Despite strong evidence for the effectiveness and cost-effectiveness of a variety of colorectal cancer (CRC) screening methods for reducing CRC mortality, current CRC screening rates fall far below the levels needed to significantly impact CRC mortality. Unfortunately, however, the existing literature on patient CRC screening behavior does not yet provide a sufficient evidence base for making sound recommendations regarding how to most effectively improve upon these rates in the VA. This study will inform future CRC screening promotion efforts and make important scientific contributions to existing literature by: (a) delineating the relative contribution of patient cognitive, environmental and background factors to CRC screening behavior using a multi-level, theory driven analysis approach on a nationally representative sample, and (b) identifying the determinants of variation in CRC screening behavior across vulnerable population subgroups.

Background / Rationale:

Despite strong evidence for the effectiveness and cost-effectiveness of a variety of colorectal cancer (CRC) screening methods for reducing CRC mortality, current CRC screening rates fall far below the levels needed to significantly impact CRC mortality. Unfortunately, however, the existing literature on patient CRC screening behavior does not yet provide a sufficient evidence base for making sound recommendations regarding how to most effectively improve upon these rates in the VA. This study will inform future CRC screening promotion efforts and make important scientific contributions to existing literature by: (a) delineating the relative contribution of patient cognitive, environmental and background factors to CRC screening behavior using a multi-level, theory driven analysis approach on a nationally representative sample, and (b) identifying the determinants of variation in CRC screening behavior across vulnerable population subgroups.

Objective(s):

The overall goal of this study was to address significant gaps in the existing evidence base in order to inform the development of effective patient-directed interventions to increase CRC screening among veterans age 50 and older. This was accomplished by using data collected from a mailed patient survey and theory-based analysis approaches to uncover key barriers to screening adherence and to identify fruitful intervention approaches for modifying them. The specific primary objectives of this study were to: (1) Estimate the relative effect of patient cognitive (knowledge, attitudes, and self-efficacy), environmental (social network and medical care characteristics), and background (demographics, health status, prior screening experiences) factors on CRC screening behavior; (2) Identify factors that contribute to any disparities in CRC screening behavior by race/ethnicity or other patient characteristics; (3) Identify from these analyses: (a) priority population subgroups to target in future interventions (i.e., those at the greatest risk of failing to be screened), and (b) priority factors to target in future interventions (i.e., those that are not only strongly associated with CRC screening but also prevalent in the target population and amenable to intervention, as well as those that are most likely to ameliorate race and other disparities). Secondary objectives included: (1) assessing patient values and preferences regarding the various CRC screening modality options, (2) estimating stage of readiness to adopt CRC screening in the study population, and (3) validating measures of CRC knowledge and self-reported screening behavior.

Methods:

This is an observational study based on a nationally representative, cross-sectional mailed survey of 3,744 male and female veterans age 50-75 who have had one or more primary care visits at a VA Medical facility in the past two years. The survey sample was drawn using a two stage procedure where we first randomly select 24 VA facilities stratified by size and racial mix and then select a simple random sample of 156 eligible veterans from each sampled facility. Prior to the national survey, a pilot survey was conducted with the purpose of refining both the study instruments and the study protocol. The sample consisted of 900 randomly selected veterans from the Minneapolis VA Medical Center meeting the same sampling eligibility criteria used for the national mailed survey. The mailed patient questionnaire, made up primarily of previously validated measures, included measures of self-reported CRC screening behavior; patient demographic, health, social network and medical care characteristics; CRC screening knowledge, attitudes, social norms and self-efficacy; and attitudes toward medical care. Additional measures of organizational-level CRC screening practices from a recently completed VA facility survey were linked to the patient survey.The primary outcome is whether the patient is currently compliant with CRC screening guidelines (i.e., received either a fecal occult blood test in the past year, a sigmoidoscopy or double contrast barium enema in the past five years, or a colonoscopy in the past ten years). The primary analyses tested (using logistic regression and a multi-level, structural equation modeling approach) specific hypotheses about the association between this measure and patient background, cognitive and environmental factors and their interactions. Additional analyses conducted include a multinomial logistic regression to assess patient screening mode preferences and their determinants, and logistic and multinomial logistics regression analyses with interactions to determine whether and why any observed patterns in CRC screening behavior vary by race.

Status:

Completed

Inclusion Criteria:

Study subjects must be a male or female veteran who has had one or more primary care visits at a VHA medical center in the past 2 years and is between the age of 50 and 75.

Exclusion Criteria:

Study subjects cannot be a VHA employee, deceased, have a colorectal cancer diagnosis, be enrolled in VA adult day care or nursing home, or have dementia.

Primary care patients