Risk Factors for Skull Base Spontaneous Cerebrospinal Fluid Leak in Patients with Idiopathic Intracranial Hypertension: A Multi-National Database Study

Objectives Skull base spontaneous cerebrospinal fluid leaks (sCSF leaks) represent a distinct cohort of patients with idiopathic intracranial hypertension (IIH). Patients with sCSF leaks often have comorbidities that are modifiable risk factors. In this study, we compare demographics and treatment modalities between IIH patients with sCSF leaks (IIHwL) and IIH patients without skull base sCSF leaks (IIHwoL), and characterize the risk of CSF leak development in IIH patients. Design Retrospective cohort study. Setting Electronic medical record data from the TriNetX Research database. Participants Patients > 18 years old with a diagnosis of IIHwL and patients with a diagnosis of IIHwoL. Main Outcome Measures Baseline demographic data and comorbidities were compared and sCSF leak risk evaluated. Shunt placement and medication use were compared for 3 years following diagnosis. Results 1,277 IIHwL patients and 90,074 IIHwoL patients were analyzed. IIHwL patients had higher rates of comorbid conditions (p<0.0001), smoking (p<0.0001), and were more likely to be prescribed acetazolamide (p<0.0001) or have a ventriculoperitoneal shunt placed (p=0.0001) compared to IIHwoL patients. Patients with IIH experienced an average cumulative increase in sCSF leak risk from 0.266% at 1 year to 0.6512% at 5 years. Conclusions These findings strengthen the association between IIH as a contributor to sCSF leak risk, and imply that longer-standing IIH further increases this risk. This is the first study to identify smoking as a potential sCSF leak risk factor, and to both describe and quantify the rate of risk increase for sCSF leak in IIH patients.