The American Journal of Managed Care February 2016
Longitudinal Adherence to Colorectal Cancer Screening Guidelines
Objectives: To describe adherence with United States Preventive Services Task Force (USPSTF) colorectal cancer (CRC) screening recommendations over a 10-year period in a large, continuously insured screening population at average risk for CRC.
Study Design: Retrospective claims database analysis.
Methods: Insured members (N = 151,638) who turned 50 years old between January 1, 2000, and December 31, 2004, and were at average risk for CRC were included in the analysis. Subjects were categorized as adherent, inadequately screened, or screening-naïve based on their level of adherence with USPSTF CRC screening guidelines. Outcomes considered were age at initial CRC screening and CRC screening tests received over the 10-year period.
Results: Of the 151,638 subjects in the cohort, only 97,518 (64%) were adherent with current CRC screening recommendations. An additional 18,050 (12%) were considered inadequately screened and 36,070 (24%) were screening-naïve. In those subjects who received some form of CRC screening, the average age at screening initiation was 53 years—3 years past the age recommended by current guidelines. Of those subjects who were inadequately screened, nearly half (46%) received only 1 fecal occult blood or fecal immunochemical test over the 10-year period.
Conclusions: In a sample of continuously insured average-risk individuals aged 50 to 54 years, CRC screening was initiated later and performed less frequently than recommended in USPSTF guidelines.
Am J Manag Care. 2016;22(2):105-111
- Longitudinal adherence to current United States Preventive Services Task Force colorectal cancer (CRC) screening recommendations was evaluated in a large population of continuously insured individuals at average risk for CRC.
- Only 64% of subjects were adherent to current CRC screening recommendations.
- Average age at screening initiation with any test was 3 years past that recommended by guidelines.
CRC places a substantial burden on healthcare systems, primarily due to detection in later stages. Forty percent of US patients diagnosed with CRC between 2004 and 2010 had localized disease, for which the 5-year relative survival rate was 89.8%, while 20% of patients had metastatic CRC, which has a 5-year relative survival rate of only 12.9%.6 The burden of CRC is largely preventable through early detection and removal of abnormal growths before symptoms develop.7 Furthermore, CRC treatment costs are lower when patients are diagnosed in earlier stages of disease.8
Evidence-based CRC screening guidelines developed by the United States Preventive Services Task Force (USPSTF) in 2008 recommend that adults at average risk for CRC begin screening at age 50 and continue until age 75 with either high-sensitivity fecal occult blood test (FOBT) or fecal immunochemical test (FIT) annually, flexible sigmoidoscopy (FS) every 5 years with a high-sensitivity FOBT every 3 years, or colonoscopy every 10 years.9 USPSTF guidelines do not recommend any of the above strategies over the others, but direct patients to use a routine CRC-screening strategy. These guidelines are aligned with recommendations by other US professional organizations, such as the Institute for Clinical Systems Improvement10 and the American College of Radiology.11
Although it is widely accepted that early detection through CRC screening provides the best potential to reduce the clinical and economic burdens of CRC,12-14 the effectiveness of CRC screening is limited by low uptake and adherence. In fact, 1 in 3 eligible individuals are not appropriately screened for CRC.15 Despite the fact that CRC screening rates have slowly and steadily increased over the last few decades in the United States, only 65.1% of adults had up-to-date screening—well below the national target of 80% by 2018,16 and lower than for other screening-amenable cancers, such as breast (72.4%) and cervical (83%).17
While several studies have assessed CRC screening behavior,18-21 very few US population-based studies have evaluated longitudinal adherence to CRC screening guidelines.22-24 Data from these longitudinal studies are less recent and may not reflect current adherence to CRC screening guidelines. In addition, some studies have used shorter time frames, which could lead to an underestimation of CRC screening adherence, especially for individuals choosing colonoscopy every 10 years as their periodic screening strategy.24
The objective of this analysis was to describe the longitudinal adherence with USPSTF-recommended CRC screening over a 10-year period in an average-risk CRC screening population continuously enrolled in commercial health plans. We suspected that a longer study time frame would not reveal improved longitudinal adherence to CRC screening guidelines.
This was a retrospective analysis of patient-level data from a large, national US administrative health claims database (Clinformatics DataMart, affiliated with Optum) containing records for medical, pharmacy, and laboratory services. The database contains more than 111 million unique commercial and Medicare members, with 12.1 million members having 5 or more years of continuous enrollment in 2008-2012, and it is geographically diverse across the United States, with greatest representation in the south and midwest US Census regions. Medical (professional, facility) claims include International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) diagnosis codes and procedure codes; Current Procedural Terminology, version 4, procedure codes; Healthcare Common Procedure Coding System procedure codes; site of service codes; provider specialty codes; and health plan and patient costs. All data were de-identified and accessed in compliance with the Health Insurance Portability and Accountability Act (HIPAA). No identifiable protected health information was extracted or accessed during the course of the study and the database used in this study has been certified as de-identified. Pursuant to HIPAA, the use of de-identified data does not require institutional review board approval or waiver of authorization.25
All individuals who turned 50 years old between January 1, 2000, and December 31, 2004, and had continuous medical eligibility for at least 10 years, beginning with the year that they turned 50, were included and tracked over this 10-year period. Individuals who had claims for CRC screening prior to the year they turned 50 were excluded, including those with any claims for colonoscopy (screening or diagnostic), FS, FIT or FOBT, double-contrast barium enema (DCBE), or computed tomographic colonography (CTC) tests. Additionally, individuals with evidence of high-risk history were excluded, including those with any of the following: a diagnosis of cancer prior to the index CRC screening test (ICD-9-CM diagnosis codes: 153.x,154.0, 230.3, 230.4, 230.7, 211.3, 211.4, 211.9, 235.2, 239.0), a personal history of colorectal polyps (V12.72), a personal history of cancer (V10.9), a family history of gastrointestinal cancer (V16.0), Crohn’s disease (555.1, 555.9), or ulcerative colitis (556).
