Long-term outcomes after shunt surgery in older patients with idiopathic normal pressure hydrocephalus

This study aimed to evaluate the survival and functional outcomes in older patients with idiopathic normal pressure hydrocephalus (iNPH) following shunt surgery.

We performed shunt surgery in patients with iNPH and followed up at an outpatient clinic. The survival time was analyzed using Kaplan-Meier survival analysis. The maintenance period of activities of daily living (ADL) was measured using the modified Rankin Scale in part of patients.

Out of 200 patients with iNPH (mean age, 78.1 years old, standard deviation, 5.0), 110 had a lumboperitoneal shunt, 68 had a ventriculoperitoneal shunt, and 22 had a ventriculoatrial shunt. The median follow-up time was 5.0 years for all patients, with 99 (49.5 %) dying during the follow-up period. The median overall survival was 7.7 years (5.9 years in males, 8.8 years in females, P = 0.006). The common causes of death were senility, pneumonia, and cancer. Decreased ADL was observed in 66 out of 88 patients (75.0 %) during a median follow-up of 2.2 years. The maintenance period of ADL was 2.6 years in both sexes. The most common cause of decreased ADL was a progression of frailty, followed by pneumonia and stroke. Patients over 80 had similar survival times and ADL maintenance periods as those under 80.

The survival time of patients with iNPH after shunt surgery was 7.7 years, and females lived longer than males. Older patients over 80 years old had relatively good survival outcomes. Frailty progressed continuously in patients with iNPH after surgical treatment.