Higher risk of kidney infection among women with a history of incontinence and diabetes

Researchers at Seattle-based Group Health Cooperative and the University of Washington (UW) report that some of the same factors that put women at risk for simple, lower urinary tract infections (UTIs) - as well as some unexpected factors - also make them susceptible to more serious kidney infections.

Lead researcher Delia Scholes, PhD, senior investigator at Group Health Cooperative’s Center for Health Studies and colleagues found that, like bladder infections, kidney infections in women under age 50 are linked to:

• Frequent (more than three times per week) sexual intercourse in the previous 30 days
• A recent urinary tract infection
• A new sex partner in the previous year
• Having a mother with a history of UTIs
• Recent spermicide use

In addition, the researchers found a higher risk of kidney infection among women with a history of incontinence and diabetes. The study appears in the January 4 issue of the Annals of Internal Medicine.

“The incontinence finding is still a bit of a puzzle,” said Scholes. “More research will be needed to understand the type of incontinence that is associated with kidney infections, as well as whether incontinence typically occurred before or after the kidney infection symptoms. The role of diabetes also warrants further study.”

The study fills a gap in knowledge about a condition that affects more than 250,000 women in the United States each year. Most of what is known about kidney infections comes from studies of older, hospitalized patients. What the Group Health/UW study shows is that the great majority of these infections—over 90 percent—occur in essentially healthy women who are treated on an outpatient basis.

The study’s findings support the conventional view that kidney infections likely follow bladder infections and thus may help doctors identify patients at risk for kidney infections, so that they may be encouraged to follow advice for preventing lower UTIs.

To conduct the study, the researchers interviewed 242 women, age 18 to 49, who had been treated for kidney infections at Group Health outpatient medical centers. They also collected information about their treatment from laboratory, pharmacy, enrollment, and other automated databases. Then they compared data from these cases to data from 546 similar women with no history of kidney infections in the previous five years.

The study was funded by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The co-authors are Thomas M. Hooton, MD, Pacita L. Roberts, MS, Ann E. Stapleton, MD, and Walter E. Stamm, MD, at the University of Washington, and Kalpana Gupta, MD, MPH, now at Yale University.