title: Development and validation of the San Diego Early Test Score to predict acute and early HIV infection risk in men who have sex with men.
abstract: BACKGROUND
  Although men who have sex with men (MSM) represent a dominant risk group for human immunodeficiency virus (HIV), the risk of HIV infection within this population is not uniform. The objective of this study was to develop and validate a score to estimate incident HIV infection risk.
  
  
  METHODS
  Adult MSM who were tested for acute and early HIV (AEH) between 2008 and 2014 were retrospectively randomized 2:1 to a derivation and validation dataset, respectively. Using the derivation dataset, each predictor associated with an AEH outcome in the multivariate prediction model was assigned a point value that corresponded to its odds ratio. The score was validated on the validation dataset using C-statistics.
  
  
  RESULTS
  Data collected at a single HIV testing encounter from 8326 unique MSM were analyzed, including 200 with AEH (2.4%). Four risk behavior variables were significantly associated with an AEH diagnosis (ie, incident infection) in multivariable analysis and were used to derive the San Diego Early Test (SDET) score: condomless receptive anal intercourse (CRAI) with an HIV-positive MSM (3 points), the combination of CRAI plus ≥5 male partners (3 points), ≥10 male partners (2 points), and diagnosis of bacterial sexually transmitted infection (2 points)-all as reported for the prior 12 months. The C-statistic for this risk score was >0.7 in both data sets.
  
  
  CONCLUSIONS
  The SDET risk score may help to prioritize resources and target interventions, such as preexposure prophylaxis, to MSM at greatest risk of acquiring HIV infection. The SDET risk score is deployed as a freely available tool at http://sdet.ucsd.edu.
authors.affiliation: Division of Infectious Diseases, University of California, San Diego Section of Infectious Diseases and Tropical Medicine Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Hoenigl
authors.affiliation: Department of Computer Science and Engineering, University of California, San Diego.
authors.forename: Nadir
authors.initials: N
authors.lastname: Weibel
authors.affiliation: Division of Infectious Diseases, University of California, San Diego Veterans Affairs Healthcare System, San Diego, California.
authors.forename: Sanjay R
authors.initials: SR
authors.lastname: Mehta
authors.affiliation: Division of Infectious Diseases, University of California, San Diego.
authors.forename: Christy M
authors.initials: CM
authors.lastname: Anderson
authors.affiliation: Division of Infectious Diseases, University of California, San Diego.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Jenks
authors.affiliation: Division of Infectious Diseases, University of California, San Diego.
authors.forename: Nella
authors.initials: N
authors.lastname: Green
authors.affiliation: Division of Infectious Diseases, University of California, San Diego.
authors.forename: Sara
authors.initials: S
authors.lastname: Gianella
authors.affiliation: Division of Infectious Diseases, University of California, San Diego Veterans Affairs Healthcare System, San Diego, California.
authors.forename: Davey M
authors.initials: DM
authors.lastname: Smith
authors.affiliation: Division of Infectious Diseases, University of California, San Diego.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Little
mesh_terms: D000328:Adult; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D011897:Random Allocation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment
keywords: MSM; acute and early HIV; risk behavior; risk score