He obviously felt that she looks like shit, probably bald, blotchy, and enormous, and was afraid that the staff that hasn't seen her in the past few months would be horrified. The image of her being wheeled into a good time party would be a huge bummer to everyone. Probably Artie would sooner get an invite, but the drugged up Quivers in a haze decides that she wants to go to the year end party too. I guarantee she will not show up and will have some bullshit excuse or something. My 2 cents.