The late, great John Michael of CKTB used to respond to "How Are You?" with a simple "Thank You" and then let the caller talk. Short and without seeming rude. Maybe others should adopt that idea.   

Every talk show host has his or her own way of dealing with it. 

Rush Limbaugh famously allows his first caller to ask "how are you?" and everyone who follows simply says "ditto."  

Mark Levin, another syndicated right wing talk show host in the U.S., has a different take. He introduces many callers something like this. "Let's go to Stan listening on the great WABC. GO!" There's something about that emphasized "GO!" that makes people get to the point. Doesn't always work but from the few times I've monitored his show, it's surprisingly effective. 

And then there's the former host of Jays Talk on the Fan, Mike Wilner, who, after yet another caller asked him "How are you," used to make a joke of it by saying, "I continue to be fine."

None of them are especially good at ending the problem, but at least they cut down a little bit on the 'how are you' clutter.

Long ago, I stopped trying to prevent usually nervous callers from asking “how are you”. My response is pretty well always either “good” or “great”, just a single positive word with no further encouragement like “and you?” Callers get it.

I’d love it if the “as I was telling your screener” phrase would just disappear though. Haven’t figured that one out yet. What callers don’t get is that they’d not have gotten into queue if they hadn’t convinced the screener they should be and, that aside, hosts already have an on-screen message encapsulating what they plan to say.

milton wrote:

Tom Bauerle has a cute stock answer as well.

By all credible accounts Mr. Bauerle is mentally ill. For his safety and the safety of the listening public he should be moved to choose a new career.

As for his sidekick David...