[0des]

It is because it is a symptom.

As an example: Nobody cares about clubbed fingernails either, but it can indicate something much worse.

[wincy]

I was really concerned you were talking about the old wives tale that clubbed fingers meant you were more likely to be a criminal or something… but I googled it and apparently it correlates to having lung cancer? Interesting.

[genocidicbunny]

Can be correlated to lung cancer, or heart disease.