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Surveys of Undiagnosed STIs Bias due to Missing Biospecimens. Charles Turner & Susan Rogers for MSPP Research Team. Disclosures. Neither author has personal financial relationships with commercial interests relevant to this presentation
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Surveys of Undiagnosed STIsBias due to Missing Biospecimens Charles Turner & Susan Rogers for MSPP Research Team
Disclosures Neither author has personal financial relationships with commercial interests relevant to this presentation Dr. Rogers is employed by and Dr. Turner is a consultant to the Research Triangle Institute (RTI). RTI is a non-profit research organization that conducts surveys and other research for federal, state, and commercial clients.
Research Support NIH grant R01-HD047163 from the National Institute of Child Health and Human Development
Monitoring STIs in the PopulationResearch Team Susan Rogers, PI, Research Triangle Institute Charles Turner, Co-PI, CUNY Bill Miller, UNC School of Medicine Emily Erbelding, JHU School of Medicine Marcia Hobbs, UNC School of Medicine Elizabeth Eggleston, Research Triangle Institute Anthony Roman, University of Massachusetts Sylvia Tan, Research Triangle Institute James Chromy, Research Triangle Institute
Monitoring Undiagnosed STIs in Populations A New Paradigm for STI Epidemiology Focus simultaneously on • diagnosed infections reported to DoH • undiagnosed infections prevalent in population
1998 Baltimore STD and Behavior Survey • In-person survey with biospecimens; Adults 18-35 • 79% biospecimen acceptance • 7.9% prevalence of undiagnosed GC and/or CT; 15% among black females Source: Turner, Rogers et al., JAMA, Feb. 13, 2002
1998 Baltimore STD and Behavior Survey • More Undiagnosed Infections than Annual Diagnosed Infections reported to DOH
MSPP Survey Program, 2006-2009 • Adolescents and Adults in Baltimore • Ages 15 to 35 • Full probability sample • Fall 2006 thru Summer 2009
Survey Execution • 73,318 Telephone Numbers dialed • 20,435 Households Identified • 14,199 Households Screened • 4,998 Eligible Respondents Identified • 2,936 (59%) of Eligibles Interviewed
Measurements • T-ACASI interviews on sexual behaviors and STI history • Biospecimens: Urine and Vaginal Swabs • NAAT testing for Chlamydia, Gonorrhea, and Trichomonas
Biospecimens • Biospecimens requested from All Survey Respondents • Mail-out and Mail-Back kits via US Postal Service • Monetary Incentive, $40 to $100 • NAAT assays for Ct, GC, Tv
Biospecimen Acceptance • 2,936 did 13-Minute Survey Interview • 2,522 (86%) agreed to biospecimen • 2,120 (72%) biospecimens received
Biospecimen NonResponse • 414 completed interview but refused request for biospecimen • 402 agreed but did not supply biospecimen despite repeated requests
Performance Improved with Experience% supplying biospecimens(linear p < 0.05)
Equivalent Acceptance by Gender, Race, Marital Status% supplying biospecimens(all p > 0.40)
Varied Slightly for Hispanics and by Education(HISP: p = 0.08; EDUC p = 0.02)
Modest Variation by Number of Sex Partners in Past Year(Categorical: p = 0.09; Linear p > 0.50) Number of Partners, 12 mo.
Equivalent Testing for Respondents with Same-Gender Sex History (Male: p > 0.50; Female: p > 0.50) Ever Had Same-Gender Sex
More Likely to Test when “Don’t Know” if Partner diagnosed with STI in past Year(p = 0.03) Partner Diagnosed with STI, 12 mo.
Less Likely to Test if had a New Partner in Past Month !! (p = 0.01, last month vs. longer) New Partner Recency
More Likely to Test if Ever Had Trichomonas but not GC or CT p = 0.37 (GC), 0.57 (CT), 0.02 (TV) Any Lifetime Infection
Less Likely to Test if Had GC in Past Year p = 0.01 (GC), > 0.50 (CT), 0.35 (TV) Infection in Last Year
Impact of Missing Biospecimens Joint Impact of: • Difference in characteristics of persons who do and do not provide biospecimens; and • Association of infection likelihood with those characteristics
Synthetic Estimates • 2,120 biospecimens • 787 imputations with full socio-demographics, sexual behaviors, STD history, and symptoms • 16 imputations from socio-demographics & reduced sex and STI indicators • 13 cases imputed from socio-demographics only
Estimate of Undiagnosed Trichomonas vaginalis • From Biospecimens 7.6% • Biospecimens plus Imputations 7.3%
Estimate of Undiagnosed Chlamydia and/or Trichomonas • From Biospecimens 10.6% • Biospecimens plus Imputations 10.2%
CONCLUSION • Feasible • Important • New Paradigm for STI Epidemiology