Interesting note at the wikipedia article on Phyllis Diller:
She died suddenly, on August 20, 2012, of unknown causes at the age of 95, in her home, surrounded by family and friends. The exact cause of her death came under investigation, and an autopsy and toxicology tests were scheduled. However, the results were not expected to be available for at least 4 weeks.
Quoting myself, to explain my interest in the entry at wikipedia which has since been removed:
In my experience, autopsies are not routinely conducted on aged persons when they pass away. That said, "Old Age" is not an official COD, afaik. Typically the COD is listed on the Death Certificate as one or a number of conditions from which the person suffered in her/his last months or years. I suppose sometimes it might be stated as respiratory/cardiac failure.
In this instance as well as in others I am aware of in my personal life, a friend or relative may have questioned the exact COD if it were, say, quasi-assisted.
I'll leave it at that.
hth
~jmo~