Reporting quality and evidence support in randomized controlled trials of herbal medicine formulas for vestibular...

Vestibular migraine (VM) is a prevalent condition characterized by recurrent episodes of dizziness, vertigo, and/or headache, often posing diagnostic and therapeutic challenges. Numerous randomized controlled trials (RCTs) have highlighted potential benefits of herbal medicine formulas (HMFs) for treating VM. However, current evidence remains insufficient to recommend their routine clinical use. The validity of trial results relies heavily on the completeness of the reporting. Therefore, this study aimed to comprehensively evaluate the reporting quality and evidence support of RCTs investigating HMFs for VM.

We performed a comprehensive search across eight databases from their inception to August 2024. The included studies were primarily RCTs assessing the effectiveness and safety of HMFs for treating VM. The quality of the RCTs was evaluated using the Consolidated Standards of Reporting Trials (CONSORT) guidelines, along with its extension for Chinese medicine formulas (CONSORT-CHM Formulas). A meta-analysis was conducted to assess the effectiveness and safety of HMFs for the treatment of VM following the Cochrane methodolog. High-frequency herbal medicines (HMs) for VM treatment were identified as those appearing with a cumulative frequency exceeding 50 % among the top-ranked HMs.

A total of 33 RCTs involving 2358 patients with VM were included. The mean score for CONSORT reporting items was 14.24, while the mean score for CONSORT-CHM reporting items was 13.64. Few trials adequately reported essential elements such as appropriate titles, sample size calculations, allocation concealment, randomization implementation, and descriptions of blinding within the CONSORT core items. For CONSORT-CHM, less than half of the studies specified the formula names, dosage forms, and targeted traditional Chinese medicine (TCM) patterns in their titles and abstracts. Most studies demonstrated a high risk of bias, particularly regarding randomization sequence generation, allocation concealment, and blinding. The meta-analysis indicates that HMFs are effective in treating VM with minimal adverse effects; however, the high heterogeneity in certain outcomes suggests a potential risk of bias. The five most frequently used herbs across all studies were, in descending order: Gastrodiae Rhizoma, Rhizoma Pinelliae, Rhizoma Chuanxiong, Poria, Atractylodis Macrocephalae Rhizoma.

The meta-analysis supports the effectiveness and safety of HMFs for treating VM, with a low incidence of adverse events. However, the CONSORT and CONSORT-CHM reporting items were underreported. Future RCTs should strictly adhere to these guidelines to enhance reporting quality, ensuring full transparency in study design and methodolog. This study contributes to a more rigorous evidence base for HMFs in VM treatment. It aims to improve the quality of future RCTs involving herbal formulas for VM, enabling clinicians to make better-informed decisions.