The Effectiveness of Acupuncture on Headache Intensity and Frequency in Patients With Tension-Type Headache: A Systematic Review and Meta-Analysis

Tension-type headache is considered the most common form of primary headache in adults, significantly affecting patients' quality of life and generating high economic costs for society. Characterized by pain or discomfort in the head region that may radiate to the neck, this condition is frequently related to myofascial trigger points in the muscles of the head and neck, in addition to complex neurological mechanisms involving both peripheral and central nervous system factors. Although various therapeutic approaches are used in treatment, including analgesic medications, physical therapy, and relaxation techniques, acupuncture has gained growing popularity among patients seeking therapeutic alternatives, despite the lack of robust scientific evidence on its efficacy.

This study aimed to scientifically evaluate the effectiveness of acupuncture in the treatment of tension-type headache, specifically analyzing its impact on the intensity and frequency of headache attacks. The researchers conducted a rigorous systematic review of the scientific literature, following established international protocols. The search was performed in four major medical databases between January 2000 and February 2021, initially identifying more than 2,000 scientific articles. After applying rigorous selection criteria, only 15 studies of high methodological quality were included in the analysis, totaling 1,272 participants.

Of these, only four studies with 557 participants met the specific criteria for the statistical meta-analysis, which is a method that combines results from multiple studies to obtain more reliable conclusions. The selected studies compared different types of acupuncture with simulated treatments or other interventions, evaluating both immediate results after the end of treatment and long-term effects.

The meta-analysis results revealed important findings, but also some limitations in the efficacy of acupuncture. In the period immediately after the end of treatment, acupuncture did not demonstrate statistically significant superiority over control groups in reducing the frequency of headache attacks. The mean difference observed was a reduction of approximately 1.5 headache days per month, but this result did not reach statistical significance. Similarly, pain intensity, measured through visual analog scales, showed only a small immediate improvement that was not statistically significant.

However, when the researchers analyzed long-term effects, they found more promising results. After an average follow-up period of two months, acupuncture demonstrated statistically significant benefit in reducing pain intensity, with a mean decrease of 0.41 points on the pain scale. Although a reduction in attack frequency was also observed in the long term, this result was at the borderline of statistical significance.

For patients suffering from tension-type headache, these findings suggest that acupuncture may offer benefits, especially when long-term effects are considered. The significant improvement in pain intensity after a few months may represent important relief for those living with chronic headaches. It is important to note that acupuncture demonstrated greater efficacy when combined with other therapies, such as physical therapy or specific exercises, suggesting that an integrated approach may be more beneficial than treatment in isolation. For health professionals, these results indicate that acupuncture can be considered as part of a comprehensive therapeutic plan, especially for patients seeking alternatives to conventional medications or who do not respond adequately to other treatments.

The dry needling technique, a modality related to acupuncture, showed more consistent results in the analyzed studies, suggesting that different needle stimulation techniques may have distinct efficacies.

The study presents some important limitations that should be considered in the interpretation of the results. The relatively small number of studies eligible for meta-analysis and the small sample sizes in many of the individual studies may have limited the ability to detect statistically significant differences between groups. In addition, the heterogeneity of acupuncture protocols used in the different studies, including variations in application points, frequency, and duration of treatment, may have influenced the results. The inherent difficulty in creating truly blinded control groups in acupuncture studies also represents a methodological challenge, since both patients and therapists can often identify whether the treatment is real or simulated.

The authors acknowledge that future studies with larger samples and more standardized protocols are needed to confirm and expand these findings, particularly with respect to effects on the frequency of headache attacks, where the results remained inconclusive.