Self-Reported Efficacy of Treatments in Cluster Headache: a Systematic Review of Survey Studies

Abstract

Purpose of review: The use and efficacy of various substances in the treatment of CH have been studied in several retrospective surveys. The aim of the study is to systematically review published survey studies to evaluate the reported efficacies of both established and unconventional substances in abortive and prophylactic treatment of both episodic and chronic CH, specifically assessing the consistency of the results.

Recent findings: No systematic review have been conducted of these studies previously. A systematic literature search with a set of search terms was conducted on PubMed. Retrospective surveys that quantified the self-reported efficacy of two or more CH treatments, published in English during 2000-2020, were included. Several key characteristics and results of the studies were extracted. A total of 994 articles were identified of which 9 were found to be eligible based on the selection criteria. In total, 5419 respondents were included. Oxygen and subcutaneous triptan injections were most reported as effective abortive treatments, while psilocybin and lysergic acid diethylamide were most commonly reported as effective prophylactic treatments. The reported efficacy of most substances was consistent across different studies, and there were marked differences in the reported efficacies of different substances. The reported order of efficacy is generally in agreement with clinical studies. The findings suggest that retrospective surveys can be used to obtain supporting information on the effects of various substances used in the treatment of CH and to form hypotheses about novel treatment methods. The consistently reported efficacy of psilocybin and LSD in prophylactic treatment indicates need for clinical studies.

Keywords: Cluster; Comparison; Efficacy; Headache; Review; Survey.

Fig. 1

PRISMA flow-diagram outlining the study selection process

Fig. 2

The combined data for the reported effectiveness of different treatments for acute CH attack abortion. The figure includes results from all 8 included surveys. The data is represented in binary scale (effective, not effective) when possible, or in a scale including partial effectiveness in case of two articles

Fig. 3

The combined data for the reported effectiveness of different treatments for acute CH attack abortion. The figure includes results from all 8 included surveys. The data is represented in binary scale (effective, not effective) when possible, or in a scale including partial effectiveness in case of two articles

Fig. 4

The hierarchical clustering of self-reported efficacy of the treatments, Spearman correlation with average linkage. Each line consists of: white marker, each indicating the place of a single treatment from a single survey. There are multiple white markers per column, one for each survey which reported on the same treatment. The blue-to-yellow gradient indicates the frequency of both the self-reported effective and self-reported not-effective responses for one treatment from one survey per line. Dark blue indicates frequency of 0%, and bright yellow indicates frequency of 100% of the participants. The columns are organized based on the hierarchical clustering algorithm and both the treatment and frequency columns are placed based on the rank correlation between the columns, as indicated by the dendrogram on the top of the figure. The exact place of the column has no meaning, the place in the dendrogram is the sole indicator for the similarity of any columns as determined by the correlation between the treatments and the frequency data