Background: Cluster headache is the most common primary headache disorder of the trigeminal autonomic cephalalgias, and it is highly disabling.Objective: We undertake a scoping review to characterize therapies to prevent and acutely treat cluster headache, characterize trial methodology utilized in studies, and recommend future trial "good practices." We also assess homogeneity of studies and feasibility for future network meta-analyses (NMAs) to compare acute and preventive treatments for cluster headache.
Methods:A priori protocol for this scoping review was registered and available on Open Science Forum. We sought studies that enrolled adult patients with cluster headache as identified by accepted diagnostic criteria. Both randomized controlled trials (RCTs) and observational studies (with a control group) were included. The interventions of interest were medications, procedures, devices, surgeries, and behavioral/psychological interventions, whereas comparators of interest were placebo, sham, or other active treatments.Outcomes were predefined; however, we did not exclude studies lacking these outcomes.A systemic search was conducted in Ovid Medline, Embase, and Cochrane. We performed a targeted search for conference abstracts from journals prominent in the field.
Results:We identified 56 studies: 45 RCTs, four studies only available in clinical trial registries, and seven observational studies. Of the 45 RCTs, 20 focused on acute therapies and 25 on preventive therapies. Overall, we determined that it is feasible to pursue a NMA for acute therapy focusing on 15 or 30-min headache reduction for acute trials, as we identified 11 trials in the combined population of patients with either episodic or chronic cluster headache (2 trials in populations with chronic cluster headache were also found). For preventive therapy of cluster headache, we identified trials with common outcomes that may be considered for NMA, however, as these trials had differences in treatment effect modifiers that could not be corrected, NMAs appear infeasible for this indication. We identified new studies looking at noninvasive vagal nerve stimulation, sphenopalatine ganglion stimulation, prednisone, and oxygen published since the most recent systematic review in the field, although these acute treatments were previously identified as effective. However, for calcitonin gene-related
Rationale for this workThere are few evidence-based treatments available in CH, 3,4 as it is a condition that has been under studied. 1 The current scoping review was designed to expand upon past reviews in several ways. First, we sought to identify new studies published since the prior reviews were completed. 3,4 Second, with the data gathered in this scoping review, we aimed to assess the feasibility of pursuing network metaanalyses (NMAs) 5,6 to inform comparisons of multiple treatments based on available direct and indirect evidence in the field. We planned to systematically evaluate study and population features to establish the potential for rigorous N...