Taking antibiotics every day is the most effective way for women to prevent urinary-tract infections, followed by — in order of effectiveness — monthly acupuncture treatment, daily cranberry pills and daily estrogen therapy, according to a first-of-its-kind study by researchers at Los Angeles Biomedical Research Institute near Torrance.
The report, which will be published in the Wednesday issue of the journal Clinical Infectious Diseases, is a comprehensive analysis of previous studies on the various preventive treatments, which have been investigated in isolation but never in comparison to one another in this manner.
“The purpose of this is to synthesize the literature,” said Dr. Loren G. Miller, an investigator at LA BioMed and the study’s lead researcher. “There have been dozens and dozens of little studies, but nothing that has taken the studies together and looked at them in a more holistic and global way.”
The review comes amid growing concern about the threat of antibiotics resistance, fueling interest in other strategies for preventing the infections.
Miller said he was most surprised by the apparent success rate of cranberry pills, a widely known folk remedy often viewed with skepticism in the medical establishment. But he cautioned that high-quality research on this preventive measure is in short supply. Even more scant are reputable studies on acupuncture; researchers at LA BioMed found just two, both conducted in Sweden, Miller said.
“I was unaware acupuncture was even recommended or tried for urinary-tract prevention, let alone shown to reduce infections,” he said.
Every year, millions of women suffer from urinary-tract infections, resulting in some 6 million outpatient visits and 479,000 hospitalizations nationwide. Often brought on by dehydration, sexual activity or pregnancy, the infections produce symptoms that include a burning sensation when urinating, back and rib pain due to stressed kidneys and a sense of having to urinate often without the ability to do so.
About half of women suffer at least one urinary-tract infection in a lifetime. About a quarter who experience one will endure a second within six months, said Miller, who also serves as a professor of medicine at the David Geffen School of Medicine at UCLA.
Women are more susceptible than men because the urethra tube separating their bladders from the outside world is much shorter, providing less of an obstacle for the bladder-bound bugs.
The analysis at LA BioMed found that women who took antibiotics to prevent infections had the highest rate of success. The recurrence rate for this method was 0.4 a year. (An annual recurrence rate of 3.0 would mean the treatment has no measurable effect.)
The next most effective method, acupuncture, demonstrated a recurrence rate of 0.7 a year, though this number came with the caveat about the shortage of dependable studies. Estrogen therapy — which applies only to post-menopausal women — and cranberry pills both reduced the recurrence rate to 1.1 per year.
Miller said the problem with the cranberry method is that it is not standardized. The difference between supplements and juice isn’t widely studied, for instance, and the amount of concentrate varies widely by brand.
The researchers also looked at a fifth method, known as self-diagnosis and treatment, in which women take antibiotics without visiting the doctor only when they detect the symptoms of an infection.
Although this approach led to no discernible decrease in the recurrence rate, it was associated with the highest quality of life of all management strategies.
“If I was a woman with this, I would probably do the self-treatment,” Miller said. “I wouldn’t want to be bothered with going to the doctor. But everybody is different. Some say, ‘I just never want that infection again.’ ”
The LA BioMed review did not look at another emerging treatment that involves replenishing the body with naturally occurring bacteria to ward off infections. This can be done by eating yogurt, but Miller said a more direct approach is to apply the good bacteria — in the form of a lactobacillus suppository — directly to the vagina.
“There aren’t enough high-quality studies to model it at this time,” he said of the method, which he called promising.
In recent years, patients have been increasingly reluctant to take antibiotics for fear that overusing them could build resistance.
Indeed, scientists have found resistance in more infections — including some strains of urinary-tract infections caused by E. coli, a gut bacteria and a common culprit. One troubling study by the University of Manitoba put the resistance rate for trimethoprim/sulfamethoxazole, an antibiotic commonly prescribed to treat urinary-tract infections, at 21 percent, according to WebMD.
The LA BioMed study also sought to compare the costs of the various treatments. On average, patients paid $140 a year out of pocket for the antibiotics and nearly $950 a year for acupuncture. The discrepancy owes largely to how antibiotics are often covered by health insurers, whereas the cost for acupuncture is typically borne entirely by patients.
The meta-analysis reviewed six studies on the preventive effectiveness of antibiotics, four on cranberry pills, five on estrogen therapy and two on acupuncture.
Ultimately, Miller said he doesn’t recommend any particular method over another.
“Because patient preferences are very diverse, we laid out the benefits and costs of each approach to help the patient and provider choose an approach that best suits the patient’s lifestyle and preferences,” he said.