Bloodletting therapy for treating patients with chronic urticaria: A systematic review and meta-analysis protocol.

Background: Chronic urticaria is a common disease affecting patients' quality of life, and leading to substantial burden to both patients and society. Many trials have shown that bloodletting therapy is effective in treating chronic urticaria. There are currently no systematic reviews of bloodletting therapy for chronic urticaria. This protocol aims to present the methods used to assess the effectiveness and safety of bloodletting therapy for patients with chronic urticaria. Methods: The following databases will be searched from their inception: the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), Chinese Scientific Journal Database (VIP database), and Wan-Fang Database. Clinical randomised controlled trials related to bloodletting therapy for treating chronic urticaria will be included, regardless of publication status and languages. Study selection, data collection, and quality assessment will be independently conducted by 2 researchers. For data synthesis, we will select either the fixed-effects or random-effects model according to heterogeneity assessment. Disease activity control will be assessed as the primary outcomes. Response rate, recurrence rate and adverse events will be evaluated as secondary outcomes. If it is appropriate for meta-analysis, RevMan V.5.3 statistical software will be used. Otherwise, a systematic narrative synthesis will be conducted. The results will be presented as risk ratio (RR) with 95% confidence intervals (CIs) for dichotomous data and weight mean difference (WMD) or standard mean difference (SMD) 95% CIs for continuous data. Dissemination and ethics: The protocol of this systematic review will be disseminated in a peer-reviewed journal and presented at relevant conferences. It is not necessary for a formal ethical approval because the data are not individualised.