Imperial College London

DrBethanDavies

Faculty of MedicineSchool of Public Health

Clinical Senior Lecturer in Epidemiology
 
 
 
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Contact

 

+44 (0)20 7594 8994bethan.davies06

 
 
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Location

 

Medical SchoolSt Mary's Campus

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Summary

 

Publications

Citation

BibTex format

@article{Davies:2018:10.1371/journal.pmed.1002483,
author = {Davies, B and Turner, KME and Frolund, M and Benfield, T and Andersen, B and Westh, H and Ward, H},
doi = {10.1371/journal.pmed.1002483},
journal = {PLoS Medicine},
title = {Pelvic inflammatory disease risk following negative results from chlamydia nucleic acid amplification tests (NAATs) versus non-NAATs in Denmark: A retrospective cohort study},
url = {http://dx.doi.org/10.1371/journal.pmed.1002483},
volume = {15},
year = {2018}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - BackgroundNucleic Acid Amplification Tests (NAATs) are the recommended test type for diagnosing Chlamydia trachomatis (chlamydia). However, less sensitive diagnostic methods—including direct immunofluorescence (IF) and enzyme-linked immunoassay (ELISA)—remain in use in lower resourced settings. We estimate the risk of pelvic inflammatory disease (PID) following undiagnosed infection in women tested with non-NAATs and estimate the health gain from using accurate diagnostic tests.Methods and findingsWe used Denmark’s national Chlamydia Study dataset to extract all chlamydia tests performed in women aged 15–34 years (1998–2001). Tests were categorised as non-NAAT (IF/ELISA) or NAAT and limited to each woman’s first test in the study period. We linked test data to hospital presentations for PID within 12 months from the Danish National Patient Register. The study included 272,105 women with a chlamydia test, just under half (44.78%, n = 121,857) were tested using NAATs. Overall, 6.38% (n = 17,353) tested positive for chlamydia and 0.64% (n = 1,732) were diagnosed with PID within 12 months. The risk of PID following a positive chlamydia test did not differ by test type (NAAT 0.81% [95% CI 0.61–1.00], non-NAAT 0.78% [0.59–0.96]). The risk of PID following a negative test was significantly lower in women tested with NAATs compared to non-NAATs (0.55% [0.51–0.59] compared to 0.69% [0.64–0.73]; adjusted odds ratio (AOR) 0.83 [0.75–0.93]). We estimate that 18% of chlamydia infections in women tested with a non-NAAT were undiagnosed and that the risk of progression from undiagnosed chlamydia infection to PID within 12 months was 9.52% (9.30–9.68). Using non-NAATs could lead to an excess 120 cases of PID per 100,000 women tested compared to using NAATs. The key limitations of this study are under ascertainment of PID cases, misclassification bias in chlamydia and PID exposure status, bias to the association
AU - Davies,B
AU - Turner,KME
AU - Frolund,M
AU - Benfield,T
AU - Andersen,B
AU - Westh,H
AU - Ward,H
DO - 10.1371/journal.pmed.1002483
PY - 2018///
SN - 1549-1277
TI - Pelvic inflammatory disease risk following negative results from chlamydia nucleic acid amplification tests (NAATs) versus non-NAATs in Denmark: A retrospective cohort study
T2 - PLoS Medicine
UR - http://dx.doi.org/10.1371/journal.pmed.1002483
UR - http://hdl.handle.net/10044/1/55316
VL - 15
ER -