Fecal immunochemical testing resulted in higher colorectal cancer screening rates than did guaiac fecal occult blood tests, with less dependence on office visits.
Published Online: October 24, 2012
Elizabeth G. Liles, MD, MSCR; Nancy Perrin, PhD; Ana Gabriela Rosales, MS; Adrianne C. Feldstein, MD, MS; David H. Smith, RPh, MHA, PhD; David M. Mosen, PhD, MPH; and Jennifer L. Schneider, MPH
Objectives: To compare completion rates of colorectal cancer screening tests within a health maintenance organization before and after widespread adoption of the fecal immunochemical test (FIT).
Study Design: Retrospective cohort study.
Methods: Using electronic medical records of 113,901 patients eligible for colorectal cancer screening, we examined test completion during 2 successive time periods among those who received an automated screening outreach call. The time periods were: 1) the “guaiac fecal occult blood test (gFOBT) era,” a 15-month period during which only gFOBT was routinely offered, and 2) a 9-month “FIT era,” when only a new FIT was routinely offered. In addition to analyzing completion rates, we analyzed the impact of practice-level variables and patient-level variables on overall screening completion during the 2 different observation periods.
Results: The change from gFOBT to FIT in an integrated care delivery system increased the likelihood of screening completion by 7.7% overall, and the likelihood of screening with a fecal test by 8.9%. The greatest gains in screening completion using FIT were among women and elderly patients. Completion of FIT was not as strongly associated with medical office visits or with having a primary care provider as was screening with gFOBT.
Conclusions: Adoption of FIT within an integrated care system increased completion of colon cancer screening tests within a 9-month assessment period,
compared with a previous 15-month gFOBT era. Higher completion rates of the FIT may allow for more effective dissemination of programs to increase colorectal cancer screening through centralized outreach programs.
(Am J Manag Care. 2012;18(10):588-595)
Dissemination of the fecal immunochemical test (FIT) resulted in higher colorectal cancer screening completion rates than were observed using the guaiac fecal occult blood test (gFOBT).
Visiting a healthcare provider may be less important for completion of screening with the use of FIT than with the use of gFOBT.
The FIT may enable broader adoption of centralized outreach programs for CRC screening.
Populations less inclined to screen with fecal tests, including women, the elderly, and those taking more medications may more readily complete screening when offered FIT than when offered gFOBT.
Colorectal cancer (CRC) is the second-leading cause of cancer death in the United States, and affects men and women almost equally.1-3 The US Preventive Services Task Force (USPSTF) recommends screening with any of 3 options, including fecal testing, flexible sigmoidoscopy, or colonoscopy. Screening for CRC with fecal occult blood testing done annually or biennially has been shown to decrease mortality from colorectal cancer by 15% to 33%, primarily through detection of early-stage cancers.4-9 The guaiac fecal occult blood test (gFOBT) has a known positive balance of benefit and risk in screening populations, is the least expensive screening method, and is preferred over endoscopy in 30% to 55% of patients.10-12 However, gFOBT has limitations in the areas of test adherence and test performance because testing requires dietary and medication restrictions during the 3 days that 3 separate stool samples are collected—a cumbersome protocol that can interfere with test completion.13
While adherence to test completion in the initial round of screening with gFOBT in 3 large randomized trials was 59% to 67%,5-7 smallerscale studies have demonstrated lower 1-time screening completion rates using gFOBT by 25% to 30%.14,15 Retaining patients in annual or biennial gFOBT screening programs has proved challenging, with observed rescreen rates of approximately 50% on a second round.9,16 The fecal immunochemical test (FIT) may improve upon these rates. Previous randomized studies have shown that adherence to 1-time completion of a 1-sample or 2-sample FIT is 10% to 12% greater than adherence to gFOBT, and that the sensitivity of FIT is equal to or greater than FOBT.14,15,17-19 A single (3-sample) gFOBT detects about 12% to 38% of cancers,20-22 whereas a 1-sample FIT detects 25% to 69% of cancers,22-24 and a 3-sample FIT detects 66% to 92% of cancers.22,24-27 As a result, in 2008, multiple professional societies endorsed the use of 4 types of FITs for colorectal cancer screening as a replacement for gFOBT in the United States.1,28 However, it remains unclear to what extent a transition from gFOBT to FIT will improve screening test completion in large community-based populations and which specific populations may benefit the most. We capitalized on a natural experiment by analyzing completion rates before and after the change from gFOBT to FIT.
The protocol for this study was approved by the institutional review board within the study health maintenance organization (HMO).
Study Site and Data Sources
The study was conducted at Kaiser Permanente Northwest (KPNW), a not-for-profit HMO in the Pacific Northwest with about 485,000 members. The membership of KPNW is similar to the local insured community.29 Electronic records and a patient survey described below provided clinician and patient data.
