Abstract 2579: Longitudinal predictors of adherence to cervical cancer cotesting guidelines
Authors: Rendle Katharine A. , Schiffman Mark , Cheung Li C. , Kinney Walter K. , Fetterman Barbara , Poitras Nancy E. , Castle Philip E. 
Published: July 2016

Abstract
Introduction: Although clinical guidelines recommend cervical cancer screening using human papillomavirus (HPV) combined with Papanicolaou (Pap) testing for average-risk women, little is known about the longitudinal adoption of cotesting in clinical care, or if interval extension resistance is evident in practice. Using data from Kaiser Permanente Northern California (KPNC), which switched from annual Pap to 3-year interval cotesting in 2003, we examined predictors of cotesting guideline adherence.
Methods: We included all female patients aged 30-64 years who underwent baseline cotesting between 2003-2007 and completed at least one additional screening within 5.5 years. We excluded patients with a documented history of &gt;CIN2, or positive HPV test at baseline or subsequent screenings (leaving 335,822 patients for analysis). We categorized interval length between cotesting into 3 categories: early (&lt;2.5 years), adherent (2.5-3.5 years), and late (3.5-5.5 years). We used multinominal logistic regression models to examine the association (adjusted odds ratio [aOR]) between interval length from baseline cotesting to first follow-up cotesting (Interval 1) and the following predictors assessed at baseline: year of first cotesting, age, previous hysterectomy, and previous low-grade abnormal pap (&lt;CIN2). We also examined predictors of persistent early screening in women classified as early screeners in both Interval 1 and Interval 2 (defined as time between first and second follow-up cotesting).
Results: Compared with the earliest cohort of women (baseline cotesting in 2003), the 2007 cohort was 66% and 52% less likely of being screened early (aOR = 0.34, 95% CI: 0.33, 0.35) or late (aOR = 0.48, 95% CI: 0.46, 0.50). However, among women classified as persistent early screeners, we found no clear trend in the relationship between year of initial cotesting and interval length. The strongest predictor of persistent early screening was older age, whereby women aged 60-64 years had the greatest likelihood of being a persistent early screener (aOR = 2.1, 95% CI: 1.9, 2.3) versus women aged 30-34 years. Despite subsequent negative screens, women reporting a previous low-grade abnormal Pap at baseline had a greater likelihood of being a persistent early screener compared with women who did not (aOR = 1.8, 95% CI: 1.6, 2.0).
Conclusions: Overall, women who underwent baseline cotesting in more recent years were significantly more likely to adhere to the recommended interval length than women in earlier years, indicating an increase in adoption of cotesting guidelines over time. However, there remain subgroups, including older women, which appear less likely to follow extended cotesting intervals. Further research is needed to understand these HPV screening practices in other healthcare settings and identify additional (potentially modifiable) patient and provider factors that are associated with screening practices.
Citation Format: Katharine A. Rendle, Mark Schiffman, Li C. Cheung, Walter K. Kinney, Barbara Fetterman, Nancy E. Poitras, Philip E. Castle. Longitudinal predictors of adherence to cervical cancer cotesting guidelines. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2579.