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Case-fatality and functional outcome after subarachnoid hemorrhage (SAH) in INternational STRoke oUtComes sTudy (INSTRUCT)

journal contribution
posted on 2023-05-21, 09:04 authored by Sabah RehmanSabah Rehman, Hoang PhanHoang Phan, Reeves, MJ, Thrift, AG, Cadilhac, DA, Sturm, J, Monique BreslinMonique Breslin, Michele CallisayaMichele Callisaya, Vemmos, K, Parmar, P, Krishnamurthi, RV, Barker-Collo, S, Feigin, V, Chausson, N, Olindo, S, Cabral, NL, Carolei, A, Marini, C, Degan, D, Sacco, S, Correia, M, Appelros, P, Korv, J, Vibo, R, Minelli, C, Sposato, L, Pandian, JD, Kaur, P, Azarpazhooh, MR, Morovatdar, N, Seana GallSeana Gall

Background: There are few large population-based studies of outcomes after subarachnoid hemorrhage (SAH) than other stroke types.

Methods: We pooled data from 13 population-based stroke incidence studies (10 studies from the INternational STRroke oUtComes sTudy (INSTRUCT) and 3 new studies; N=657). Primary outcomes were case-fatality and functional outcome (modified Rankin scale score 3-5 [poor] vs. 0-2 [good]). Harmonized patient-level factors included age, sex, health behaviours (e.g. current smoking at baseline), comorbidities (e.g.history of hypertension), baseline stroke severity (e.g. NIHSS >7) and year of stroke. We estimated predictors of case-fatality and functional outcome using Poisson regression and generalized estimating equations using log-binomial models respectively at multiple timepoints.

Results: Case-fatality rate was 33% at 1 month, 43% at 1 year, and 47% at 5 years. Poor functional outcome was present in 27% of survivors at 1 month and 15% at 1 year. In multivariable analysis, predictors of death at 1-month were age (per decade increase MRR 1.14 [1.07-1.22]) and SAH severity (MRR 1.87 [1.50-2.33]); at 1 year were age (MRR 1.53 [1.34-1.56]), current smoking (MRR 1.82 [1.20-2.72]) and SAH severity (MRR 3.00 [2.06-4.33]) and; at 5 years were age (MRR 1.63 [1.45-1.84]), current smoking (MRR 2.29 [1.54-3.46]) and severity of SAH (MRR 2.10 [1.44-3.05]). Predictors of poor functional outcome at 1 month were age (per decade increase RR 1.32 [1.11-1.56]) and SAH severity (RR 1.85 [1.06-3.23]), and SAH severity (RR 7.09 [3.17-15.85]) at 1 year.

Conclusion: Although age is a non-modifiable risk factor for poor outcomes after SAH, however, severity of SAH and smoking are potential targets to improve the outcomes.


Publication title

Journal of Stroke and Cerebrovascular Diseases



Article number









Menzies Institute for Medical Research


Elsevier Inc.

Place of publication

United States

Rights statement

Copyright 2021 Elsevier Inc.

Repository Status

  • Restricted

Socio-economic Objectives

Evaluation of health outcomes