KPNW maintains a CRC screening clinical practice guideline based upon the recommendations of the USPSTF. Each of the USPSTF-recommended CRC screening modalities (ie, fecal testing, flexible sigmoidoscopy, or colonoscopy) is a covered benefit and available to patients, although fecal testing is encouraged through systemwide outreach efforts in lower-risk individuals. The study site has had an automated call CRC reminder program in place since January 2008; details of the patient selection process for outreach and of the automated call system have been published. The system targets averagerisk individuals who are not being actively treated for major diseases (eg, cancer), or receiving nursing home or hospice care.30 Each month, approximately 5000 eligible HMO members receive a telephone call with an offer for a fecal test to be sent to their home. Included in the mailed packets are the test, instructions, and a card stock envelope addressed to the KPNW laboratory for return. Those who request the test but do not complete it within 6 weeks receive up to 2 reminder phone calls, 6 weeks apart.
In April 2009, KPNW switched from sending the 3-sample gFOBT to sending a single-sample FIT that required no dietary or medication restrictions—the OC -Micro FIT (Polymedco, Cortland Manor, New York).
Study Design Overview
The retrospective cohort study examined colorectal cancer screening test completion among those receiving an automated telephone call (ATC) during 2 successive time periods: 1) The “gFOBT era,” a 15-month period during which the gFOBT was routinely offered through ATC outreach, and 2) a 9-month “FIT era.” We also analyzed the impact of practicelevel variables (eg, primary care provider [PCP] assignment, primary care utilization, and specialty care utilization) and patient-level variables (eg, age, gender, number of medications, body mass index [BMI], and length of HMO membership) on overall screening completion during the 2 different observation periods.
Additionally, we mailed a survey to 2000 patients who received an ATC during 1 or both time periods. This survey was designed to understand the barriers and facilitators that patients encountered in their efforts to complete colorectal cancer screening. For the purposes of this analysis, we discuss the specific answers among only those respondents who answered questions about both tests, because they had had prior experience with each type of fecal test.
This retrospective cohort study was conducted in 2 phases. The Figure outlines the study population flow.
Cohort Population: The cohort consisted of HMO members aged 50 to 80 years who were overdue for CRC screening at the beginning of each month of an observation period, and who received an ATC from the CRC screening outreach program at KPNW.
We utilized 2 observation periods: 1) The “gFOBT era”—a 15-month period during which the gFOBT was routinely offered through ATC outreach from January 1, 2008, through March 31, 2009 (n = 59,876); and 2) a corresponding “FIT era” from April 1, 2009, through December 31, 2009 (n = 32,601), excluding a single month (September 2009) in which KPNW was piloting a different type of ATC vendor.
Survey Sample: Patients eligible to receive the survey about their experiences with both gFOBT and FIT included HMO members who had received an ATC for CRC screening between March and June 2009, had a PCP, and had no diagnosis of dementia in their electronic medical record (EMR). Of a total eligible population of 8077, we mailed the survey to 2000 randomly selected adults; of this population, 1816 (90.8%) were contacted. Reasons for non-contact included incorrect phone numbers and/or addresses; 48.6% (N = 883) responded. We analyzed responses from 192 patients who had previously received both types of fecal tests and answered questions about barriers and facilitators of fecal test completion.
Survey Design. We included questions both from known validated prior questionnaires and questions that we designed in order to improve understanding of issues that emerged from 4 individual patient interviews. Interviewed patients were selected from lists of patients of PCPs at KPNW who had either the highest screening rates or the lowest screening rates. All 4 patients who agreed to be interviewed had completed screening. Two had higher screening rate PCPs and 2 had lower screening rate PCPs. Interviewees shared their beliefs about and knowledge of colorectal cancer and their perceived individual risk for cancer. Domains of the questionnaire included validated questions about beliefs, worries, and knowledge about CRC screening,31-36 experiences with specific CRC-screening tests, experiences with healthcare providers and members of the healthcare team,37,38 and perceived barriers and facilitators to CRC screening completion.13,39-42
The subset of survey respondents (N = 192) who answered specific questions about both gFOBT and FIT used a Likert scale (1 indicating strong agreement and 5 indicating strong disagreement) to answer questions about specific test perceptions and experiences of gFOBT and FIT (Table 1).
Study Variables for Cox Proportional Hazards Regression. We extracted the following variables from the EMR: The primary outcome of CRC screening completion (any of gFOBT, FIT, flexible sigmoidoscopy, colonoscopy, or dual contrast barium enema) within 9 months of an ATC, demographic variables (age at the time the ATC was received, gender, race/ethnicity—derived from electronic databases, with missing data geocoded using the census tract block corresponding to each patient’s mailing address), health characteristics (BMI, number of active medications at the time of ATC receipt), “era” (whether they received the gFOBT or FIT as part of the ATC outreach program), and, lastly, the variables describing encounters with the healthcare system. These latter variables included length of KP membership (by 3 years), whether the participant had a PCP (vs none), and whether they had visited their PCP (vs no PCP visit) or a different PCP (vs no “other” PCP visit) within 9 months of the ATC. Healthcare encounters also included visits with medical specialists (vs no visit) or with “other” specialists (eg, orthopedic surgery, neurosurgery, optometry) within 9 months of the ATC (vs no “other” specialty visit).
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