Chlamydia Testing Falls in Young Women, Following Change in Cervical Cancer Guidelines; Simultaneous Overtesting of Males Seen

Recent cervical cancer screening guideline changes are associated with reduced chlamydia testing, particularly among women aged 15 to 19 years, who are at high risk for chlamydia infection, if sexually active, according to a study published in the July/August issue of the Annals of Family Medicine. The authors say these findings highlight the need to separate screening for sexually transmitted infections (STI) from cervical cancer screening recommendations. Specifically, they call for risk-based chlamydia testing, regardless of the need for Papanicolaou (Pap) testing.

Chlamydia is the most commonly diagnosed bacterial STI worldwide, with the greatest disease burden seen among sexually active adolescents and young adults (aged 15 to 29 years), according to the U.S. Centers for Disease Control and Prevention. It had been common to screen women for chlamydia simultaneously with cervical cancer screening (Pap testing), but in 2012 the U.S. Preventive Services Task Force (USPSTF) and the American Cancer Society changed cervical cancer screening recommendations to eliminate screening for women younger than 21 years. Similar guidelines were subsequently adopted in Canada.

To assess the impact of the new recommendations on chlamydia screening, the Canadian researchers used population-based physician billing claims data to identify Pap and chlamydia tests and public health surveillance data to identify chlamydia cases covering the two years before and after the guideline change (May 2010 to July 2014). Males were included in the study as a comparison group, since the guideline changes were expected to have no impact on them.

The researchers found that Pap testing declined in all age groups following the guideline change, with the greatest relative reduction (25.5 percent) in young females aged 15 to 19 years. During the same time period there were also decreases in reported chlamydia incidence for females aged 15 to 19 years and 20 to 24 years (relative reductions of 16.8 percent and 14.4 percent, respectively).

“Assuming that the true incidence of chlamydia (symptomatic and asymptomatic combined) in the population was unchanged over this period, we estimated that 2,726 fewer cases of chlamydia were detected per year in Ontario following the guideline change,” write the authors led by Michelle S. Naimer, M.D., from University of Toronto in Canada. “The public health implications of reduced chlamydia screening over time include missed opportunities for clinical and public health management of cases and potentially increased spread of chlamydia infection by asymptomatic individuals.”

For males, chlamydia testing increased between 2010 and 2014, which the authors say was likely due to increased availability of non-invasive nucleic acid amplification testing of urine specimens. Despite the increase in testing, incidence of chlamydia remained steady for males. The authors say this finding affirms previous evidence suggesting insufficient justification for screening men with average risk.

Takeaway: Evidence shows the potential for negative public health effects resulting from decreased chlamydia screening following changes in cervical cancer guidelines. As such, it may be important to separate screening for STIs from cervical cancer screening recommendations.