From the Journals

USPSTF: Screening pregnant women for asymptomatic bacteriuria cuts pyelonephritis risk



Pregnant women should be screened for asymptomatic bacteriuria using urine culture because the benefit of reducing pyelonephritis during pregnancy slightly but significantly outweighs the risks of maternal and fetal antibiotic exposure, according to new recommendations set forth by the United States Preventive Services Task Force (USPSTF).

A jar containing a urine sample toeytoey2530/Thinkstock

However, the investigating committee reported, there is evidence against screening nonpregnant women and adult men. In fact, the committee found “adequate” evidence of potential harm associated with treating asymptomatic bacteriuria in adults of both sexes, including adverse effects of antibiotics and on the microbiome.

The new document downgrades from A to B the group’s prior recommendation that urine culture screening for asymptomatic bacteriuria should be performed among pregnant women at 12-16 weeks’ gestation or at their first prenatal visit. The USPSTF recommendation to not screen nonpregnant adults retained its D rating, Jerome A. Leis, MD and Christine Soong, MD said in an accompanying editorial.

“Not screening or treating asymptomatic bacteriuria in this population has long been an ironclad recommendation endorsed by the Infectious Diseases Society of America, as well as numerous professional societies as part of the Choosing Wisely campaign,” wrote Dr. Leis of Sunnybrook Health Sciences Centre, Toronto, and Dr. Soong of the University of Toronto. “Restating this steadfast and pervasive recommendation may seem unremarkable and almost pedantic, yet it remains stubbornly disregarded by clinicians across multiple settings.”

The new recommendations were based on a review of 19 studies involving almost 8,500 pregnant and nonpregnant women, as well as a small number of adult men. Most were carried out in the 1960s or 1970s. The most recent ones were published in 2002 and 2015. The dearth of more recent data may have limited some conclusions and certainly highlighted the need for more research, said Jillian T. Henderson, PhD, chair of the committee assigned to investigate the evidence.

“Few studies of asymptomatic bacteriuria screening or treatment in pregnant populations have been conducted in the past 40 years,” wrote Dr. Henderson of Kaiser Permanente Northwest, Portland, and associates. “Historical evidence established asymptomatic bacteriuria screening and treatment as standard obstetric practice in the United States.” But these trials typically were less rigorous than modern studies, and the results are out of touch with modern clinical settings and treatment protocols, the team noted.

Additionally, Dr. Henderson and coauthors said, rates of pyelonephritis were about 10 times higher then than they are now. In the more recent studies, pyelonephritis rates in control groups were 2.2% and 2.5%; in most of the older studies, control group rates ranged from 33% to 36%.

In commissioning the investigation, the task force looked at the following four questions:

Does screening improve health outcomes?

Neither of two studies involving 5,289 women, one from Spain and one from Turkey, addressed this question in nonpregnant women; however, studies that looked at pregnant women generally found that screening did reduce the risk of pyelonephritis by about 70%. The investigators cautioned that these studies were out of date and perhaps methodologically flawed.


Next Article: