The 979 patients diagnosed and treated for iNPH during 2004–2011 and registered in the SHQR before September 2014 were included. The patients were registered at five of the six neurosurgical centers in Sweden: the University Hospitals in Umeå (n = 119), Uppsala (n = 313), Linköping (n = 164), Gothenburg (n = 148), and Lund (n = 235). During this period, the sixth neurosurgical center in Sweden did not report to the SHQR.