The best information I have on crime statistics for that area is in the web reference below. Just enter in 91001 in the zip code and you'll reach the site. Trulia won't allow me to put the entire direct link. The site has a map for different areas of Pasadena and Altadena, including the area East of Fair Oaks you're talking about. So that's the statistical side. On the personal side, I live in that area of Pasadena North of the 210 Freeway and the safety really does change block by block. I'm on a pretty good block so it's not too dangerous for us, but it's still not as safe as an area where there's low crime for miles around.
Regarding Altadena vs. North West Pasadena, it depends on which block you're talking about. You'll probably have to evaluate that question on a house-by-house basis.
We have some friends that live on Sacramento near Lake Ave in Altadena, and police officers have told them it's a high crime area, but they haven't had any problems to my knowledge. My experience is if you don't leave valuables in your car, don't wander around at night, and stay aware of who's around you, you're probably okay.
Keller Williams Realty