title: A New Method for Estimating the Number of Undiagnosed HIV Infected Based on HIV Testing History, with an Application to Men Who Have Sex with Men in Seattle/King County, WA.
abstract: We develop a new approach for estimating the undiagnosed fraction of HIV cases, the first step in the HIV Care Cascade. The goal is to address a critical blindspot in HIV prevention and treatment planning, with an approach that simplifies data requirements and can be implemented with open-source software. The primary data required is HIV testing history information on newly diagnosed cases. Two methods are presented and compared. The first is a general methodology based on simplified back-calculation that can be used to assess changes in the undiagnosed fraction over time. The second makes an assumption of constant incidence, allowing the estimate to be expressed as a simple closed formula calculation. We demonstrate the methods with an application to HIV diagnoses among men who have sex with men (MSM) from Seattle/King County. The estimates suggest that 6% of HIV-infected MSM in King County are undiagnosed, about one-third of the comparable national estimate. A sensitivity analysis on the key distributional assumption gives an upper bound of 11%. The undiagnosed fraction varies by race/ethnicity, with estimates of 4.9% among white, 8.6% of African American, and 9.3% of Hispanic HIV-infected MSM being undiagnosed.
authors.affiliation: Fellows Statistics, San Diego, CA, United States of America.
authors.forename: Ian E
authors.initials: IE
authors.lastname: Fellows
authors.affiliation: Department of Sociology, University of Washington, Seattle, WA, United States of America; Department of Statistics, University of Washington, Seattle, WA, United States of America.
authors.forename: Martina
authors.initials: M
authors.lastname: Morris
authors.affiliation: Center for AIDS Research, University of Washington, Seattle, WA, United States of America.
authors.forename: Jeanette K
authors.initials: JK
authors.lastname: Birnbaum
authors.affiliation: Division of Allergy & Infectious Diseases, University of Washington School of Medicine, Seattle, WA, United States of America.
authors.forename: Julia C
authors.initials: JC
authors.lastname: Dombrowski
authors.affiliation: Department of Epidemiology, University of Washington School of Public Health, Seattle, WA, United States of America; HIV/AIDS Program, Public Health Seattle/King County, Seattle, WA, United States of America.
authors.forename: Susan
authors.initials: S
authors.lastname: Buskin
authors.affiliation: Department of Epidemiology, University of Washington School of Public Health, Seattle, WA, United States of America.
authors.forename: Amy
authors.initials: A
authors.lastname: Bennett
authors.affiliation: Division of Allergy & Infectious Diseases, University of Washington School of Medicine, Seattle, WA, United States of America; HIV/AIDS Program, Public Health Seattle/King County, Seattle, WA, United States of America.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Golden
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data; D015658:HIV Infections / Q000453:epidemiology* / Q000208:ethnology; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D018451:Homosexuality, Male / Q000208:ethnology / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008403:Mass Screening; D015233:Models, Statistical; D014861:Washington / Q000453:epidemiology / Q000208:ethnology; D044465:White People / Q000706:statistics & numerical data