Durable effects of acupuncture for tension-type headache: A systematic review and meta-analysis

Tension-type headache is the most common type of primary headache in the world, affecting approximately 26% of the global population. This condition is characterized by recurrent episodes of mild to moderate headache, typically described as a sensation of pressure or tightness on both sides of the head. Unlike migraine, tension-type headache rarely presents symptoms such as nausea or extreme sensitivity to light and sound. Although it may seem less dramatic than other types of headache, frequent or chronic tension-type headache can cause significant disability, substantially reduce quality of life, and generate enormous socioeconomic costs.

Current treatment includes preventive medications such as antidepressants, but these can have considerable side effects and do not always provide lasting relief after discontinuation.

This study aimed to investigate whether acupuncture can provide durable benefits for patients with tension-type headache after the end of treatment. The investigators conducted a systematic review and meta-analysis, which is a rigorous scientific method for combining and analyzing data from multiple studies on the same topic. They searched several medical databases looking for randomized controlled clinical trials that tested the efficacy of acupuncture for tension-type headache. To be included, studies needed to have followed patients for at least three months after the end of acupuncture treatment.

The main focus was to assess the "response rate," defined as the proportion of participants who reported at least 50% reduction in monthly headache days. They also analyzed other important aspects such as pain intensity, number of headache days per month, and analgesic use.

The analysis included seven high-quality studies involving 3,221 participants with frequent or chronic tension-type headache. The results showed that acupuncture provided benefits superior to sham acupuncture (placebo) for up to six months after the end of treatment. Specifically, more patients who received true acupuncture experienced significant improvement compared with those who received placebo treatment. This difference was observed at one month (56% greater chance of improvement), three months (41% greater), and six months (36% greater) after the end of sessions.

Regarding the number of headache days per month, patients treated with acupuncture had consistent and significant reductions in most assessed periods. Pain intensity also showed durable improvements, especially between the third and sixth month after treatment. Interestingly, although there was a trend toward reduced use of analgesic medications in the acupuncture group, this difference did not reach statistical significance.

For patients suffering from frequent tension-type headache, these results suggest that acupuncture may be a valuable therapeutic option with benefits that persist well beyond the active treatment period. This is particularly important because many headache treatments only work while they are being used. Acupuncture's ability to provide durable relief may mean less dependence on medications, lower risk of headaches from analgesic overuse, and better long-term quality of life. For healthcare professionals, these findings support the inclusion of acupuncture as part of a preventive approach for tension-type headache, especially considering its favorable safety profile.

Indeed, the study found no serious adverse events related to acupuncture, with only mild and transient side effects such as small hematomas at the application site.

However, it is important to recognize the limitations of this study. The number of included studies was relatively small, and some studies had methodological problems that may have influenced the results. In addition, loss of participants during follow-up was considerable in some studies, which may have affected the reliability of the findings. The investigators also observed that there is insufficient evidence to compare the durable efficacy of acupuncture with other non-pharmacologic treatments or with preventive medications.

Another important point is that the beneficial effects, although statistically significant, were considered modest in magnitude. Therefore, although the results are promising and suggest that acupuncture may offer durable benefits for tension-type headache for up to six months after treatment, more studies with rigorous methodology, larger samples, and longer follow-up are needed to definitively confirm these findings and guide more robust clinical recommendations.