title: Subarachnoid hemorrhage in type 1 diabetes: a prospective cohort study of 4,083 patients with diabetes.
abstract: OBJECTIVE
  To estimate for the first time the incidence of subarachnoid hemorrhage (SAH) in type 1 diabetes.
  
  
  METHODS
  Using the nationwide Finnish Diabetic Nephropathy (FinnDiane) Study cohort of 4,083 patients with type 1 diabetes (mean age of 37.4 ± 11.8 years at enrollment), we analyzed the incidence of first-ever SAH events.
  
  
  RESULTS
  During the follow-up time of 36,680 person-years (median 9.4 years), 15 patients with type 1 diabetes experienced an aneurysmal or nonaneurysmal SAH, and thus the crude incidence of SAH was 40.9 (95% CI 22.9-67.4) per 100,000 person-years. One patient had a verified aneurysmal SAH, and four patients died suddenly of an SAH, which was most likely caused by an aneurysm. SAHs in 10 out of 15 patients were classified as nonaneurysmal SAH, and thus the crude incidence of nonaneurysmal SAH was 27.3 (13.1-50.1) per 100,000 person-years. None of the nonaneurysmal SAHs were fatal. In univariate analysis, current smokers had a hazard ratio of 4.82 (95% CI 1.31-17.81) for nonaneurysmal SAH.
  
  
  CONCLUSIONS
  The incidence of nonaneurysmal SAH is high among patients with type 1 diabetes. Our findings suggest that nonaneurysmal SAH is a distinct new microvascular complication in type 1 diabetes.
authors.affiliation: Corresponding authors: Miikka Korja, mkorja@mqneurosurgery.com.
authors.forename: Miikka
authors.initials: M
authors.lastname: Korja
authors.forename: Lena M
authors.initials: LM
authors.lastname: Thorn
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hägg
authors.forename: Jukka
authors.initials: J
authors.lastname: Putaala
authors.forename: Ron
authors.initials: R
authors.lastname: Liebkind
authors.forename: Valma
authors.initials: V
authors.lastname: Harjutsalo
authors.forename: Carol M
authors.initials: CM
authors.lastname: Forsblom
authors.forename: Daniel
authors.initials: D
authors.lastname: Gordin
authors.forename: Turgut
authors.initials: T
authors.lastname: Tatlisumak
authors.forename: Per-Henrik
authors.initials: PH
authors.lastname: Groop
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013345:Subarachnoid Hemorrhage / Q000453:epidemiology*