CHICAGO -- Long-lasting erections that require emergent care may plague men more often than previously thought, researchers said here.

As many as 8.05 per 100,000 emergency department visits may be related to priapism, in which the penis doesn't return to its flaccid state, Andrew Flum, MD, of Northwestern University in Chicago, and colleagues reported during a poster session at the World Meeting on Sexual Medicine.

"Unfortunately we don't have a reliable way to tell if each encounter is a separate person or if one person presents multiple times," Flum said, adding, however, that even attempts to control for that fact turned up higher estimates than previously seen.

Action Points Note that this study was published as an abstract and was presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Explain that a database study estimated that emergency department visits for priapism in the U.S. were considerably more common than previously thought at about 8 per 100,000 visits compared with previous reports of 0.3 to 1.5 per 100,000.

Note that while concomitant sickle cell disease led to nearly four times the number of hospital admissions for priapism, only about 21% of cases were seen in association with a sickle cell diagnosis.

The researchers also noted a lower concurrence rate between presenting to the ED for the condition and sickle cell disease. Priapism is a serious complication of sickle cell disease.

A few small studies have suggested that the prevalence of priapism falls somewhere between 0.34 and 1.5 cases per 100,000 men.

Flum and colleagues looked at discharge data on ED visits from the Nationwide Emergency Department Sample (NEDS) and the Healthcare Cost and Utilization Project (HCUP), and weighted the results to calculate nationwide estimates. The mean patient age was 36.4.

Between 2006 and 2009, Flum and colleagues noted 8,738 visits to the ED for priapism in the U.S., which in weighted figures became an estimated 39,964 visits during that time.

That translated to a rate of 8.05 per 100,000 ED visits, higher than previous population estimates, the researchers said.

Flum said that when he and colleagues used zip codes to attempt to control for multiple visits by singular patients, they found that the figure fell to about six per 100,000 visits -- although that number was still higher than previous estimates.

The proportion of ED visits for priapism was higher in the southern U.S. at 9.78 per 100,000 visits. While this was partly due to the increased prevalence of sickle cell disease in that area, it does not fully account for differences, they said.

In fact, they added, a smaller portion of patients (21.1%) actually had sickle cell disease, which is lower than previous estimates among priapism cases.

Still, patients with sickle cell were significantly more likely to be admitted to the hospital during an ED visit for priapism than those without the condition. While the majority of patients overall were discharged home after their ED visit (72.1%), only about half of those with sickle cell disease were treated and sent home (49.6%).

That made sickle cell patients with priapism almost four times as likely to have to stay in the hospital as priapism patients without the blood condition (OR 3.84, 95% CI 3.67 to 4.05) when controlling for age, region, hospital type, and payer type.

Those hospital stays proved costly, the researchers added. While the overall mean hospital charge was $1,778 per encounter if patients were discharged home, costs jumped to $41,909 per encounter if a hospital stay was involved.

Flum and colleagues estimated that priapism costs about $110 million in the U.S. per year.

He added that in general, the prevalence of priapism has been on the rise over time, and that may have something to do with the increasing use of intracavernous injections for erectile dysfunction.

Ira Sharlip, MD, of the University of California San Francisco, who moderated the session during which the poster was presented, said he has seen a "dramatic increase" in the number of patients presenting with priapism due to the use of injection therapy.

While this version of these medications has been around for several years, he said, their popularity may be rising.

Better patient education about the proper use of these injectable drugs may help lower the prevalence of priapism, Flum said.

The researchers reported no conflicts of interest.