A screening test for chlamydia may not reduce the incidence
of pelvic inflammatory disease in women, according to results of a recently
Pippa Oakeshott, MD, of St. Georges,
University of London, and colleagues recruited 2,529 women between the ages of
16 and 27 for the Prevention of Pelvic Infection trial. Participants completed
a questionnaire and provided researchers with self-administered vaginal swabs.
The swabs were either screened immediately (1,254 women) or stored for one year
and then analyzed (1,265 women for controls).
The prevalence of chlamydial infection at baseline was
5.4% among women who were screened immediately and 5.9% among controls. Pelvic
inflammatory disease occurred in 1.3% of 1,191 screened women and 1.9% of 1,186
women in the control group (RR, 0.65; 95% CI, 0.34 to 1.22).
Pelvic inflammatory disease occurred most frequently in
women who tested negative for chlamydia at baseline, at a rate of 79%. Among 63
women in the screened group who had baseline samples that were positive for
chlamydia, 1.6% developed the disease during follow-up (RR, 0.17, 0.03-1.01).
Among 74 women in the control group with baseline samples that were positive
for chlamydia, 9.5% (95% CI, 4.7% to 18.3%) developed pelvic inflammatory
disease during the follow-up period.
The researchers noted that 22% of participants received
independent testing for Chlamydia during the follow-up period, which may have
reduced the effect of screening and influenced the study results.
Although some evidence shows that screening
reduced rates of pelvic inflammatory disease, especially in women with
chlamydial infection at baseline, the absolute number of cases prevented was
small, the researchers wrote.
The researchers wrote that women should be encouraged to
get repeat testing each time they have a new sexual partner.
Oakeshott P et al. BMJ. 2010;340:c1642.