Early treatment with CSF diversion reduces mortality in normal pressure hydrocephalus

Objective: We examined the effect of early vs delayed treatment with shunt surgery on mortality in idiopathic normal pressure hydrocephalus (iNPH). Background: iNPH is a treatable yet underdiagnosed disorder, and CSF diversion with shunt surgery is the main form of treatment. According to several uncontrolled trials, most patients improve after shunt surgery. However, randomized trials have been scarce and the effect of shunt surgery has been questioned. Furthermore, the effect of shunt surgery on mortality has previously not been studied. This observational study is based on a natural experiment in which a random group of iNPH patients were inadvertently exposed to a severe delay of treatment. Design/Methods: In 2010–2011 a group of iNPH patients (n=33) were unintentionally exposed to a delay of treatment due to several administrative and economic shortcomings at our university hospital (Waiting time for shunt surgery 6–24 months). These were followed up and compared to patients treated in normal fashion, within three months (n=69) at the same clinic. Median follow-up time was 6.2 years. The primary outcome was mortality. Kaplan-Meier survival curves and Cox proportional hazard models adjusted for several potential confounders were analyzed. Results: Crude five-year mortality was 14.5 % in those with early treatment compared to 44.1 % in those with delayed treatment (p=0.001). The age-adjusted hazard ratio (HR) for death, in those with delayed treatment, was 2.57 (95 % CI; 1.13–5.83), p=0.024. These findings remained significant after adjusting for symptom severity at baseline, surgical complications, duration of follow-up, hypertension and cardiovascular disease. Conclusions: The present data indicate that shunt surgery is effective, and that early treatment may increase survival. Disclosure: Dr. Andren has nothing to disclose. Dr. Wikkelso has received personal compensation for activities with Codman as a speaker. Dr. Wikkelso has receivedpersonal compensation in an editorial capacity for Acta Neurologica Scandinavica. Dr. Hellstrom has nothing to disclose. Dr. Tullberg has nothing to disclose. Dr. Jaraj has nothing to disclose.