title: Socioeconomic factors and effect of evidence-based patient information about primary prevention of type 2 diabetes mellitus--are there interactions?
abstract: BACKGROUND
  Having shown in a recent randomized controlled trial that evidence-based patient information (EBPI) significantly increased knowledge on primary prevention of diabetes compared to standard patient information, we now investigated interaction between socioeconomic status (SES) and the effect of an EBPI.
  
  
  RESULTS
  1,120 visitors (aged 40-70 years, without known diabetes) to the "Techniker Krankenkasse" and the "German Diabetes Center" websites were randomized. The intervention group received a newly developed on-line EBPI, the control group standard on-line information. The primary outcome measure was knowledge, classified as "good/average/poor". We analyzed associations of knowledge with socioeconomic variables (education, vocational training, employment, subjective social status) combined with intervention effect including interactions, adjusted for possible confounding by knowledge before intervention, self-reported blood glucose measurements, blood pressure, blood lipid levels, age and gender. Logistic regression models were fitted to the subpopulation (n = 647) with complete values in these variables.Education (high vs. low) was significantly associated with knowledge (good vs. average/poor); however, there was no significant interaction between education and intervention. After adjustment, the other socioeconomic variables were not significantly associated with knowledge.
  
  
  CONCLUSIONS
  Socioeconomic variables did not significantly change the effect of the intervention. There was a tendency towards a lower effect where lower educated individuals were concerned. Possibly the power was too low to detect interaction effects. Larger studies using SES-specific designs are needed to clarify the effect of SES. We suggest considering the socioeconomic status when evaluating a decision aid, e.g. an EBPI, to ensure its effectiveness not only in higher socioeconomic groups.
  
  
  BACKGROUND
  Current Controlled Trials ISRCTN22060616 (Date assigned: 12 September 2008).
authors.affiliation: Institute of Biometrics and Epidemiology, German Diabetes Center, Leibniz Institute at the Heinrich Heine University Düsseldorf, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany. Jutta.Genz@ddz.uni-duesseldorf.de.
authors.forename: Jutta
authors.initials: J
authors.lastname: Genz
authors.forename: Burkhard
authors.initials: B
authors.lastname: Haastert
authors.forename: Hardy
authors.initials: H
authors.lastname: Müller
authors.forename: Frank
authors.initials: F
authors.lastname: Verheyen
authors.forename: Dennis
authors.initials: D
authors.lastname: Cole
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rathmann
authors.forename: Bettina
authors.initials: B
authors.lastname: Nowotny
authors.forename: Michael
authors.initials: M
authors.lastname: Roden
authors.forename: Guido
authors.initials: G
authors.lastname: Giani
authors.forename: Christian
authors.initials: C
authors.lastname: Ohmann
authors.forename: Andrea
authors.initials: A
authors.lastname: Icks
mesh_terms: D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000517:prevention & control*; D055317:Evidence-Based Practice; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011322:Primary Prevention; D012959:Socioeconomic Factors