: Despite recommendations for triennial cervical cancer screening for low-risk women aged 30 years and older, annual screening remains common. We studied how often women receiving care from an academically affiliated medical group were screened, and patient and provider factors associated with overuse and underuse. We also explored the impact of changing measurement intervals on computed screening frequency.

: The study included women aged 30 years and older continuously enrolled over a 3-year period and excluded women with history of abnormal screening and conditions of high risk for cervical cancer.

: Administrative and laboratory data were merged to link Papanicolaou (pap) test results with patient and ordering provider characteristics. We used logistic regression to analyze multivariate models for overuse and underuse, and modified measurement intervals to test sensitivity to early and late pap smears.

:The 8018 women had a mean age of 48 years and 95% had an ambulatory physician visit during the observation period. Thirty-four percent of women received guideline-based screening, 45% had overuse, and 21% had underuse. Factors independently associated with overuse included younger age, more medical visits, contraceptive management visits, and gynecology provider specialty. Underuse was associated with older age, fewer medical visits, and increased comorbidity. Overuse was 47% if unsatisfactory paps were not considered and was reduced to 35% if the observation interval was reduced from 36 to 30 months.

: Overuse and underuse of cervical cancer screening are common, and clinician and patient factors are identifiable to target quality improvement interventions. Modifying the measurement interval may improve the measure.

For a decade, US medical professional organizations

 and the US Preventive Services Task Force (USPSTF)

 have suggested that low-risk women (history of multiple normal Papanicolaou [pap] tests, age over 30 years) receive cervical cancer screening every 3 years as part of routine preventive services. Prior to these guidelines, observational and case control studies supported similar clinical outcomes between 1- and 3-year intervals.

 However, surveys showed that most (60-70%) gynecologists and primary care providers continued to perform annual screening, and many were unaware of the new guidelines.

 Recently, the USPSTF solidified its recommendations for the 3-year interval,

 and they and the American College of Obstetricians and Gynecologists suggest a 5-year interval with negative HPV testing.

A 2010 study using the National Ambulatory Medical Care Survey projected that triennial screening would reduce testing by 6.3 million pap tests per year and reduce costs by $403.8 million.

 An earlier study projected that an additional 69,665 pap smears and 3861 colposcopies would need to be performed in women 30 to 44 years of age to avert one case of cervical cancer by screening every year instead of every 3 years. For women 45 to 59 years old, 209,324 pap tests and 11,502 colposcopies would need to be performed.4 Using National Health Interview Survey data, projected compliance with triennial screening would decrease the anannual number of pap smears from 75 million to 34 million.

Since 2009, a pay for performance measure has been applied to managed care plans in California to encourage triennial rather than more frequent screening, but there has been little exploration of cervical cancer screening rates in populations affected by this measure. Furthermore, preventing overuse might encourage underuse, so both should be simultaneously evaluated. To encourage targeted use of screening, understanding physician and patient factors associated with overuse and underuse is needed.

We evaluated usage of cervical cancer screening in one medical group’s patients with the goal of identifying factors amenable to intervention. In addition, we varied the time period of the 3-year measure and accounted for clinically insufficient pap tests to evaluate the proportion of patients that were close to receiving appropriate screening to test the clinical applicability of the measure, which is important in order to promulgate interventions with clinicians.

We evaluated cervical cancer screening provided to female patients in an academic medical center—affiliated group (commercial health maintenance organization [HMO] and Point of Service enrollees). We linked laboratory data for pap smear pathology with patient encounter data and then linked this with patient general claims data and administrative records for physicians in order to link testing patterns to patient and physician characteristics. After categorizing cervical cancer screening patterns, multivariate models were constructed to identify factors independently associated with screening overuse and underuse.

Eligible female patients were women aged 30 years and older continuously enrolled with the practice from January 1, 2007, to December 31, 2009. The study population was refined using the following exclusion criteria: (1) ICD-9 codes for cervical or endometrial cancer or DES exposure, any grade of cervical dysplasia (CIN) or abnormal cervical cytology (ASCUS, ASC-H, LSIL, HSIL, AGC) or HPV infection, and high-risk conditions for cervical cancer (HIV infection, leukemia, neutropenia, history of organ transplantation); and (2) CPT codes for procedures related to abnormal cervical cytology (colposcopy, LEEP, or cryotherapy). These criteria were applied during the study period and the preceding 3 years.

Pathology results were available for every pap smear performed on a patient, which also identified the ordering provider. The text of the cytology result was analyzed to identify and eliminate unsatisfactory pap smears. Characteristics of ordering providers were collected from an online physician database maintained by the health system. The UCLA Institutional Review Board approved the study.

