title: Reducing lost to follow-up in a large clinical trial of prevention of mother-to-child transmission of HIV: the Breastfeeding, Antiretrovirals and Nutrition study experience.
abstract: OBJECTIVE
  Retaining patients in prevention of mother-to-child transmission of HIV studies can be challenging in resource-limited settings, where high lost to follow-up rates have been reported. In this article, we describe the effectiveness of methods used to encourage retention in the Breastfeeding, Antiretrovirals, and Nutrition study and analyze factors associated with lost to follow-up in the study.
  
  
  METHODS
  The Breastfeeding, Antiretrovirals, and Nutrition clinical trial was designed to evaluate the efficacy of three different mother-to-child HIV transmission prevention strategies. Lower than expected participant retention prompted enhanced efforts to reduce lost to follow-up during the conduct of the trial. Following study completion, we employed regression modeling to determine predictors of perfect attendance and variables associated with being lost to follow-up.
  
  
  RESULTS
  During the study, intensive tracing efforts were initiated after the first 1686 mother-infant pairs had been enrolled, and 327 pairs were missing. Of these pairs, 60 were located and had complete data obtained. Among the 683 participants enrolling after initiation of intensive tracing efforts, the lost to follow-up rate was 3.4%. At study's end, 290 (12.2%) of the 2369 mother-infant pairs were lost to follow-up. Among successfully traced missing pairs, relocation was common and three were deceased. Log-binomial regression modeling revealed higher maternal hemoglobin and older maternal age to be significant predictors of perfect attendance. These factors and the presence of food insecurity were also significantly associated with lower rates of lost to follow-up.
  
  
  CONCLUSIONS
  In this large HIV prevention trial, intensive tracing efforts centered on reaching study participants at their homes succeeded in finding a substantial proportion of lost to follow-up participants and were very effective in preventing further lost to follow-up during the remainder of the trial. The association between food insecurity and lower rates of lost to follow-up is likely related to the study's provision of nutritional support, including a family maize supplement, which may have contributed to patient retention.
authors.affiliation: Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Sellers
authors.affiliation: Department of Biostatistics, School of Public Health, Brown University, Providence, RI, USA.
authors.forename: Hana
authors.initials: H
authors.lastname: Lee
authors.affiliation: UNC Project, Lilongwe, Malawi Division of Epidemiology and Biostatistics, Faculty of Health Sciences, School of Public Health, University of Witwatersrand, Johannesburg, South Africa.
authors.forename: Charles
authors.initials: C
authors.lastname: Chasela
authors.affiliation: UNC Project, Lilongwe, Malawi.
authors.forename: Dumbani
authors.initials: D
authors.lastname: Kayira
authors.affiliation: UNC Project, Lilongwe, Malawi.
authors.forename: Alice
authors.initials: A
authors.lastname: Soko
authors.affiliation: UNC Project, Lilongwe, Malawi.
authors.forename: Innocent
authors.initials: I
authors.lastname: Mofolo
authors.affiliation: Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Sascha
authors.initials: S
authors.lastname: Ellington
authors.affiliation: Department of Biostatistics, School of Public Health, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hudgens
authors.affiliation: Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Athena P
authors.initials: AP
authors.lastname: Kourtis
authors.affiliation: Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Caroline C
authors.initials: CC
authors.lastname: King
authors.affiliation: Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Jamieson
authors.affiliation: Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, USA cvdh@med.unc.edu.
authors.forename: Charles
authors.initials: C
authors.lastname: van der Horst
mesh_terms: D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001942:Breast Feeding; D002675:Child, Preschool; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000517:prevention & control* / Q000635:transmission; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D059012:Lost to Follow-Up; D009035:Mothers; D011247:Pregnancy; D012107:Research Design; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents
keywords: Antiretroviral therapy; human immunodeficiency virus; lost to follow-up; prevention of mother-to-child transmission; retention; tracing