Duration and characteristics of persistent headache following aneurysmal subarachnoid hemorrhage

To assess the long-term frequency, prognosis, and phenotype of persistent headache following aneurysmal subarachnoid hemorrhage (aSAH).

Very little is known about long-term headache following aSAH with no studies looking beyond 3 years.

Retrospective analysis comparing aSAH cases to matched controls in the UK Biobank, a prospective cohort study. Headache frequency and phenotype were compared using group comparison tests. The relationship between headache frequency and time was assessed using correlation analysis.

Headache was more frequent following aSAH (aSAH: 258/864 [29.9%] vs. controls: 666/3456 [19.3%], χ²  = 45.5, p < 0.001) at a median follow-up of 7.5 years. Headache frequency decreased over time (R_S  = -0.71, p = 0.028), affecting 29/58 (50%) patients in the first year and reducing to 13/47 (28%) patients 10 years later. Headache frequency was not related to aSAH severity (z = 0.249, p = 0.803), treatment (z = 0.583, p = 0.560), or hydrocephalus (z = -1.244, p = 0.214). There was a consistently higher frequency of migrainous features following aSAH compared to controls, although this did not reach statistical significance.

Persistent headache is more frequent following aSAH compared to controls in the long term and the prevalence reduces gradually over time. The increased frequency of migrainous features suggests that selected patients with post-aSAH headache may benefit from migraine treatment.