title: Novel strategies implemented to ensure high participant retention rates in a community based HIV prevention effectiveness trial in South Africa and Zimbabwe.
abstract: BACKGROUND
  The identification of new HIV prevention methods that women can initiate themselves are urgently needed, particularly in high prevalence settings. HIV prevention trials must be designed with large sample sizes and/or substantial follow-up periods to ensure enough statistical power to measure product effectiveness. This paper describes the attendance rates of the Methods for Improving Reproductive Health in Africa (MIRA) trial, reasons for missed visits, and strategies used to retain participants; and examines demographic and behavioural predictors of retaining women.
  
  
  METHODS
  HIV negative, sexually active females were enrolled into the MIRA trial in Zimbabwe and South Africa. Once enrolled, women were expected to visit the clinic at 2 weeks and quarterly thereafter for 12 to 24 months. Tabulations of visit-specific retention rates are presented, along with a descriptive summary of retention strategies established prior to and in response to challenges incurred during implementation. Both univariate and multivariate logistic regression models were created in STATA to examine predictors of being retained vs. lost-to-follow-up.
  
  
  RESULTS
  At the three sites, the final retention rates were 94%, 93% and 89% for Zimbabwe, Durban and Johannesburg, respectively. This was achievable through intensive outreach efforts toward the latter part of the trial and a commitment from all staff. Each site implemented several retention strategies.
  
  
  CONCLUSIONS
  The high retention rates were achievable in this trial through added staff efforts and resources. Community involvement was also crucial to achieve these rates. Retention of trial participants should be considered during trial design and implemented from the onset.
authors.affiliation: HIV Prevention Research Unit, Medical Research Council, South Africa. sgappoo@mrc.ac.za
authors.forename: Sharika
authors.initials: S
authors.lastname: Gappoo
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Montgomery
authors.forename: Caitlin
authors.initials: C
authors.lastname: Gerdts
authors.forename: Sarita
authors.initials: S
authors.lastname: Naidoo
authors.forename: Agnes
authors.initials: A
authors.lastname: Chidanyika
authors.forename: Busi
authors.initials: B
authors.lastname: Nkala
authors.forename: Gita
authors.initials: G
authors.lastname: Ramjee
mesh_terms: D000328:Adult; D002986:Clinical Trials as Topic / Q000379:methods*; D003153:Community Health Services; D016001:Confidence Intervals; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control*; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D016015:Logistic Models; D009042:Motivation; D015999:Multivariate Analysis; D016017:Odds Ratio; D010358:Patient Participation; D015995:Prevalence; D013019:South Africa / Q000453:epidemiology; D011795:Surveys and Questionnaires; D015030:Zimbabwe / Q000453:epidemiology