title: Patient characteristics and participation in a genetic study: a type 2 diabetes cohort.
abstract: BACKGROUND
  Recruitment of large, diverse populations into genetic studies remains challenging. Potential strategies to overcome limitations include leveraging electronic health data and minimizing patient burden. We sought to describe the overall participation rate and identify characteristics associated with participation in a genetic substudy of patients with type 2 diabetes mellitus, in which patients were identified via electronic hospital data and asked to participate by providing DNA samples by mail.
  
  
  METHODS
  During a phone interview, participants (n = 455) were asked to take part in a genetic substudy. Subjects verbally consenting were mailed saliva collection kits and written consent forms. We examined demographic and clinical variables associated with verbal consent and DNA kit return using logistic regression.
  
  
  RESULTS
  Overall, 90% (n = 410) verbally consented to the genetic substudy during interviews. However, of those consenting, only 70% returned the DNA kit (n = 287). Among those consenting, after covariate adjustment, male sex (odds ratio [OR], 1.70; 95% confidence interval [CI], 1.09-2.65), African American race (OR, 0.61; 95% CI, 0.39-0.95), hemoglobin A1c (HbA1c) (OR, 0.87; 95% CI, 0.75-1.00), and physical activity (OR, 0.58; 95% CI, 0.37-0.91) were significantly associated with DNA kit return.
  
  
  CONCLUSIONS
  To our knowledge, we are the first to demonstrate an inverse association between HbA1c and participation in genetic research, potentially indicating a compliance-related trait needing further exploration. The DNA kit return rate being notably lower than the verbal consent rate suggests that the greater convenience of a telephone/mail-in process did not drastically enhance full participation. Direct comparison to in-person donation may be warranted.
authors.affiliation: From the *Endocrinology, Diabetes, Bone and Mineral Disorders, Henry Ford Health System; and †Department of Public Health Sciences, Henry Ford Hospital, Detroit, MI; ‡EpiSource, Newton, MA; and §Heart and Vascular Institute and Center for Health Services and Policy Research, Henry Ford Health System, Detroit, MI.
authors.forename: Loabat
authors.initials: L
authors.lastname: Amiri
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Cassidy-Bushrow
authors.forename: Heather
authors.initials: H
authors.lastname: Dakki
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Karen
authors.initials: K
authors.lastname: Wells
authors.forename: Susan A
authors.initials: SA
authors.lastname: Oliveria
authors.forename: Marianne Ulcickas
authors.initials: MU
authors.lastname: Yood
authors.forename: Abraham
authors.initials: A
authors.lastname: Thomas
authors.forename: David E
authors.initials: DE
authors.lastname: Lanfear
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis* / Q000235:genetics* / Q000523:psychology; D005260:Female; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D010358:Patient Participation / Q000523:psychology