A population-based evaluation of cervical screening in the United States: 2008-2011

Abstract

Background: Cervical screening consumes substantial resources, but little is known about utilization in the United States or compliance with guideline recommendations.

Methods: To describe population screening coverage, utilization, and outcomes and examine time trends from 2008 to 2011, cervical cytology reports from women residing in New Mexico (981,063 tests from 511,381 women) were evaluated.

Results: From 2008 to 2011 cervical screening utilization decreased at all ages, but especially in younger women, with a two-third reduction at ages 15 to 20 years. Ninety-four percent of women ages 25 to 29 years were screened within 48 months but coverage decreased at older ages to 69% at 45 to 49 years and 55% at 60 to 64 years. Intervals between screening tests were significantly longer in 2011 compared with 2008 [HR = 1.23; 95% confidence intervals (CI), 1.22-1.24], although the commonest rescreening interval was 13 months. In 2011, 91.9% of screening tests for women ages 21 to 65 years were negative, 6.6% showed minor abnormalities, and 1.0% high-grade abnormalities. High-grade abnormality rates were relatively constant over time, but minor abnormalities and atypical cells cannot rule out high-grade (ASC-H) were increasing.

Conclusions: This population-based evaluation of cervical screening shows high coverage under the age of 40 years, but lower levels in older women. Screening under age 21 years is becoming less common and screening intervals are lengthening, reflecting updates in national screening guidelines.

Impact: Assessment of cervical screening intervals and population outcomes is essential for accurately estimating the impact and effectiveness of changing recommendations and vaccination against human papilloma virus infections.

Figure 1

Percent of New Mexico female population with a screening cytology test (Pap test) during a specific year by age group.

Figure 2

(A) Kaplan-Meier estimates for time since previous cervical screening test by year index test was performed with hazard ratios (HR) and 95% confidence intervals from Cox model regression analyses and (B) median time to last screening test by age group in the given year.

Figure 3

(A) Percent of women with different numbers of cervical screening tests by age (on 1 Jan 2008) between years 2008 – 2011. (B) Percent of women with at least one cervical screening test in the previous 18, 36 and 48 months before 1 January 2012 by age on 1 January 2012.

Figure 4

Screening interval distributions (months between cytology tests) among women with a screening test in 2011 and aged 21–29 (A) and 30–65 (B) years. The >48 months category includes women with no previous screening test.