Stage 1 = mild
Stage 2 = moderate
Stage 3 = complex
Stage 4 = advance
Stage 5= end of life
Pd can also jump up in half steps ie stage 3.5 and stage 5 although called end of life pd is not terminal you die with pd not because of pd.
Great thread for newbies without more detailed information on what the stages involve. It's out there if you Google.