Yes, yes, yes!
I bought disability insurance some years BEFORE I even suspected Lupus, I didn't find it costly at all (of course, that was way back in 1990). Once I was diagnosed and had to quit working the extra money has come in VERY handy!!!
Of course, if you are already in process and answer questions / physical honestly it may be hard to get, plus I understand policies are nothing like the "Cadillac policies" that used to be offered.
Lynnwood, Lupus & Sjogren's Moderator, Dx: 2002DIAGNOSING LUPUS & HW's LUPUS 101
"Life is far too important to be taken seriously." - Oscar Wilde