The study employs a retrospective analysis utilizing existing electronic medical records (EMRs) from ED at Guangdong Provincial Hospital of Chinese Medicine (GPHCM), which is the largest tertiary hospital that provides integrated Chinese medicine and conventional therapies for patients in China (19). The study was approved by the Human Research Ethics Committee of GPHCM with a waiver of consent (BE2024-188-01).

The EMRs with a first diagnosis of headache between 1 January 2023 and 31 December 2023 from four EDs at GPHCM were identified and retrieved by the Information Technology Department of GPHCM. The diagnosis of headache could either be general, without specifying the type or cause (as doctors may prioritize capturing the most prominent complaint, ‘headache,’ as a diagnosis), or it could be a specific type of headache such as migraine, tension-type headache, or cluster headache. EMRs with incomplete information would be excluded for further screening.

Structured data, such as triage category, age, gender, primary diagnoses and concurrent diagnoses, treatment methods, results of brain imaging including head computed tomography (CT) and magnetic resonance imaging (MRI), medicines and herbs were extracted by Zhenhui Mao and double checked by Shaohua Lyu. It should be noted that detailed headache variables like duration of headache, previous medication history for headache episodes, associated symptoms of headache and severity of headache were not consistently available in the EMRs. In addition, doses of herbs varied among patients according to individual conditions, therefore doses of herbs were not extracted or analyzed.

Chinese medicinal herbs in different forms (granule or decoction piece) or being processed in various ways were standardized as one herb name as they share similar functions, in accordance to the World Flora Oline Plant List (20). For example, zhi gan cao (fried gan cao) was standardized as gan cao (Glycyrrhizae Radix et Rhizoma) since they were not distinguished in function. Conversely, the function of gan jiang (dried ginger, Zingiberis Rhizoma) is distinguished from that of sheng jiang (fresh ginger, Zingiberis Rhizoma Recens) according to the China Pharmacopoeia (version 2020) (21), therefore they were counted separately.

IBS SPSS statistics (version 26.0, IBM Corp., Armonk, NY, United States) was employed for descriptive analyses (22). Quantitative variables were described as mean with standard deviation and compared using Student’s t-test when appropriate. While categorical variables were presented as counts and percentages and compared by Chi square test, where feasible.

Association rule construction based on the Apriori algorithm (23, 24) was conducted to identify high-frequency herb combinations, using SPSS Modeler software (version 18.0, SPSS Inc., Chicago, IL, United States).

A total of 3,355 patients attending EDs for headaches at GPHCM throughout the year 2023 were included in this study. Patients’ characteristics were presented in Table 1. Female patients constituted approximately 65% of the population and were older than male patients (48.62 years vs. 43.83 years, p < 0.001).

Among the patients, only 8.46% of them were diagnosed with a primary headache, like migraine, tension-type and cluster headache. Up to 97.14% of the patients were roughly diagnosed with headaches without specific classification as their first diagnoses.

During the procedure of diagnoses, brain imaging (CT or MRI) was carried out among 66.26% of the patients, where head CT was run out for 63.79% of all headache patients and identified 0.98% of the ED patients as subarachnoid hemorrhage or intracranial hemorrhage.

In terms of concomitant diagnoses, hypertension ranked as the most common concurrent condition among 27.42% (n = 920) of the ED attendances, followed by coronary atherosclerotic heart disease among 8.67% of the headache patients.

A four-tier triage scale was utilized in EDs to sort or prioritize the ED attendances (25, 26). Only 1.04% of the patients were categorized into life-threatening or emergent emergencies, while up to 86.20% of the patients were justified as nonurgent conditions.

In ED settings, western medicine stood as the most popular treatment method among 2,227 (66.38%) patients, followed by PCHMPs (n = 1,749, 52.13%), and oral CHM decoction (n = 1,031, 30.73%). Other treatments included Chinese herbal injection, topical application of CHM, acupuncture, and ear acupressure (Table 1).

In addition, 1,670 patients were prescribed WM in combination with CHM decoctions or PCHMPs, 557 patients utilized WM alone, while 1,128 received Chinese medicine therapies without any WM.

