Women suffer most from urinary tract infections, men more likely to be hospitalized

The first-of-its-kind research for the most common bacterial infection in the U.S. is important in providing predictors of hospital admission at a time when the health care industry is searching for ways to reduce costs.

"We found that those patients who were hospitalized for treatment of urinary tract infections were most often older men, as well as those with serious kidney infections," says Jesse D. Sammon, D.O., a researcher at Henry Ford's Vattikuti Urology Institute and lead author of the study.

"They were also more likely to be seen at urban teaching hospitals, and/or treated in zip codes with higher median incomes."

The study is published in the September issue of World Journal of Urology.

Citing previous studies, the Henry Ford researchers noted that costs rise tenfold when UTI patients require hospitalization. Being able to predict who among the annual patient load for UTI are most likely to be admitted to the hospital may help contain the rising costs of their care.

The study focused on 10.8 million patients with a primary diagnosis of UTI – specifically cystitis (bladder infection) and/or pyelonephritis (kidney infection) – who were seen in American hospital emergency departments from 2006 to 2009. This data was drawn from the Nationwide Emergency Department Sample, the largest all-payer emergency department database in the U.S.

Of those 10.8 million patients, 1.8 million – or 16.7 percent – were admitted to the hospital for further treatment.

Citing data for 1997 – 10 years before the current study period – the researchers noted that urinary tracts infections accounted for fewer than one million emergency department visits resulting in 100,000 hospitalizations.

"Over the current study period, 2006 to 2009, there was an average of 2.7 million emergency department visits each year for UTI, leading to 450,136 admissions," Dr. Sammon says. "This rapid rise has exceeded all previous estimates."

In 2007 alone, the research showed, there were more than 8.6 million outpatient visits for UTI, 23 percent of which were in emergency departments, with 84 percent of them made by women.

"This translated into a direct cost of $1.6 billion per year to the U.S. health care system," says Dr. Sammons. "UTIs are especially common in women. By age 32, half of women report having had at least one."

"For men and women, the incidence of going to the emergency department with a UTI was highest among the elderly, yet women saw a 'peak' in such cases between age 15 and 25, corresponding to the onset of sexual activity."

But it was men who were most likely to be admitted for inpatient care, especially elderly men and those with acute kidney infections that required treatment with intravenous antibiotics.

While attributing a rise in the U.S. hospitalization rate for UTI in part to the country's aging population, the researchers said increasing levels of diabetes and other illnesses among the patients, and rising resistance to antibiotics, also were factors.

"Managing these high-risk patients more aggressively in the outpatient setting may prevent unnecessary hospitalizations and reduce associated health care costs," Dr. Sammons says.