title: Sexual Partnership Patterns Among South African Adolescent Girls Enrolled in HPTN [corrected] 068: Measurement Challenges and Implications for HIV/STI Transmission.
abstract: BACKGROUND
  Estimates of sexual partnership durations, gaps between partnerships, and overlaps across partnerships are important for understanding sexual partnership patterns and developing interventions to prevent transmission of HIV/sexually transmitted infections (STIs). However, a validated, optimal approach for estimating these parameters, particularly when partnerships are ongoing, has not been established.
  
  
  METHODS
  We assessed 4 approaches for estimating partnership parameters using cross-sectional reports on dates of first and most recent sex and partnership status (ongoing or not) from 654 adolescent girls in rural South Africa. The first, commonly used, approach assumes all partnerships have ended, resulting in underestimated durations for ongoing partnerships. The second approach treats reportedly ongoing partnerships as right-censored, resulting in bias if partnership status is reported with error. We propose 2 "hybrid" approaches, which assign partnership status to reportedly ongoing partnerships based on how recently girls last had sex with their partner. We estimate partnership duration, gap length, and overlap length under each approach using Kaplan-Meier methods with a robust variance estimator.
  
  
  RESULTS
  Median partnership duration and overlap length varied considerably across approaches (from 368 to 1024 days and 168 to 409 days, respectively), but gap length was stable. Lifetime prevalence of concurrency ranged from 28% to 33%, and at least half of gap lengths were shorter than 6 months, suggesting considerable potential for HIV/STI transmission.
  
  
  CONCLUSIONS
  Estimates of partnership duration and overlap lengths are highly dependent on measurement approach. Understanding the effect of different approaches on estimates is critical for interpreting partnership data and using estimates to predict HIV/STI transmission rates.
authors.affiliation: From the *Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC; †Department of Biostatistics, University of Washington, Seattle, WA; ‡University of New England, Armidale, New South Wales, Australia; §Department of Pathology, Johns Hopkins University, Baltimore, MD; ¶National Institutes of Health, Bethesda, MD; and ∥MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Witwatersrand, South Africa.
authors.forename: Nadia L
authors.initials: NL
authors.lastname: Nguyen
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Powers
authors.forename: James P
authors.initials: JP
authors.lastname: Hughes
authors.forename: Catherine L
authors.initials: CL
authors.lastname: MacPhail
authors.forename: Estelle
authors.initials: E
authors.lastname: Piwowar-Manning
authors.forename: Eshan U
authors.initials: EU
authors.lastname: Patel
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Gomez-Olive
authors.forename: Kathleen
authors.initials: K
authors.lastname: Kahn
authors.forename: Audrey E
authors.initials: AE
authors.lastname: Pettifor
mesh_terms: D000293:Adolescent; D044383:Black People; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015995:Prevalence; D012309:Risk-Taking; D012424:Rural Population; D012725:Sexual Behavior / Q000523:psychology* / Q000706:statistics & numerical data; D012747:Sexual Partners / Q000523:psychology*; D012749:Sexually Transmitted Diseases / Q000517:prevention & control* / Q000523:psychology / Q000635:transmission; D013019:South Africa / Q000453:epidemiology; D013997:Time Factors