The idiopathic intracranial hypertension prospective cohort study: evaluation of prognostic factors and outcomes

Abstract text (incl. figure legends and references)

Question

There is limited longitudinal data evaluating visual and headache outcomes in Idiopathic intracranial hypertension (IIH). We aimed to evaluate the long-term outcomes in a large prospective real-world cohort of patients with IIH and prognostic factors.

Methods

A longitudinal clinical examination dataset was analysed from the prospectively collected IIH:Life database 2012-2021. Data included demographics and disease status. Visual outcomes included visual acuity (LogMAR), perimetric mean deviation (MD) (Humphrey 24–2 central threshold) and papilloedema (optical coherence tomography (OCT) imaging measurements). Headache frequency (days per month) and the headache impact test-6 questionnaire (HIT-6) were noted. We analysed the key variables for prognostic outcomes of vision and headache, focusing on the medically treated cohort.

Results

490 had a confirmed diagnosis of IIH. 98% were female with a mean body mass index (BMI) of 38 kg/m2. Those with the highest OCT RNFL had the worst visual outcomes, but there was a delay of over 12 months before the visual field and OCT measurements revealed this decline. In the medically managed cohort (n=426) visual outcomes were good. Regression analyses showed change in BMI and disease duration had the most influence on vision.

Those who were managed medically and had active IIH (n=281) there was a high headache burden and risk of high headache frequency was found to be associated with a personal migraine history and daily headache at diagnosis. There was a low relapse rate of 3.7%, which was associated with weight gain.

Conclusions

Those with the most elevation of their RNFL had worse long-term visual outcomes which only became apparent in longer term follow-up after 12 months. In a medically managed cohort of people with IIH disease duration and change in BMI were the key factors in influencing visual outcomes. The headache burden was high, and targeted therapy remained an unmet clinical need.