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Correspondence: Address correspondence to Dr. Marvella E. Ford, Department of Biostatistics, Bioinformatics, and Epidemiology, Medical University of South Carolina, 135 Cannon Street, Suite 303, P.O. Box 250835, Charleston, SC 29425. E-mail: fordmar{at}musc.edu
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Abstract |
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Key Words: Case management • Cancer screening • African American men
The Need to Retain African American Men in Cancer Screening Trials
African American men tend to participate in cancer screening trials at low rates, despite having higher rates of cancer incidence and mortality than their Caucasian counterparts (Ford et al., 2003; Guo, Sigman, Borkowski, & Kyprianou, 2000; Platz et al., 1999; Powell et al., 2000; Quill & Brody, 1996; Stallings et al., 2000). Previous studies demonstrate that African Americans may be more likely than others to experience attrition when enrolled in clinical trials, although this finding appears to be confounded with income rather than related directly to race (Blumenthal, Sung, Coates, Williams, & Liff, 1995; Psaty et al., 1994). These higher rates of attrition in cancer screening trials lead to less screening data obtained from African American men. Without adequate numbers of African American men in cancer screening trials, the generalizability of study results to members of this population is in question.
Intervention Rationale
In our previous study designed to recruit older (aged 55 years and older) African American men to a cancer screening trial (Ford,1996; Ford et al., 1998; Ford et al., 2003; Stallings et al., 2000), participants stated that attempting to meet competing needs (such as the need for food or heat in their homes) hindered them from agreeing to participate when they were first contacted by study staff.
Previous research has shown that attrition of study participants is associated with having lower income compared with higher income (Nevid, Javier, & Moulton, 1996; Spoth, Goldberg, & Redmond, 1999). In the Baltimore Longitudinal Study of Aging, attrition was greater among people with less education, which may have been associated with lower income (Sharma, Tobin, & Brant, 1986). Therefore, we hypothesized that competing needs would more strongly affect the trial adherence of participants with fewer financial resources (i.e., lower income) than that of participants with greater financial resources.
Conceptual Framework
Case management principles formed the basis of the adherence trial designed to address participants' competing needs. For this study, we defined case management as outreach, service planning, service linkage, monitoring, and advocacy (Ferguson & Weinberger, 1998; Newcomer, Arnsberger, & Zhang, 1997). According to Cnaan (1994), one of the functions of case management is to link clients with needed services.
The case management intervention incorporated a conceptual framework developed by Swanson and Ward (1995). This framework addresses barriers to clinical trial participation among minorities. Sociocultural barriers refer to fear and mistrust of federally sponsored research. Economic barriers are the costs associated with participating in a research study. Individual barriers include denial of disease or feelings of disease invulnerability, and barriers inherent in study design refer to barriers intrinsic to the research design, such as requiring participants to get screened at study sites located in metropolitan areas where they do not feel comfortable (Swanson & Ward, 1995). During their interactions with study participants, case managers addressed competing needs related to these barriers.
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In our previous recruitment study, spouses or partners served as gatekeepers in terms of access to study participants (Ford, 1996; Stallings et al., 2000). Therefore, we included the spouses or partners of participants in the case management intervention in order to maximize access to participants. We accomplished this through the case managers, who asked to speak with each spouse or partner during the monthly telephone calls to each study participant. When speaking with the spouse or partner, the case managers let her or him know that the case managers were available to serve as resource contacts for the spouse or partner as well as for the participant.
The case managers grouped the services requested by study participants into the Swanson and Ward (1995) conceptual framework of barriers to trial participation. For example, in response to requests related to sociocultural barriers, the case managers assisted participants in making medical appointments (i.e., interfacing with health systems) and provided information pertaining to African American community events. In response to requests related to economic barriers, the case managers helped participants obtain health insurance information, legal aid, transportation services, food programs, financial support, medication assistance, and free medical care. For requests related to individual barriers, the case managers helped the participants obtain information related to health risks facing African Americans, such as heart disease and diabetes. Finally, requests related to barriers inherent in study design included the provision of PLCO Cancer Screening Trial screening information and the scheduling of annual screening appointments.
Measures
Participants self-reported data pertaining to age at randomization, education, income, marital status, and work status. Researchers had collected these data at the time of enrollment in the PLCO Cancer Screening Trial.
We used geographic information system methods in order to obtain data pertaining to the income of each participant. Using census block group methods, we geocoded the home addresses of the 703 study participants. We then used census data in order to assign each study participant the average household income in the block-group of his residence (a block-group is a subdivision of a census tract roughly representing a city block; Pablos-Mendez, Knirsch, Barr, Lerner, & Frieden, 1997). We defined low income as an annual household income less than 1.5 times the poverty level, adjusted for household size, and moderate-to-high income as an annual household income greater than or equal to 1.5 times the poverty level, adjusted for household size. For example, if household size was 4, the average household income per person had to be greater than or equal to $19,050 to be considered moderate to high. We based the poverty index levels on Federal Register data for 1996, which corresponded with the 1990 Census data available for the geocoding procedure.
