title: Clinic variation in recruitment metrics, patient characteristics and treatment use in a randomized clinical trial of osteoarthritis management.
abstract: BACKGROUND
  The Patient and PRovider Interventions for Managing Osteoarthritis (OA) in Primary Care (PRIMO) study is one of the first health services trials targeting OA in a multi-site, primary care network. This multi-site approach is important for assessing generalizability of the interventions. These analyses describe heterogeneity in clinic and patient characteristics, as well as recruitment metrics, across PRIMO study clinics.
  
  
  METHODS
  Baseline data were obtained from the PRIMO study, which enrolled n = 537 patients from ten Duke Primary Care practices. The following items were examined across clinics with descriptive statistics: (1) Practice Characteristics, including primary care specialty, numbers and specialties of providers, numbers of patients age 55+, urban/rural location and county poverty level; (2) Recruitment Metrics, including rates of eligibility, refusal and randomization; (3) Participants' Characteristics, including demographic and clinical data (general and OA-related); and (4) Participants' Self-Reported OA Treatment Use, including pharmacological and non-pharmacological therapies. Intraclass correlation coefficients (ICCs) were computed for participant characteristics and OA treatment use to describe between-clinic variation.
  
  
  RESULTS
  Study clinics varied considerably across all measures, with notable differences in numbers of patients age 55+ (1,507-5,400), urban/rural location (ranging from "rural" to "small city"), and proportion of county households below poverty level (12%-26%). Among all medical records reviewed, 19% of patients were initially eligible (10%-31% across clinics), and among these, 17% were randomized into the study (13%-21% across clinics). There was considerable between-clinic variation, as measured by the ICC (>0.01), for the following patient characteristics and OA treatment use variables: age (means: 60.4-66.1 years), gender (66%-88% female), race (16%-61% non-white), low income status (5%-27%), presence of hip OA (26%-68%), presence both knee and hip OA (23%-61%), physical therapy for knee OA (24%-61%) and hip OA (0%-71%), and use of knee brace with metal supports (0%-18%).
  
  
  CONCLUSIONS
  Although PRIMO study sites were part of one primary care practice network in one health care system, clinic and patient characteristics varied considerably, as did OA treatment use. This heterogeneity illustrates the importance of including multiple, diverse sites in trials for knee and hip OA, to enhance the generalizability and evaluate potential for real-world implementation.
  
  
  BACKGROUND
  
  
  
  BACKGROUND
  NCT 01435109.
authors.affiliation: Health Services Research and Development Service, Durham VA Medical Center, Durham, NC, USA. kdallen@email.unc.edu.
authors.forename: Kelli D
authors.initials: KD
authors.lastname: Allen
authors.forename: Hayden B
authors.initials: HB
authors.lastname: Bosworth
authors.forename: Ranee
authors.initials: R
authors.lastname: Chatterjee
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Coffman
authors.forename: Leonor
authors.initials: L
authors.lastname: Corsino
authors.forename: Amy S
authors.initials: AS
authors.lastname: Jeffreys
authors.forename: Eugene Z
authors.initials: EZ
authors.lastname: Oddone
authors.forename: Catherine
authors.initials: C
authors.lastname: Stanwyck
authors.forename: William S
authors.initials: WS
authors.lastname: Yancy
authors.forename: Rowena J
authors.initials: RJ
authors.lastname: Dolor
mesh_terms: D000368:Aged; D019468:Disease Management; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D018579:Patient Selection; D011320:Primary Health Care / Q000379:methods; D012959:Socioeconomic Factors; D016896:Treatment Outcome