Comparison of 2 approaches for determining the natural history risk of brain arteriovenous malformation rupture

Document Type

Article

Abstract

Estimating risk of intracranial hemorrhage (ICH) for patients with unruptured brain arteriovenous malformations (AVMs) in the natural course is essential for assessing risks and benefits of treatment. Traditionally, the survival period starts at the time of diagnosis and ends at ICH, but most patients are quickly censored because of treatment. Alternatively, a survival period from birth to first ICH, censoring at the date of diagnosis, has been proposed. The authors quantitatively compared these 2 timelines using survival analysis in 1,581 Northern California brain AVM patients (2000-2007). Time-shift analysis of the birth-to-diagnosis timeline and maximum pseudolikelihood identified the point at which the 2 survival curves overlapped; the 95% confidence interval was determined using bootstrapping. Annual ICH rates per 100 patient-years were similar for both the birth-to-diagnosis (1.27, 95% confidence interval (CI): 1.18, 1.36) and the diagnosis-to-ICH (1.17, 95% CI: 0.89, 1.53) timelines, despite differences in curve morphology. Shifting the birth-to-diagnosis timeline an optimal amount (10.3 years, 95% CI: 3.3, 17.4) resulted in similar ICH survival curves (P = 0.979). These results suggest that the unconventional birth-to-diagnosis approach can be used to analyze risk factors for natural history risk in unruptured brain AVM patients, providing greater statistical power. The data also suggest a biologic change around age 10 years influencing ICH rate. © 2010 The Author.

Publication Date

6-11-2010

Publication Title

American Journal of Epidemiology

ISSN

00029262

E-ISSN

14766256

Volume

171

Issue

12

First Page

1317

Last Page

1322

PubMed ID

20472570

Digital Object Identifier (DOI)

10.1093/aje/kwq082

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