Genetic and Phenotypic Profiling of Triptan Users in a Swedish Cluster Headache Cohort.

ABSTRACT

Up to 25% of individuals who live with cluster headache (CH), an extremely painful primary headache disorder, do not adequately respond to the first-line treatment, triptans. Studies have indicated that genetic variants can play a role in treatment response. Likewise, differences in clinical characteristics can give clues to mechanisms underlying triptan non-response. Our aim was to investigate five genetic variants previously implicated in triptan response and their relation to triptan usage in our Swedish CH cohort and to investigate potential distinctions in clinical characteristics. 545 CH patients were screened for the genetic variants rs1024905, rs6724624, rs4795541, rs5443, and rs2651899 with a case control design based on triptan usage. Analysis of clinical characteristics was based on self-reported questionnaire data from 893 patients. One genetic variant, rs1024905, was significantly associated with triptan non-usage in CH (Pc = 0.010). In addition, multi-allele effector analysis showed that individuals with a higher number of effector variants were less likely to use triptans (P = 0.007). Analysis of clinical characteristics showed that triptan users were more likely to have alcohol as a trigger (57.4% vs 43.4%, P = 0.002), have autonomic symptoms (95.1% vs 88.1%, P = 0.002), and be current smokers (27.0% vs 21.9%, P = 0.033) compared to non-users. These results support the hypothesis that genetic variants can play a role in triptan usage in CH and that patients with a typical CH phenotype are more likely to use triptans.