Acupuncture and related therapies for tension-type headache: a systematic review and network meta-analysis

Tension-type headache is one of the most common neurological problems in the world, affecting between 30% and 78% of the population across different cultures and regions. Characterized by bilateral, pressure-like or tightening pain in the head, often accompanied by sensitivity to light and sound, this condition can progress from episodic to chronic when not properly treated. Conventional treatment is primarily based on simple analgesics and anti-inflammatory medications for acute episodes, while tricyclic antidepressants are used for the prevention of the chronic form. However, the frequent use of these medications can cause significant gastrointestinal side effects, sparking interest in complementary therapies such as acupuncture, which has demonstrated efficacy in pain control through multiple neurobiological mechanisms.

This study aimed to compare the effectiveness and safety of different acupuncture modalities in the treatment of tension-type headache through a systematic review and network meta-analysis. The researchers carried out comprehensive searches in nine databases up to December 2022, including PubMed, Cochrane Library, Web of Science, EMBASE, and Chinese databases, following rigorous protocols registered with PROSPERO. Randomized clinical trials were included that compared different acupuncture techniques, such as conventional acupuncture, electroacupuncture, scalp acupuncture, therapeutic bloodletting, and plum-blossom needling, used alone or in combination with Western medications or herbal medicine. The main outcomes analyzed were overall effectiveness rate, visual analog scale of pain, frequency of headache attacks, and adverse events.

The statistical analysis involved traditional direct meta-analyses followed by Bayesian network meta-analysis, allowing for indirect comparisons between treatments that were not directly compared in the original studies.

The analysis included 30 randomized clinical trials with 2,722 patients, all conducted in China between 2000 and 2022. The direct meta-analyses showed that conventional acupuncture was superior to Western medicine across multiple outcomes, with an odds ratio of 4.37 for improvement in general symptoms and an average reduction of 1.48 points on the pain scale compared to conventional medications. Therapeutic bloodletting proved to be even more effective than conventional acupuncture, with an odds ratio of 6.32. In the network meta-analysis, therapeutic bloodletting obtained the highest SUCRA value for overall effectiveness (0.93), indicating a 93% probability of being the best treatment for improvement of overall symptoms of tension-type headache.

For pain intensity reduction, scalp acupuncture combined with Western medicine showed the best performance (SUCRA = 0.90), while acupuncture combined with herbal medicine showed a trend toward greater efficacy in reducing attack frequency, although without statistical significance. Safety was satisfactory, with only three studies reporting mild adverse events, mainly nausea, vomiting, and local allergic reactions, with incidence ranging from 3% to 19%.

The clinical implications of these findings are promising for patients and professionals seeking safe alternatives to conventional medications. Therapeutic bloodletting emerges as a particularly effective option for overall symptom improvement, working through stimulation of local nerves and activation of central nuclei that regulate vasoconstriction. Scalp acupuncture combined with Western medications may represent an optimized integrative approach for pain control, possibly enhancing analgesic mechanisms through the release of endogenous opioids and modulation of serotonergic and dopaminergic neurotransmission. For patients with frequent attacks, the combination of acupuncture with herbal medicine offers a completely natural alternative, although the results require confirmation in larger studies.

The favorable safety profile of acupuncture is especially relevant for patients who develop intolerance to conventional medications or who prefer to avoid the risks of chronic use of analgesics and anti-inflammatories.

The study has important limitations that should be considered when interpreting the results. The methodological quality of the included trials was variable, with many studies presenting an unclear risk of bias due to a lack of detail on randomization, allocation concealment, and blinding. All studies were conducted in China, limiting the generalizability of the findings to other populations and cultures. Clinical heterogeneity was considerable, with variations in the acupuncture points used, depth and duration of sessions, as well as a lack of specific classification of tension-type headache subtypes.

Most studies did not include long-term follow-up, making it impossible to assess sustained efficacy. In addition, only three studies systematically reported adverse events, limiting the quantitative analysis of safety. Future studies should follow rigorous guidelines such as STRICTA, include more diverse populations, standardize treatment protocols, and incorporate prolonged follow-up assessments to definitively establish the role of acupuncture in the management of tension-type headache.