Free triiodothyronine in intracranial aneurysms: a sex-specific association with unruptured disease and a non-thyroidal illness signal after rupture.

INTRODUCTION

Thyroid dysfunction has been implicated in neurovascular pathologies, but its role in intracranial aneurysm formation and rupture is uncertain. Materials and.

METHODS

This is a retrospective single-centre case-control study of patients with unruptured (UIA) or ruptured intracranial aneurysms (RIA) and aneurysm-free controls. Low free triiodothyronine (fT3) was defined as below 3.5 pmol/L. Multivariable logistic regression was adjusted for age, sex, hypertension, alcohol abuse, and smoking.

RESULTS

The cohort comprised 1,100 patients (60.0% female), including UIA (n = 213), RIA (n = 629), and controls (CTRL, n = 258). Low fT3 was observed in 58.8% of RIA patients (p < 0.001). In multivariable logistic regression analysis including age, sex, hypertension, alcohol abuse, and smoking, female sex (OR 4.90; 95% CI 2.70-8.92) and low fT3 (OR 3.05; 95% CI 1.28-7.28) were independently associated with UIA. Low fT3 was less frequent in UIA (3.8%) than in CTRL (14.0%) but was independently associated with UIA after risk-factor adjustment. Low fT3 was strongly associated with ruptured-aneurysm status (OR 38.0; 95% CI 15.90-90.89), a contrast likely driven by acute non-thyroidal illness syndrome after haemorrhage rather than a rupture-risk estimate. The fT3-UIA association was sex-dependent (interaction p = 0.030; females OR 2.43, p = 0.003; males OR 1.02, p = 0.938).

DISCUSSION AND

CONCLUSION

Reduced fT3 in RIA may partly reflect impaired peripheral conversion after haemorrhage, but low fT3 was also independently associated with aneurysm presence in females. Low fT3 may be a candidate endocrine marker associated with aneurysm presence. Whether thyroid optimisation influences aneurysm development remains to be tested in prospective studies.