significant impact on mood, work, and daily activities of those affected. Although the exact cause of this condition is not yet fully understood, it is believed to involve both mechanisms related to the muscles of the head and neck, as well as alterations in the central nervous system that affect natural pain control. Because of this complexity, treatment can be challenging, and medications, physical therapy, and relaxation techniques are commonly used. Acupuncture has frequently been employed as a complementary treatment for headache and is recommended by the European Federation of Neurological Societies as a therapeutic option for tension-type headache.

Chinese researchers conducted a broad study to assess the quality and reliability of scientific evidence on the use of acupuncture in the treatment of tension-type headache. To this end, they performed what is called an "overview of systematic reviews," a special type of research that analyzes and compares multiple scientific studies already published on the same topic. The objective was to examine both the methodological quality and the quality of evidence of eight systematic reviews and meta-analyses that evaluated the efficacy of acupuncture for this condition. The researchers conducted comprehensive searches in major scientific databases, including publications in both English and Chinese, covering studies published from the inception of these databases through September 2019.

To assess the methodological quality of the included studies, the researchers used a specific tool called AMSTAR-2, which examines 16 different aspects of conducting a systematic review, seven of which are considered critical to the reliability of the results. In addition, they used the GRADE system to assess the quality of evidence presented in each study, considering factors such as risk of bias, inconsistencies among studies, precision of results, and possibility of publication bias. The reviews analyzed included studies that compared acupuncture with sham acupuncture, conventional medications, or other forms of treatment, evaluating outcomes such as treatment response rate, headache intensity, frequency of episodes, and duration of symptoms.

The results revealed concerning aspects regarding the quality of scientific research in this area. All eight systematic reviews analyzed were classified as having "critically low" methodological quality according to AMSTAR-2 criteria. The main problems identified included the absence of pre-established research protocols, lack of comprehensive search strategies, absence of lists of excluded studies with justifications, and inadequate consideration of the risk of bias of the original studies in the interpretation of results. When the researchers analyzed the quality of the evidence using the GRADE system, they found that of the 36 outcome measures evaluated in the reviews, 69.4% provided low- or very-low-quality evidence, only 11.1% offered moderate-quality evidence, and 19.4% presented high-quality evidence.

Despite these methodological limitations, the descriptive analysis of the results suggested that acupuncture may be effective in reducing both the frequency and intensity of tension-type headaches.

For patients suffering from tension-type headache, these results suggest that acupuncture may be a beneficial therapeutic option, especially considering that it is generally safe and can be used in conjunction with other forms of treatment. However, it is important for patients and healthcare professionals to understand that current scientific evidence still has significant limitations. The low methodological quality of the studies means that the results may not accurately reflect the true efficacy of acupuncture, and higher-quality studies are needed to confirm these benefits. For healthcare professionals, especially acupuncturists and neurologists, this study highlights the need to interpret the current scientific literature with caution and emphasizes the importance of conducting future research with greater methodological rigor.

Furthermore, the results suggest that acupuncture may be considered as part of an integrated therapeutic approach, especially in cases where conventional treatments do not provide adequate relief.

The study has several important limitations that should be considered. The assessment of methodological quality and evidence is a subjective process, and different researchers may reach slightly different conclusions. In addition, many of the studies analyzed were published before the creation of the most recent assessment tools, which may have negatively influenced their quality scores. The researchers also noted that the implementation of blinded studies in acupuncture research is particularly challenging due to the nature of the intervention, which may contribute to the risk of bias.

Despite these limitations, this work provides a comprehensive assessment of the current state of scientific evidence on acupuncture for tension-type headache. The authors conclude that although acupuncture appears to be an effective treatment modality for this condition, the credibility of the results is limited by the generally low methodological quality of the available studies. They emphasize that future research should follow more rigorous methodological standards to provide more reliable evidence on the efficacy of acupuncture in the treatment of tension-type headache, benefiting both patients and healthcare professionals in making more informed therapeutic decisions.