Yep I agree with hamster... deception (to me) is purposefully lying about something and I don't think in anyway shape or form you not disclosing your personal medical history to your friends is deceitful.

To be honest I only have a few friends that know my BP diagnosis but MOST of my friends do not. It's none of their business and although I know most would still accept me and not judge me if I told them... I still see no reason to tell them!