Adherence and the Economics of Colon Cancer Screening
Condition: Colorectal Cancer Screening
MeSH terms: Colorectal Neoplasms
Study type: Observational

Summary: 
      This study will compare patient adherence to different colorectal cancer (CRC) screening
      tests to identify the most cost-effective strategy to decrease mortality from CRC. We
      hypothesize that different types of tests will have different adherence rates, that these
      rates will alter the cost-effectiveness analysis, and that we can identify patient variables
      associated with non-adherence to specific CRC screening strategies.
    

Detailed description: 
      Colorectal cancer (CRC) is a significant and preventable disease, yet CRC screening rates
      remain low. Previous investigators have identified barriers to adherence to CRC screening;
      however, the majority of data have been retrospectively derived, and the limited data
      produced from prospective assessment have been limited to fecal occult blood testing (FOBT).
      Constructs based on the Health Belief Model have been proposed to identify items associated
      with non-adherence to CRC screening, but prospective validation of this model is lacking. The
      U.S. Preventive Services Task Force report cites a major cause of uncertainty for calculation
      of the incremental cost-effectiveness of CRC screening is the deficit in primary data
      regarding adherence to CRC screening tests, specifically whether heterogeneity exists in
      screening rates of competing strategies. The Institute of Medicine confirmed the importance
      of detecting heterogeneity in adherence between strategies, understanding that some
      strategies currently recommended for CRC screening may be dominated by strategies that
      achieve greater levels of adherence.

      This study aims to determine whether adherence rates to CRC screening are heterogeneous
      between competing strategies (FOBT and colonoscopy). This study will also prospectively
      examine domains of the Health Belief Model to identify associations with non-adherence to
      screening. Adherence rates specific to tested strategies will be incorporated in our existing
      economic models to compare the incremental cost-effectiveness of competing CRC screening
      strategies. These data will greatly impact policy decisions regarding resource allocation for
      CRC screening. It is also expected that future research based on data generated through this
      project will aim to develop and test interventions that optimize adherence to screening
      strategies to decrease mortality from CRC.

      Procedures:

      Patients who are due for CRC screening and meet eligibility requirements are identified
      through a query of the electronic medical record database at San Francisco General Hospital
      (SFGH). A research assistant (RA) obtains the PCP's approval to attempt recruitment at the
      patient's primary care appointment. The PCP discusses CRC screening with the participant
      during their regularly scheduled appointment.

      Availability of CRC screening tests: Because of capacity constraints in the endoscopy unit at
      SFGH, the screening method for those at average risk of CRC had been limited to annual fecal
      occult blood testing (FOBT). However, the gastroenterology department initiated a pilot
      program which allows different primary care clinics to refer average-risk patients for
      colonoscopy screening in rotating 3-month time-blocks. To ensure the endoscopy unit has
      sufficient capacity to provide CRC screening via colonoscopy, providers in a given primary
      care clinic are able to refer their patients for (a) colonoscopy screening, (b) FOBT
      screening, or (c) a choice of either colonoscopy or FOBT screening, depending on the time
      block. This is not a study intervention; providers simply recommend that their patients
      complete a standard CRC screening test, and discuss the option or options available. Patients
      who decline to participate in the study undergo colorectal cancer screening under the
      guidance of their primary care provider; the same screening tests are available to those who
      participate and those who do not.

      After giving written informed consent, participants complete an RA-administered 20-minute
      survey based on constructs of the Health Belief Model. Participants also grant us approval to
      review their medical records in one year to determine if they complete screening; those
      without a record of testing are contacted to determine if they completed testing outside of
      SFGH.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        General population of users of outpatient primary care clinics at San Francisco General
        Hospital at average risk for development of colorectal cancer (CRC). Outpatient clinics
        include the General Medical Clinic, the Family Health Center, and the Positive Health
        Program (HIV primary care clinic).
      
Keywords: Colorectal cancer (CRC); Colorectal cancer screening; Colonoscopy; Fecal occult blood test (FOBT); Cost-effectiveness