Objectives: Colorectal cancer (CRC) screening tests differ in benefits, harms, and processes, making individual informed decisions preference based. The objective was to analyze the preferences of insurees in Germany for characteristics of CRC screening modalities.
Methods: A generic discrete choice experiment with 2-alternative choice sets and 6 attributes (CRC mortality, CRC incidence, complications, preparation, need for transportation, and follow-up; 3 levels each) depicting characteristics of fecal testing, sigmoidoscopy, and colonoscopy was generated. Participants completed 8 choice tasks. Internal validity was tested using a within-set dominated pair. Between June and October 2020, written questionnaires were sent to a stratified random sample (n = 5000) of 50-, 55-, and 60-year-old insurees of the AOK (Allgemeine Ortskrankenkasse) Lower Saxony, who had previously received an invitation to participate in the organized screening program including evidence-based information. Preferences were analyzed using conditional logit, mixed logit, and latent-class model.
Results: From 1282 questionnaires received (26% [1282 of 4945]), 1142 were included in the analysis. Approximately 42% of the respondents chose the dominated alternative in the internal validity test. Three heterogeneous preference classes were identified. Most important attributes were preparation (class 1; n = 505, 44%), CRC mortality (class 2; n = 347, 30%), and CRC incidence (class 3; n = 290, 25%). Contrary to a priori expectations, a higher effort was preferred for bowel cleansing (class 1) and accompaniment home (classes 1 and 2).
Conclusion: Internal validity issues of choice data need further research and warrant attention in future discrete choice experiment surveys. The observed preference heterogeneity suggests different informational needs, although the underlying reasons remained unclear.
Keywords: colorectal cancer screening; discrete choice experiment; latent-class model; preference heterogeneity; validity testing.
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