When Helfand looked to see what bearing other health conditions might have had on treatment, he found those with prostate cancer were least likely to be treated. Only 15 percent were.
The study didn't have information on why the men went untreated, he said. But he speculates there are probably several reasons.
The undertreatment, Helfand said, is probably a result of doctors often not offering the prescription or patients getting a prescription but not filling it at the pharmacy.
"Men may not be bothered by it," he said. Or a doctor may not write a prescription because he may not think the man is a candidate, or perhaps they didn't respond to erectile dysfunction treatment in the past.
Other reasons, he said, could include costs and embarrassment.
For men, Helfand said, the message is: "There are available therapies out there. These can be useful if you have ED."
An expert who reviewed the study but was not involved said he isn't sure if it mirrors real life.
"To conclude from this study that three-fourths of the men who carry a diagnosis of ED are not treated doesn't fit with what we see in clinical practice," said Dr. Jacob Rajfer, a professor of urology with the David Geffen School of Medicine, at the University of California, Los Angeles.
"In order to determine how many men were treated or not treated, you need to interview the people," Rajfer said.
Men might get to the pharmacy, see the cost of the erectile dysfunction drug, and decide to go out of the country to get it and save money, or might get it by mail order, Rajfer said.
Another expert discussed possible barriers to men getting these drugs.
"Cost might be a big issue," said Dr. Ajay Nangia, an associate professor of urology at the University of Kansas Medical Center. He is familiar with the study findings.
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