204 Idiopathic intracranial hypertension in Wales: population characterisation, epidemiological trends and healthcare utilisation

Objective To characterise the Welsh idiopathic intracranial hypertension (IIH) population, epidemiologi- cal trends and healthcare outcomes using routinely collected healthcare data. Methods We used primary and secondary care healthcare diagnostic codes within the Secure Anonymised Information Linkage databank to ascertain IIH cases and controls in a retrospective cohort study between 2003–2017. We validated IIH diagnosis codes using anonymised secondary care lists of IIH cases. Results We analysed 35 million patient years of data (2003–2017). There were 1765 cases of IIH in 2017 (85% female). The prevalence and incidence of IIH in 2017 was 76/100,000 and 7.8/100,000, significantly increased from 2003 (prevalence=12/100,000, incidence=2.3/100,000). IIH prevalence is associated with socio-economic deprivation and increasing body mass index (BMI). 9% of people with IIH had CSF shunts with less than 0.2% having bariatric surgery. Unscheduled hospital admissions were significantly higher in the IIH cohort compared to controls; and also in IIH patients with CSF shunts compared to those without. Conclusions IIH incidence and prevalence is increasing significantly, corresponding to population increases in BMI. This has important implications for healthcare professionals and policy makers given the comor- bidities, complications and increased healthcare utilisation and economic burden associated with IIH. lotif_miah@hotmail.com