Survival in treated idiopathic normal pressure hydrocephalus

Nina Sundström,Kerstin Andrén,Hanna Israelsson,Carsten Wikkelsø,Simon Agerskov,Mats Tullberg,Per Hellström,Katarina Laurell

doi:10.1007/s00415-019-09598-1

Nina Sundström, Kerstin Andrén + Show 6 more

Open Access

https://doi.org/10.1007/s00415-019-09598-1

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Abstract

ObjectiveTo describe survival and causes of death in 979 treated iNPH patients from the Swedish Hydrocephalus Quality Registry (SHQR), and to examine the influence of comorbidities, symptom severity and postoperative outcome.MethodsAll 979 patients operated for iNPH 2004–2011 and registered in the SHQR were included. A matched control group of 4890 persons from the general population was selected by Statistics Sweden. Data from the Swedish Cause of Death Registry was obtained for patients and controls.ResultsAt a median 5.9 (IQR 4.2–8.1) year follow-up, 37% of the iNPH patients and 23% of the controls had died. Mortality was increased in iNPH patients by a hazard ratio of 1.81, 95% CI 1.61–2.04, p < 0.001. More pronounced symptoms in the preoperative ordinal gait scale and the Mini-mental State Examination were the most important independent predictors of mortality along with the prevalence of heart disease. Patients who improved in both the gait scale and in the modified Rankin Scale postoperatively (n = 144) had a similar survival as the general population (p = 0.391). Deaths due to cerebrovascular disease or dementia were more common in iNPH patients, while more controls died because of neoplasms or disorders of the circulatory system.ConclusionsMortality in operated iNPH patients is 1.8 times increased compared to the general population, a lower figure than previously reported. The survival of iNPH patients who improve in gait and functional independence is similar to that of the general population, indicating that shunt surgery for iNPH, besides improving symptoms and signs, can normalize survival.

Highlights

Idiopathic Normal Pressure Hydrocephalus is a treatable and under-diagnosed disorder that affects 2–4% of persons aged 65 years or older [1,2,3,4]
Cardiovascular and cerebrovascular diseases have been reported as common causes of death in Idiopathic Normal Pressure Hydrocephalus (iNPH) patients [8,9,10], but this has not been thoroughly explored or compared to the general population
Data on a cohort of 979 iNPH patients operated 2004–2011 in 5 of the 6 neurosurgical centers in Sweden was extracted from the Swedish Hydrocephalus Quality Registry (SHQR) on the 1st of September 2014, see Table 1 for baseline characteristics

Summary

Introduction

Idiopathic Normal Pressure Hydrocephalus (iNPH) is a treatable and under-diagnosed disorder that affects 2–4% of persons aged 65 years or older [1,2,3,4]. Survival in untreated iNPH patients is substantially reduced, with a hazard ratio (HR) for death of 3.8 compared to the general population [7]. In treated iNPH patients, a relative risk (RR) for death of 3.3 [8] and a standardized mortality ratio (SMR) of 2.5 [9] have been calculated in single center studies—similar to the mortality of first-time stroke sufferers [8]. Cardiovascular and cerebrovascular diseases have been reported as common causes of death in iNPH patients [8,9,10], but this has not been thoroughly explored or compared to the general population. Risk factors for cerebrovascular disease, as well as comorbidity of cardio- and cerebrovascular diseases are common in iNPH [11,12,13], but it is unknown to what extent these factors influence survival in these patients.

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