Methods. We conducted a randomized, controlled
trial to determine whether selective testing for cervical
chlamydial infection prevented pelvic inflammatory disease.
Women who were at high risk for disease were
identified by means of a questionnaire mailed to all
women enrollees in a health maintenance organization
who were 18 to 34 years of age. Eligible respondents
were randomly assigned to undergo testing for C. trachomatis
or to receive usual care; both groups were followed
for one year. Possible cases of pelvic inflammatory
disease were identified through a variety of data
bases and were confirmed by review of the women’s
medical records. We used an intention-to-screen analysis
to compare the incidence of pelvic inflammatory
disease in the two groups of women.