Included subjects were classified as adherent, inadequately screened, or screening-naïve, based on alignment with current USPSTF screening guidelines.9 Subjects categorized as adherent had at least 1 colonoscopy claim, or at least 2 FS claims, or 1 FS and 5 annual FIT/FOBT test claims (FS and FIT/FOBT could occur in the same year), or 1 FIT/FOBT test claim per year over the 10-year observation period. Subjects categorized as inadequately screened had only 1 FS claim or fewer than 10 annual FIT/FOBT test claims over the 10-year observation period. Screening-naïve subjects had no claims for a CRC screening test over the 10-year observation period. Receipt of DCBE or CTC was not considered in this study, as these tests are not recommended by current USPSTF guidelines.9
The number and proportion of subjects 50 years or older who were adherent with CRC screening guidelines were assessed. Additionally, the average age at initiation of CRC screening and the types of CRC screening tests received were assessed. Within the adherent subgroup, the most common screening strategy received and the age at first colonoscopy were assessed. In inadequately screened subjects, the average number of FIT/FOBT tests received, and the utilization of FIT/FOBT and FS over the 10-year period were determined.
Subject characteristics were analyzed descriptively using t tests for continuous variables and χ2 tests for dichotomous variables. Descriptive statistics (mean, median) were computed for all outcomes. The data analysis for this paper was generated using SAS version 9.2 (SAS Institute, Cary, North Carolina).
As depicted in the Figure, of the roughly 5.8 million enrollees who turned 50 years old between January 1, 2000, and December 31, 2004, 265,796 had continuous medical eligibility for at least 10 years, beginning with the year that they turned 50. Of these, 151,638 were eligible for inclusion in the cohort (ie, they were neither high-risk nor screened prior to age 50).
Subject characteristics for the entire cohort and by adherence category are presented in Table 1. In the overall cohort, most subjects were commercially insured (98.9%) and only a small number of patients (1.1%) aged less than 61 years were insured through Medicare for disability reasons. Just under half of all subjects were male (47.4%) and the majority of subjects lived in southern (38.8%) or midwestern states (30.5%). For 45% of subjects, race was unknown; for the remainder, 45% were Caucasian, 4.9% African American, 3.7% Hispanic, and 1.4% Asian. Over the 10-year observation period, 97,518 (64.3%) subjects were adherent to USPSTF CRC screening recommendations; 18,050 (11.9%) were screened, but not adherent to screening recommendations (inadequately screened); and 36,070 (23.8%) were screening-naïve. There was no significant difference between the proportion of males and females who were adherent (64.5% vs 64.2%; P = .22); however, a significantly greater proportion of females than males were inadequately screened (14.3% vs 9.2%; P <.001) and a significantly greater proportion of males than females were screening-naïve (26.3% vs 21.5%; P <.001).
Subjects could be considered adherent based on more than 1 screening strategy. Of the 97,518 adherent individuals, 97,081 (99.6%) were adherent because they received at least 1 colonoscopy; 1946 (2%) were because they received at least 2 FS tests; 614 (0.6%) were because they received at least 1 FS test and at least 5 years of FIT/FOBT tests; and 268 (0.3%) were because they received at least 1 FIT/FOBT test per year over the 10-year observation period.
Of the 18,050 inadequately screened individuals, 773 (4.3%) were inadequately screened because they received only 1 FS test and no annual FIT/FOBT tests, 371 (2.0%) because they received 1 FS test and between 1 and 4 annual FIT/FOBT tests, and 16,906 (93.7%) because they received no FS test and fewer than 10 annual FIT/FOBT tests over the 10-year study period. Nearly half (8330 of 18,050; 46%) of inadequately screened subjects received just 1 annual FIT/FOBT test (with or without a FS test) over the 10-year period. Inadequately screened subjects received a mean of 2.6 annual FIT/FOBT tests over the 10-year study period.
Table 2 shows the distribution of ages when subjects in the cohort received their first CRC screening test. The mean and median age at the time of first CRC screening test were 53 and 52 years, respectively, for both the adherent and inadequately screened subgroups. Almost half (47,085 of 97,081; 49%) of subjects who were adherent because they received at least 1 colonoscopy had their first colonoscopy after age 53 (Table 3).