Impact of thyroid hormone replacement therapy on the course and functional outcome of aneurysmal subarachnoid hemorrhage.

109 of 995 aneurysmal SAH patients (11%) were on thyroid hormone replacement therapy (THRT) prior to SAH.

• Study included SAH individuals treated between January 2003 and June 2016.
• Total cohort consisted of 995 individuals.
• 109 patients (11%) had THRT before SAH due to pre-existing hypothyroidism.
• Data recorded included baseline characteristics, adverse events, and functional outcome.

Presence of THRT was inversely associated with risk of intracranial pressure- or vasospasm-related cerebrovascular events.

• The association between THRT and reduced cerebrovascular events was statistically significant (p = 0.047).
• Events considered included both intracranial pressure-related and vasospasm-related cerebrovascular events.
• This finding suggests a protective effect of THRT on ischemia-relevant complications following SAH.

THRT was independently associated with a lower risk of cerebral infarction in multivariate analysis.

• Adjusted odds ratio (aOR) for cerebral infarction was 0.64 (95% CI = 0.41–0.99, p = 0.045).
• The association was adjusted for outcome-relevant confounders.
• This represents a approximately 36% reduction in the odds of cerebral infarction for THRT patients.

THRT was independently associated with a lower risk of unfavorable outcome at 6 months in multivariate analysis.

• Adjusted odds ratio (aOR) for unfavorable outcome was 0.50 (95% CI = 0.28–0.89, p = 0.018).
• This represents approximately a 50% reduction in the odds of unfavorable outcome for THRT patients.
• The association was adjusted for outcome-relevant confounders.
• Functional outcome was assessed at 6 months post-SAH.

THRT was not independently associated with in-hospital mortality in multivariate analysis.

• Adjusted odds ratio (aOR) for in-hospital mortality was 0.69 (95% CI = 0.38–1.26, p = 0.227).
• The result did not reach statistical significance (p = 0.227).
• In-hospital mortality was one of three pre-specified study endpoints.