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Cervical cancer guideline changes lead to less chlamydia testing

Recent changes to the cervical cancer screening guideline changes were associated with lower chlamydia testing rates and more reported new cases of chlamydia in females in Ontario, Canada, according to research recently published in Annals of Family Medicine.

Researchers also found that females aged 15 to 19 years, who are at high risk for chlamydia if sexually active, but are not indicated to receive routine cervical cancer screening under the new guidelines, were disproportionately affected.

The findings pose a potentially significant concern. According to the CDC, chlamydia is the most commonly diagnosed STI in the United States, and a separate study indicated that the total lifetime direct medical cost of chlamydia was $516.7 million in 2008.  

“Many chlamydia infections are identified through screening, which is frequently offered to females concomitantly with cervical cancer screening. Recent cervical cancer screening guidelines recommend screening less frequently and starting later,” Michelle S. Naimer, MD, MHSc, department of family and community medicine, University of Toronto, and colleagues of the new study wrote. “We sought to evaluate the impact of the … cervical cancer screening guideline change on Pap and chlamydia trachomatis (chlamydia) testing and incidence.”

According to the researchers, the U.S. Preventive Services Task Force and the American Cancer Society recommended in March 2012 that women aged 21 to 65 years be screened for cervical cancer every 3 years and that screening for women younger than 21 years be discontinued. Two agencies in Canada — Cancer Care Ontario and Canadian Task Force on Preventive Health Care — followed suit less than a year later.

Naimer and colleagues used population-based physician billing claims data from all females and males in Ontario aged 15 to 29 between May 2010 and July 2014 to identify Pap and chlamydia tests. They then utilized public health surveillance data to identify chlamydia cases. They conducted an interrupted time series analysis of quarterly data spanning both 2 years before and after the guideline change and fitted segmented linear regression or rational functions to the outcomes using autoregressive integrated moving average models. Results were arranged by age group and sex.

Researchers found that before the guideline changes, annual Pap testing rates were higher for older females and chlamydia testing rates were 4.6- to 6.5-fold higher for females than males. Chlamydia incidence was also higher among females and the incidence was highest among those aged 20 to 24 years, for both males and females. Pap testing declined in all age groups after the guideline release, with the greatest reduction among females aged 15 to 19 years. Since older females had higher baseline rates, the absolute decreases were larger for older age-groups, according to the researchers.

In addition, after the guideline changes, Naimer and colleagues found that chlamydia testing also decreased for all females, with the greatest reduction in the 15 to 19 years age group. In contrast, researchers observed small increases in chlamydia testing among males aged 20 to 24 years and 25 to 29 years 2 years after the guideline changes, as well as decreases in reported chlamydia incidence for females aged 15 to 19 years and 20 to 24 years, but not 25 to 29 years. Rates were unchanged for males.

“This study highlights the need to separate STI screening recommendations for females from cervical cancer screening recommendations. The [ACP’s] recommendation against screening pelvic examinations in asymptomatic and nonpregnant women could also potentially impact chlamydia screening rates in females if other screening practices are not adopted,” researchers wrote. “The USPSTF recently released new chlamydia screening recommendations. Screening for chlamydia with a [nucleic acid amplification testing] is recommended for all sexually active women aged 24 years or younger, and older women at risk. Canadian guidelines recommend screening at-risk groups (sexually active women and men aged 25 years or younger, older women at risk, and pregnant women) with [nucleic acid amplification testing] for urine, urethral, or cervical specimens.”

Naimer and colleagues also indicated that “effective” ways to increase screening in primary care include self-collected vaginal swabs, staff education, providing urine collection containers to patients at registration, and setting prompts built into electronic medical record systems to alert physicians to order certain tests such as chlamydia screening for a sexually active woman who is less than 25 years old. – by Janel Miller

Reference: CDC Web Page on Chlamydia (accessed 07-10-17)

Owusu-Edusei Jr K, et al. Sex Transm Dis. 2013;doi:10.1097/OLQ.0b013e318285c6d2.

Disclosure: The researchers report no relevant financial disclosures.