The study described characteristics of 3,355 ED attendances with headaches from four branches of a tertiary Chinese medicine hospital and summarized the regularity of Chinese medicine for headaches. The results of our study provide real-world clinicians’ experience of prescribing Chinese medicine for acute headaches, which can contribute to evidence-based medical decision-making for headaches in clinical practice and health policy making, along with other components such as clinical research evidence and patients’ preferences and values (27).

According to the results, females took a larger percentage over males, and these female patients aged elder than male patients. A previous study a reported a similar finding (28). This female predominance may be due to the fact that females are more susceptible to headaches, particularly migraines, which can be attributed to hormonal fluctuations (29, 30).

Similar to previous reports, the study again found that most headaches are benign (8, 31), as 86.20% of the patients were classified as less urgent or nonurgent according to the triage category (25, 26). However, headaches can also be secondary to serious and life-threatening conditions like hemorrhages and brain tumors. It is critical to recognize, evaluate, and appropriately manage these dangerous secondary headaches in prevention of potential long-term disability or death (31). Brain images were excessively scanned among headache patients (32–34). However, brain imaging was not recommended as a routine practice for uncomplicated headaches in USA (35). Indications for neuroimaging should be strongly based on the patient’s clinical history and a detailed physical examination (2, 36). It is critical to recognize the red flags of a secondary headache: systemic signs, neurological symptoms, sudden onset, older age at onset, progression, papilledema, positional or precipitated by Valsalva and pregnancy, in order to save unnecessary examinations and detect early signs of life-threatening conditions (37–40).

In addition, most of the diagnoses included in this study were categorized as general headaches without further precise classifications. Non-specific diagnoses were prevalent in EDs (41). However, it is hypothesized that the lack of specificity in these diagnoses may not meet the requirements of precision medicine.

The study involved a diverse range of western medications. Overall, western medicine was prescribed to two-thirds of the ED patients. However, in terms of acute medications, only one-tenth of the ED patients received NSAIDs or tramadol, which is relatively limited compared to the higher use of acute medications in other countries (32, 34). Conversely, headache-specific PCHMPs based on Chinese Pharmacopeia (21), such as Tian shu tablets, Gastrodin injection, and Tong tian oral solution, etc., were prescribed to over one-third of the headache patients. Studies have demonstrated their anti-headache, particular anti-migraine effects, from bench to bedside (42–47). Moreover, they have been recommended in clinical guideline for headaches (48).

Additionally, tailored CHM decoctions were prescribed for acute headaches in EDs, with core herb combinations being ingredients of CXCTS. CXCTS has been widely used for headaches since ancient times and is included in headache clinical guidelines (18, 48, 49). Meta-analyses of randomized controlled trials have shown that CXCTS can significantly improve headache frequency and duration, alone or in combination with western medicine (50, 51), through regulating neurotransmitter transmission, inflammation, angiogenesis, vasomotor, immunity and other pathways (52).

In addition to oral CHM treatment, topical applications of CHM have been introduced since ancient times, yet they are seldom utilized in contemporary outpatient departments (18, 53). It is noteworthy that CHM was applied topically to headache patients in EDs. However, unlike the intranasal method described in classical literature, the application of CHM patches on acupuncture points or focal areas of the headache is more prevalent in modern clinical practice (53). Additionally, the herbs commonly used in patches, such as jie zi, lai fu zi and zi su zi, differ significantly from those used intranasally in classical texts (53). Both laboratory and clinical evidence are necessary to support the use of topical CHM for headaches.

Based on the comparative use of acute medications and Chinese medicine in this study, we hypothesize that various forms of CHM therapies might serve as complementary and alternative methods to acute medications, potentially reducing acute medication usage and the risk of medication overuse (54). However, the hypothesis needs further verification in future clinical efficacy trials.

Some inevitable limitations were identified in this study. Firstly, being a retrospective study, the study did not include quantitative assessment of the treatment effects of CHM for acute headaches in EDs. Secondly, subgroup treatment analyses based on diagnoses were not feasible as most of the diagnoses were not specifically verified. Thirdly, the study was conducted solely in four branches of a Chinese medicine hospital located in southern China, limiting the generalizability of the results due to potential geographic differences.