The Spanish flu of 1918 was most likely a similar strain, but I would suggest that the high mortality rate was due to poor infection controls and subsequent secondary infections. Though I have heard it said on documentaries (like Influenza 1918) that the flu that year caused filling of the lungs with fluid, the symptomology is reminiscent of an infection with Klebsiella pneumoniae.
Even if that is the case, this year's H1N1 strain is especially dangerous to the young, the old, anyone with a compromised immune system, or anyone with respiratory complications, such as asthma.