BV follow-up at 3 months; Single-dose metronidazole: 65% clinical cure rate

OB/GYN News, Sept 15, 2004 by Doug Brunk

SAN DIEGO -- A single, 2-g dose of metronidazole given orally for the treatment of bacterial vaginosis resulted in a clinical cure rate of 65% and a therapeutic cure rate of 25% at 3 months, results from the largest study of its kind have shown.

"The data about long-term outcomes in women with bacterial vaginosis treated with single-dose metronidazole are very limited," Dr. Harold C. Wiesenfeld said at the annual meeting of the Infectious Diseases Society for Obstetrics and Gynecology. "There are no long-term studies, [and] all of the published treatment trials to date involved no more than 100 women."

Recommended treatment for bacterial vaginosis (BV) includes both oral and topical metronidazole and clindamycin. "Unfortunately, these regimens are far from ideal, with up to a 40% failure rate 1 month following treatment." Dr. Wiesenfeld said.

He and his associates conducted an observational cohort study of women who presented with pelvic infections at ambulatory sites in Pittsburgh during 1998-2000. Inclusion criteria included women aged 15-30 years who met at least three out of four Amsel criteria for BV. Exclusion criteria included pregnancy, recent antibiotic use, recent gynecologic surgery, having an IUD, or women whose first follow-up was more than 6 months from enrollment.

All women underwent pelvic exam, microbiologic tests of vaginal fluid, and cervical swabs for Chlamydia trachomatis and Neisseria gonorrhoeae. All took a single, 2-g dose of metronidazole, for BV, plus a 1-g dose of azithromycin and a 400-mg dose of cefixime, for empiric treatment of cervicitis. A follow-up evaluation was conducted a mean of 15 weeks after treatment in the National Institutes of Health-supported study.

Clinical cure was defined as improving from three or more Amsel criteria for BV to fewer than three criteria.

Therapeutic cure was defined as improving from four out of four Amsel criteria plus a Gram stain score of greater than 4 to no Amsel criteria and a Gram stain store of 0-3.

Of the 249 women who met enrollment criteria, 161 (65%) met the definition of clinical cure at 3 months, said Dr. Wiesenfeld of the department of ob.gyn. at Magee-Womens Hospital, part of the University of Pittsburgh.

However, only 52 (25%) of the remaining 207 women met the definition of therapeutic cure at 3 months, he noted.

Multivariate analysis revealed that statistically significant variables associated with clinical failure were African American race (odds ratio [OR] 3.9), smoking (OR 1.9), and colonization with Mycoplasma hominis (OR 3.3). The use of condoms and oral contraceptives had some protective effect against clinical failure, but they did not reach statistical significance.

Limitations of the study "include the fact that there was a long time interval between enrollment and follow-up," Dr. Wiesenfeld said. "Three months is a long time, and many events can occur during that time interval, such as recurrence of BV or acquisition of sexually transmitted diseases."

Also, he added, study participants received concomitant antibiotics at the time of enrollment. "Single doses of azithromycin and cefixime could certainly have an impact on vaginal flora, which will then translate into differences in [treatment] failures," he said.

BY DOUG BRUNK

San Diego Bureau