Five hundred and forty-three women were enrolled in the BV ancillary study between February and October 2004; 9 subjects did not have baseline and 6 subjects did not have follow-up BV results leaving 528 (97%) evaluable subjects (). Baseline sociodemographic characteristics, sexual behavior, and STIs were similar between the intervention and control arms (). At enrolment, 102 (39%) in the intervention arm and 111 (42%) in the control arm had BV. Since the prevalence of BV during followup differed predictably between women with and without BV at enrollment, we analyzed both groups separately.
Figure 1 Bacterial vaginosis (BV) ancillary study trial profile: *number with an evaluable vaginal Gram stain at each follow-up visit by arm and percent evaluable over total number enrolled in each arm (number evaluable is less than those presenting for followup (more ...)
Baseline demographics, clinical and exam findings, and initial laboratory findings for trial participants by group assignment.
Over the course of the study, participants randomized to the intervention arm reported consistent (always) diaphragm use during the previous three months at 904 (60.1%) out of 1505 visits. Women also reported always using gel at 908 (60.3%) visits indicating that in most instances when the diaphragm was used, gel was used as well. At enrollment, 29% of women reported always use a condom during the previous three months while 74% of women reported condom use at last sex with no significant differences found between study arms (). During followup a greater proportion of women enrolled in the control arm reported condom use at last sex (range per visit: 78%–88%) than in the intervention arm (range per visit: 45%–60%).
For participants with BV at baseline, the odds of prevalent BV decreased an average of 12% per visit with a 60% overall decline from baseline during followup (OR = 0.40, 95% CI 0.25–0.65); this decline was similar between arms (P = 0.99; ). For those without BV at enrollment, the odds of prevalent BV increased nonsignificantly during the study in comparison to baseline an average of 6% per visit with a 50% overall increase for participants in the intervention arm (OR = 1.5, 95% CI 0.99–2.25) in comparison to a 3% per visit and a 24% overall increase from baseline for women in the control arm (OR = 1.24, 95% CI 0.77–1.99); this increase was not significantly different between arms (P = 0.55; ).
Intent-to-treat (ITT) analysis of percent of subjects diagnosed with bacterial vaginosis (BV) during followup among participants randomized to the intervention and control arms stratified by presence or absence of BV at enrolment.
Only 2.1% of participants were treated for symptomatic BV, and antibiotic use during the last four weeks for any indication was reported infrequently during the course of the study (range per visit: 0.2%–0.7%). Use of water to clean the vagina in the past two weeks was common during followup and did not significantly differ by study arm; intervention arm range per visit: 67%–77%; control arm range per visit: 64%–76%. Use of other products to clean the vagina in the past two weeks was less commonly reported overall and did not differ by study arm during the course of the study either; intervention arm range per visit: 6%–12%; control arm range per visit: 5%–12%.
In the ITT analysis, BV prevalence over time did not differ between the intervention and control groups for women who had BV at enrollment (OR = 1.01, 95% CI 0.52–1.94, P = 1.0) and did not have BV at enrollment (OR = 1.21, 95% CI 0.65–2.27, P = 0.5) (, ). In the per-protocol analysis, limited to women reporting diaphragm use at last sex, women in the intervention arm with and without BV at enrollment did not have an altered odds of BV (OR = 0.90, 95% CI 0.46–1.76; and OR = 1.34, 95% CI 0.68–2.62, resp.) in comparison to the control arm (). We performed a second per-protocol analysis limited to women reporting consistent diaphragm use since the last visit in the intervention arm; women without BV at enrollment had a nonsignificant increased odds of BV (OR = 1.83, 95% CI 0.90–3.71) compared to those in the control arm; the intervention was not associated with an altered odds of BV in women with BV at enrollment (OR = 1.17, 95% CI 0.56–2.45) ().
The odds of prevalent bacterial vaginosis (BV) during followup in participants randomized to intervention compared to control arms, stratified by presence and absence of BV, normal vaginal flora, and normal lactobacillus at enrollment.
Two further a priori analyses were performed. First, we compared the prevalence of BV between groups at followup, restricted to women with normal vaginal flora (Nugent's score 0–3) at enrollment. Participants in the intervention group with normal vaginal flora at enrollment did not have an altered odds of BV during followup in comparison to the control group in ITT (OR = 1.37, 95% CI 0.62–3.07) and in per-protocol analysis limited to women who reported diaphragm use at last sex (OR = 1.64, 95% CI 0.71–3.82). However, women with normal vaginal flora at enrollment reporting consistent diaphragm use since their last visit had an increased odds of BV during followup (OR = 2.52, 95% CI 1.02–6.22) in comparison to the control arm (). Next, we compared the prevalence of BV among participants with normal Lactobacillus (score: 0-1) found on Gram stain at enrollment. Among women with normal Lactobacillus on Gram stain at enrollment, being in the intervention arm was not associated with an altered odds of BV during followup in ITT or in the two per-protocol analyses () in comparison to the control arm.