Each patient in the study population was assigned a cervical cancer screening category, based on the total number of satisfactory pap smears performed during the 36-month observation period. Assignment of category accounted for age and whether a woman had a hysterectomy. Pap smears deemed inadequate for histologic evaluation were excluded from analysis. The three cervical cancer screening categories were: (1) Underuse—0 screening episodes for a woman with a uterus (measure not applicable for age greater than 67 years); (2) Guideline-consistent use&mdash;exactly 1 screening episode over the 3-year observation period for a woman with a uterus (0 or 1 acceptable for women over 67 years) or 0 screening episodes for a woman without a uterus; and (3) Overuse&mdash;2 or more screening episodes for a women with a uterus or 1 or more screening episodes for a women without a uterus.

Using billing data, we collected patient age (at study entry), race/ethnicity (Asian/Pacific Islander, Hispanic, non-Hispanic black, non-Hispanic white, and non-Hispanic other), and preferred language (English, Spanish, or other). Age was subdivided into three categories (30-50 years, 51-70 years, 71 years and older). In cases where ethnicity information was missing (5.9%), non-Hispanic was assigned, as this was the modal condition (82%). Using billing and encounter data, we also collected total outpatient visits over the observation period (categorized as 1-10 and greater than 10), presence of comorbidities (diabetes, coronary artery disease, hypertension, cerebrovascular disease, and depression), average total Medicare Risk Adjustment Factor (RAF) score (which reflects patient complexity and illness severity), any visits for contraceptive management over the observation period, and for women over 40 years of age, number of mammograms received during the 3-year interval.

Utilizing the laboratory data link to physician, we derived a variable describing specialty mix of ordering providers for all pap smears performed on each patient (primary care only, gynecology only, primary care and gynecology, neither primary care nor gynecology). We collected information on the gender of provider, years since medical school graduation, and clinical specialty. We also included a variable indicating whether a provider attended a medical group—sponsored CME meeting about cervical cancer screening guidelines.

We described patient characteristics and computed for each patient her cervical cancer screening category. We compared patient characteristics across the three screening categories using Pearson’s χ2 and simple logistic regression, as appropriate. We also examined distribution of screening category by pap smear provider specialty mix. All analyses were performed using SAS version 9.2 (SAS Institute, Cary, North Carolina).

We separately evaluated predictors of overuse compared with guideline use and underuse compared with guideline use, using hierarchical logistic regression. The underuse model contained only patient characteristics because no pap provider existed. These models included the following patient characteristics (described above): age, race/ethnicity, language (English and non-English), greater than 10 outpatient visits over the study period (versus 10 or less), RAF score, comorbid conditions, and whether the patient had a visit for contraception. The overuse model included each of these variables plus provider gender, specialty, attendance at a cervical cancer screening CME lecture, and greater than 8 years in practice. For the overuse model, we carried out a subanalysis for women aged 40 years and older that added mammogram count. This analysis aimed to understand whether adherence to one guideline was associated with adherence to another or whether screening was performed in a regular, non-targeted fashion.

We performed an analysis to understand how sensitive the triennial measure is to pap smears performed at the extremes of or just outside of the measurement period. An additional 6 months of data were collected from January 1, 2010, to June 30, 2010. Alternate observation periods of 30 months (January 2007 to June 2009) and 42 months (January 2007 to June 2010) were used to recompute the cervical cancer screening category for each patient. In order to evaluate the effect of a pap smear being performed late and just outside the 3-year interval, we compared underuse rates in the 42- and 36-month study intervals. In order to evaluate the effect of a pap smear being performed early and just inside the 3-year interval, we compared overuse rates in the 30- and 36-month study intervals. In order to evaluate the secular trend, we compared overuse and underuse in the original 36-month window (January 1, 2007, to December 31, 2009) with the 36-month window of July 1, 2007, to June 30, 2010. The multivariate analysis was repeated to examine the effect of changing observation period on the multivariate results.

There were 10,111 women continuously enrolled with the medical group from January 1, 2007, to December 31, 2009. After exclusions were applied, 8018 women remained in the sample. Laboratory data from the study period showed that 10,998 pap smears were performed on this group of 8018 women. A total of 450 unsatisfactory test results were removed from the analysis. The final laboratory sample had 10,548 unique pap smear results. These tests were performed by 166 providers (see 

Fifty-four percent of the 8018 women were 50 years or younger (mean, 48 years; standard deviation [SD]=10.5; range, 30-91 years). Over half were white non-Hispanic ethnicity and 16.5% were Asian/Pacific Islander. Nearly all women were Englishspeaking. Ninety-five percent had at least one outpatient clinic visit, with an average of 16 visits over the 3-year study period (SD=15; range, 1-186 visits). Most visits were to primary care providers.

		Table 1. Demographic and Clinical Characteristics of Study Patients, Overall and by Cervical Cancer Screening Category

Articles

For a decade, US medical professional organizations and the US Preventive Services Task Force have suggested that low-risk women (history of multiple normal Papanicolaou [pap] tests, age over 30 years) receive cervical cancer screening every 3 years as part of routine preventive services. 

Neil S. Wenger, MD, MPH

Articles

Cervical Cancer Screening Overuse and Underuse: Patient and Physician Factors