Idiopathic intracranial hypertension in the British population with obesity

Idiopathic intracranial hypertension (IIH) is a syndrome that is characterized by persistently high intracranial pressure and associated with high rates of morbidity and visual loss. Its exact etiology and clinical picture is poorly understood, but it is known to be associated with obesity. The aim of this study was to investigate the prevalence and clinical manifestations of IIH using a large nationwide database of British subjects.

The anonymized healthcare records of patients with a BMI of ≥ 30 kg/m² were extracted from the Clinical Practice Research Datalink (CPRD), and analyzed.

The patients with IIH were older and more likely to have peripheral vascular disease, ischemic heart disease, and anemia; to have had a previous myocardial infarction; and have used non-steroidal anti-inflammatory drugs (NSAIDs) and steroids. Multivariate analysis with adjustment for confounders showed that anemia (p = 0.033) and the use of NSAIDs (p = 0.011) were the only factors independently associated with IIH. Increases in BMI beyond the threshold of obesity did not independently increase risk of IIH.

IIH is a multifactorial disease; the risk of which is increased in patients with a background of anemia, and those who use NSAIDs. Across BMI categories beyond the threshold for obesity (BMI ≥ 30 kg/m²), there is no continuation of the previously described "dose-response" relationship between BMI and IIH.

Scientific approval for the study was granted from the Regulatory Agency's Independent Scientific Advisory Committee and ethical approval by the Health Research Authority IRAS Project ID: 203143. ISAC approval registration number 16_140R2.