Urinary catheters are the most common source of hospital-acquired infections. A new analysis suggests that silver-coated catheters could cut that rate in half while still trimming costs.
University of Michigan
Embargoed for 3 p.m. CT Sept. 24, 2000
Silver-coated catheters cut infections & may save money, analysis finds
ANN ARBOR, Mich. - Almost anyone who has been in a hospital knows it: Having a urinary catheter is one of the least pleasant parts of your stay. But it can also be risky; catheters are the most common source of hospital-acquired infections, leading to hundreds of thousands of painful and costly urinary tract infections that must be treated with antibiotics.
Now, a new University of Michigan analysis suggests that there may be a way to cut catheter-related problems in half. Silver-coated catheters, the study indicates, could reduce patients' pain, suffering and hospital time, while cutting costs for hospitals and insurers. While they're more expensive than uncoated catheters, the silver-coated models prevent more urinary tract infections, or UTIs, the analysis suggests, which may also save money in the long run.
The study, in the Archives of Internal Medicine's Sept. 25 issue, is based on a sophisticated computer simulation incorporating past research on the UTI rates of different kinds of catheters and the cost of treating patients for such infections. The authors have no financial relationship with any catheter manufacturer.
Already, the results have prompted the U-M Health System to switch to silver-coated catheters for patients at highest risk of infection. The study's authors have now launched a prospective study to see if the predictions produced by the simulation come true in practice.
"We can't say that silver-coated catheters are a silver bullet," says Sanjay Saint, M.D., MPH, an assistant professor in the U-M Department of Internal Medicine. "But our study suggests that for about five dollars more apiece, the risk of a UTI is significantly reduced, and hundreds or even thousands of dollars can be saved for every symptomatic infection prevented. Additionally, preventing this common hospital-acquired infection will reduce the use of broad-spectrum antibiotics and thus may decrease the chance that bacteria will develop antibiotic resistance."
Catheters are a common feature of hospital care, used by about four million hospital patients a year some time during their stay. Inserted into the urethra, they collect urine from patients who can't use a bathroom or need to have their urine output monitored.
The chances of getting a UTI from a catheter are pretty high. Overall, such infections account for more than a third of all hospital-acquired infections - more than 600,000 in all each year.
A national survey by the Centers for Disease Control and Prevention found as many as 10 UTIs for every 1,000 days that catheters are used.
UTIs don't always produce symptoms. Usually, an individual with a UTI will feel an overwhelming urge to urinate frequently, accompanied by a burning sensation. Rarely, UTIs can cause bleeding during urination, high fever and accompanying abdominal and back pain. Worse yet is bacteremia, in which the bacteria enter the bloodstream and can cause fever, low blood pressure, confusion and life-threatening symptoms.
The risk of an infection, and the potential for a more serious one, increases with the number of days the catheter is in. Some patients, like women who have just given birth, use them only for several hours. But many more, including surgery and intensive care patients, use them for days at a time, increasing the chance that bacteria will travel up the catheter and into the bladder.
Saint and his colleagues looked at those who used catheters for 2 to 10 days, in hospital units for intensive care, post-surgical care, general medical care, and urology care. They tallied data from numerous studies of infection rates, catheter effectiveness and the kinds of treatments used for infections. Then, they used cost information from the U-M and other hospitals to estimate how much it would cost to detect, test for and treat infections, and how much longer an infection would keep a patient in the hospital.
Feeding all the data into a computer model and making conservative assumptions, they found that silver-coated catheters could decrease the incidence of symptomatic UTI by 47 percent, and the incidence of bacteremia 44 percent.
The cost savings could be substantial. The researchers calculated the cost of detecting and treating a symptomatic UTI at up to $400, and the cost of detecting and treating bacteremia at more than $2,000. Their model showed that silver-coated catheters could save money not only in individual cases, by preventing any one person's infection, but that they were also cost-effective across the board, saving an average of $4 per patient catheterized. In other words, the more expensive catheters might pay for themselves - and then some.
"These results are exciting from the perspective of both quality of care and cost. If our estimates of improved patient safety and lower hospital costs bear out in reality, the switch to coated catheters should be a no-brainer for health care providers," says co-author Mark Fendrick, M.D., an associate professor of internal medicine and co-director of the U-M's Consortium for Health Outcomes, Innovation and Cost Effectiveness Studies (CHOICES). "However, more and better information about the impact of these catheters in a variety of real-word settings will be needed to either validate or dispute our findings."
The silver-coated catheters analyzed in the study are covered with a thin layer of silver alloy, which is a known bacteria killer. Silver oxide, which was once used to coat some catheters, does not work nearly as well, according to an analysis Saint and colleagues published in 1998.
The study was funded by the Association of Practitioners of Infection
Control Research Foundation. Saint was a Robert Wood Johnson Clinical Scholar
at the time the study began.