title: Study design, recruitment, and baseline characteristics: the Department of Veterans Affairs Dental Diabetes Study.
abstract: OBJECTIVE
  We are conducting a clinical trial of the efficacy of periodontal therapy in the improvement of glycaemic control in veterans with poorly controlled diabetes. This report describes study design, recruitment and randomization and compares baseline characteristics of the sample frame with those randomized into study groups.
  
  
  METHODS
  Veterans with poorly controlled diabetes were randomized in two groups: immediate periodontal therapy ("early treatment") or usual care followed by periodontal therapy ("deferred treatment"). Half of each group continued care for 12 months; the other half returned to their usual care. We studied baseline patient characteristics, self-reported health measures, and clinical examination data. We examined means for continuous variables, frequencies for categorical variables and compared groups using t-tests and chi(2) tests (alpha=0.05 for both).
  
  
  RESULTS
  The 193 randomized participants were younger (58 years) and had slightly higher HbA1c (10.2%) than the 2534 non-randomized participants (64 years, HbA1c =9.8%). The deferred treatment group was more likely than the early treatment group to have a history of stroke, transient ischaemic attacks, and less likely to be current or former smokers.
  
  
  CONCLUSIONS
  The mechanism for randomization was largely successful in this study.
authors.affiliation: VA Center for Health Quality, Outcomes and Economic Research, Bedford, MA 01730, USA. judjones@bu.edu
authors.forename: Judith A
authors.initials: JA
authors.lastname: Jones
authors.forename: Donald R
authors.initials: DR
authors.lastname: Miller
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Wehler
authors.forename: Sharron
authors.initials: S
authors.lastname: Rich
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Krall
authors.forename: Cindy L
authors.initials: CL
authors.lastname: Christiansen
authors.forename: James A
authors.initials: JA
authors.lastname: Rothendler
authors.forename: Raul I
authors.initials: RI
authors.lastname: Garcia
mesh_terms: D000367:Age Factors; D001786:Blood Glucose / Q000032:analysis; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D002546:Ischemic Attack, Transient / Q000150:complications; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D010510:Periodontal Diseases / Q000150:complications / Q000628:therapy*; D010514:Periodontal Pocket / Q000150:complications / Q000628:therapy; D012107:Research Design; D016037:Single-Blind Method; D012907:Smoking; D020521:Stroke / Q000150:complications
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin