Joan Rivers said something to the effect of "of course Michelle Obama is actually a dude, it's obvious" on camera. A short time later, she died due to complications during a minor surgery. To quote Wikipedia on it:

After nearly two months of investigations, federal officials said on November 10 that the clinic made a number of mistakes both before and during the procedure. Among those were the clinic's failure to respond to Rivers' deteriorating vital signs, including a severe drop in her blood pressure, possibly administering an incorrect anesthetic dosage, performing a surgical procedure without her consent, and other medical-clinic irregularities.