Urolithiasis, stone-related infection rising, ER data show

February 2, 2013

For reasons that are unclear, the number of patients treated for urinary stones in American hospitals after being referred from emergency rooms grew by almost 25% from 2002-2009, a new study finds.

Istanbul, Turkey-For reasons that are unclear, the number of patients treated for urinary stones in American hospitals after being referred from emergency rooms grew by almost 25% from 2002-2009, a new study finds. The percentage of patients with infections rose too, from 22% to 33%.

There’s another intriguing finding from the study’s analysis of a national database of information about inpatients: The percentage of patients who received treatment via interventions instead of observation and medication remained steady at about 40%.

“I’m surprised by the number of interventions that are currently being undertaken in the acute setting. If I’d guessed, I would have thought they would be much less common,” senior author Kent T. Perry, Jr., MD, professor of urology and co-director of the endourology and minimally invasive surgery fellowship at the Northwestern University Feinberg School of Medicine, Chicago, told Urology Times.

After all, he said, it’s becoming more common for urologists in private practice to avoid performing procedures on patients with urinary stones and instead send them home with medication to encourage passing of the stones.

For the study, which was presented at the 2012 World Congress of Endourology and SWL in Istanbul, Turkey, Dr. Perry and his colleagues used Nationwide Inpatient Sample data from 2002-2009 to identify all patients admitted from the emergency department with a diagnosis of urolithiasis. Patients were substratified to those with and without infection. The authors analyzed rates of stent placement, ureteroscopy, shock wave lithotripsy, and nephrostomy placement.

In 2002, a total of 285,174 patients were treated for urinary stones. Of those, 18% underwent ureteroscopy, 15% had a stent procedure, 5% underwent nephrostomy, 4% underwent SWL, and 56% had no procedure.

Only a few numbers changed much by 2009. The total number of patients rose to 354,047, the percentage of those who underwent ureteroscopy fell to 15%, those who had a stent rose slightly to 16%, 6% underwent nephrostomy, and the percentage who underwent SWL fell to 2%. The percentage who didn’t have procedures rose to 60%.

In both years, there was little difference in the percentages of patients with or without infections who did not undergo a procedure: they ranged between 56% and 60%.

Dr. Perry said hospitals might be lagging urology as a whole in terms of treating urinary stones with observation and medication because patients with more acute symptoms are likely to show up in the ER.

Reason for patient increase unclear

Why might the number of patients have risen so much over just 7 years?

First author Samuel H. Eaton, MD, speculated that hospitals might be admitting more patients because of concern about malpractice allegations if they don’t. Or, he said, a “more nefarious” prospect is that hospitals, especially for-profit institutions, are trying to boost their inpatient numbers for financial reasons.

Dr. Perry said the researchers plan to write up their findings for publication and try to gain more insight from the available statistics. But that will be a challenge, according to Dr. Eaton.

“The downside of using a large database is that while it allows you to get a good grasp of what’s going on, it’s hard to drill down and figure out what’s leading to that,” said Dr. Eaton, an endourology fellow at Northwestern. “Parsing out exactly why someone gets admitted, even when you’re able to look at ­individual charts, is always a little bit challenging.”