Can Anemia Lead To Coma?

Can anemia cause people to go in a coma? My nan this morning said she had a very bad night's sleep so we let her have some rest. When we tried to wake her up, she was unresponsive and has been since. She's in her late 70's, quite small but quite big in weight. She has severe anemia, arthiritis and depression because her doctors kept giving her the wrong tablets.