We defined adherence as completing the next scheduled PLCO Cancer Screening Trial screening. Prostate cancer screening was conducted via two methods: blood draw for the prostate-specific antigen (PSA) test and the digital rectal examination (DRE). Participants underwent PSA and DRE testing at baseline (time of randomization) and annually for 3 additional years. Researchers then administered the PSA test alone for an additional 2 years.
Lung cancer screening was conducted via chest x-ray. Researchers modified the chest x-ray exam schedule in December 1998 based on participants' smoking status. They defined an "ever smoker" as anyone who had ever smoked cigarettes for six months or longer in his or her lifetime or who had ever smoked pipes or cigars. Ever smokers in the PLCO Cancer Screening Trial screening arm received chest x-rays at baseline, Year 1, Year 2, and Year 3. Never smokers did not receive a Year 3 chest x-ray.
Colorectal cancer screening used flexible sigmoidoscopy (FSG) at baseline and Year 3 in the original study plan. In December 1998, researchers initiated a protocol change. The revised protocol for colorectal screening consisted of FSG at baseline and Year 5.
Analytic Approach
We defined adherence as completing the next scheduled PLCO Cancer Screening Trial screening. We included in the analyses only screening data obtained after the adherence trial began. We compared the distributions of education, income, marital status, and work status for participants in the intervention and control groups by using chi-square tests. We used Student's t test in order to compare mean age at randomization between the two groups.
We had hypothesized that income (low compared with moderate to high) would be an important effect modifier in screening adherence rates. Therefore, we accounted for the potential modifying effect of income in the power/sample size calculations. We used logistic regression modeling in order to test for an interaction between income and study group (i.e., case management or control) for each of the four screening tests (PSA test, chest x-ray, DRE, and FSG). We considered each of the four screening tests as an a priori and separate hypothesis. By using a hierarchical model approach, we included an interaction term between income and study group in each of the four separate models. We stratified the analyses by income group, and we compared the screening adherence rates between the intervention group and control group by using chi-square tests within income strata. We determined that all overall comparisons were significant at p <.05, and we considered all within-income-level comparisons to be significant at p <.025.
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Discussion |
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However, the inverse relationship between the number of calls received and adherence to FSG was unexpected. FSG was the most invasive type of screening used in the trial. It is possible that more intensive, face-to-face contact is required in order to enhance FSG adherence among study participants.
Study Limitations
Standardization of the delivery of a case management intervention in terms of offering and delivering the same services to each study participant is not feasible or desirable. By design, case management is an individualized approach based on the specific needs of a client. Thus, client needs—and types of services offered and delivered—varied. However, the observations that the number of intervention calls did not differ by income group but that the number of services requested and received was greater in the low-income group are consistent with the view that addressing competing needs of the low-income participants made them more likely to participate in the PLCO Cancer Screening Trial screenings.
The case management intervention employed a telephone-based design, and study participants were older African American men living in a metropolitan area who were asked to participate in a clinical trial to evaluate the effectiveness of cancer screening tests. The findings need to be replicated before they can be generalized to clinical trials of other cancer-related outcomes, such as treatment. Because the study population was restricted to older African American men, we do not know whether a case management intervention would be equally effective among low-income men of other racial ethnic groups or among younger African American men.
Implications of the Findings for Practice
Despite some limitations, this randomized trial has two major strengths that warrant its replication by investigators in future studies. First, it focused on older African American men, who as a group are more likely than others to be affected by prostate, lung, and colorectal cancer. Investigators with access to similar populations might find similar results. Second, because the Detroit metropolitan area is sociodemographically representative of other large, urban areas, it is likely that our study results could be used to enhance screening adherence among participants with low income at other PLCO Cancer Screening Trial study sites and, perhaps, in other clinical trials of screening tests for other diseases.
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Footnotes |
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1 Department of Biostatistics, Bioinformatics, and Epidemiology, Medical University of South Carolina, Charleston.
2 Department of Biostatistics and Research Epidemiology, Henry Ford Health Sciences Center, Detroit, MI.
3 Division of Health Promotion and Behavioral Sciences, School of Public Health, University of Texas Health Sciences Center, Houston.
4 Department of Medicine and Section of Health Services Research, Baylor College of Medicine Veterans Affairs Medical Center, Houston, TX.
5 Josephine Ford Cancer Center, Henry Ford Health Sciences Center, Detroit, MI.
6 Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson.
Decision Editor: Nancy Morrow-Howell, PhD,
Received for publication June 30, 2005. Accepted for publication December 22, 2005.
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