Imperial College London


Faculty of MedicineSchool of Public Health

Clinical Senior Lecturer in Epidemiology



+44 (0)20 7594 8994bethan.davies06




Medical SchoolSt Mary's Campus






BibTex format

author = {Davies, B and Ward, H and Leung, S and Turner, KME and Garnett, GP and Blanchard, JF and Yu, BN},
doi = {infdis/jiu483},
journal = {Journal of Infectious Diseases},
pages = {S549--S555},
title = {Heterogeneity in Risk of Pelvic Inflammatory Diseases After Chlamydia Infection: A Population-Based Study in Manitoba, Canada},
url = {},
volume = {210},
year = {2014}

RIS format (EndNote, RefMan)

AB - Background. The association between chlamydia infection and pelvic inflammatory disease (PID) is a key parameterfor models evaluating the impact of chlamydia control programs. We quantified this association using aretrospective population-based cohort.Methods. We used administrative health data sets to construct a retrospective population-based cohort ofwomen and girls aged 12–24 years who were resident in Manitoba, Canada, between 1992 and 1996. We performedsurvival analysis on a subcohort of individuals who were tested for chlamydia to estimate the risk of PID diagnosed ina primary care, outpatient, or inpatient setting after ≥1 positive chlamydia test.Results. A total of 73 883 individuals contributed 625 621 person years of follow-up. Those with a diagnosis ofchlamydia had an increased risk of PID over their reproductive lifetime compared with those who tested negative(adjusted hazard ratio [AHR], 1.55; 95% confidence interval [CI], 1.43–1.70). This risk increased with each subsequentinfection: the AHR was 1.17 for first reinfection (95% CI, 1.06–1.30) and 1.35 for the second (95% CI,1.04–1.75). The increased risk of PID from reinfection was highest in younger individuals (AHR, 4.55 (95% CI,3.59–5.78) in individuals aged 12–15 years at the time of their second reinfection, compared with individualsolder than 30 years).Conclusions. There is heterogeneity in the risk of PID after a chlamydia infection. Describing the progression toPID in mathematical models as an average rate may be an oversimplification; more accurate estimates of the costeffectivenessof screening may be obtained by using an individual-based measure of risk. Health inequalities may bereduced by targeting health promotion interventions at sexually active girls younger than 16 years and those with ahistory of chlamydia.
AU - Davies,B
AU - Ward,H
AU - Leung,S
AU - Turner,KME
AU - Garnett,GP
AU - Blanchard,JF
AU - Yu,BN
DO - infdis/jiu483
EP - 555
PY - 2014///
SN - 1537-6613
SP - 549
TI - Heterogeneity in Risk of Pelvic Inflammatory Diseases After Chlamydia Infection: A Population-Based Study in Manitoba, Canada
T2 - Journal of Infectious Diseases
UR -
UR -
VL - 210
ER -