Chlamydia testing and diagnosis following initiation of long-acting reversible contraception: A retrospective cohort study.Aust N Z J Obstet Gynaecol 2017; 57(6):665-675AN
Long-acting reversible contraception (LARC) effectively protects against pregnancy but provides no protection against sexually transmitted infections (STIs).
To compare rates of chlamydia testing and diagnosis for women initiating long-acting versus oral contraception.
MATERIALS AND METHODS
Retrospective cohort study involving data collection for 6160 women initiating post-abortion contraception at a large New Zealand regional public hospital abortion clinic (2009-2012), with chlamydia testing data obtained from the local laboratory during two-year follow up. Negative binomial regression modelling examined the effect of contraceptive method on two outcome measures: chlamydia testing and chlamydia diagnosis (adjusting for potential covariates of age, ethnicity, past chlamydia infection, pregnancy history) in year one and two of follow up.
Two thousand seven hundred and twenty nine women (44%) received a LARC and 1764 (28.6%) were prescribed oral contraception. Adjusted testing rates differed by contraceptive method only in year one (P < 0.01): with higher rates among copper intrauterine device users (relative risk (RR) 1.2, 95% CI 1.06-1.35), and lower rates for implant users (RR 0.84, 95% CI 0.72-0.99) compared with oral contraceptive users (reference group). No significant differences were observed in chlamydia diagnosis rates by contraceptive method (P > 0.05). Younger age, past chlamydia infection, Maori and Pacific ethnicity were associated with higher rates of chlamydia diagnosis (P < 0.01).
Known STI-related risk factors (age, ethnicity, past infection) but not contraceptive method were independently related to rates of subsequent chlamydia diagnosis. This suggests that increased LARC uptake would not occur at the expense of chlamydia control. Regular screening and risk reduction advice (including condom use) are important chlamydia control measures for at-risk groups.