title: The HIV Care Continuum: Changes over Time in Retention in Care and Viral Suppression.
abstract: BACKGROUND
  The HIV care continuum (diagnosis, linkage to care, retention in care, receipt of antiretroviral therapy (ART), viral suppression) has been used to identify opportunities for improving the delivery of HIV care. Continuum steps are typically calculated in a conditional manner, with the number of persons completing the prior step serving as the base population for the next step. This approach may underestimate the prevalence of viral suppression by excluding patients who are suppressed but do not meet standard definitions of retention in care. Understanding how retention in care and viral suppression interact and change over time may improve our ability to intervene on these steps in the continuum.
  
  
  METHODS
  We followed 17,140 patients at 11 U.S. HIV clinics between 2010-2012. For each calendar year, patients were classified into one of five categories: (1) retained/suppressed, (2) retained/not-suppressed, (3) not-retained/suppressed, (4) not-retained/not-suppressed, and (5) lost to follow-up (for calendar years 2011 and 2012 only). Retained individuals were those completing ≥ 2 HIV medical visits separated by ≥ 90 days in the year. Persons not retained completed ≥ 1 HIV medical visit during the year, but did not meet the retention definition. Persons lost to follow-up had no HIV medical visits in the year. HIV viral suppression was defined as HIV-1 RNA ≤ 200 copies/mL at the last measure in the year. Multinomial logistic regression was used to determine the probability of patients' transitioning between retention/suppression categories from 2010 to 2011 and 2010 to 2012, adjusting for age, sex, race/ethnicity, HIV risk factor, insurance status, CD4 count, and use of ART.
  
  
  RESULTS
  Overall, 65.8% of patients were retained/suppressed, 17.4% retained/not-suppressed, 10.0% not-retained/suppressed, and 6.8% not-retained/not-suppressed in 2010. 59.5% of patients maintained the same status in 2011 (kappa=0.458) and 53.3% maintained the same status in 2012 (kappa=0.437).
  
  
  CONCLUSIONS
  Not counting patients not-retained/suppressed as virally suppressed, as is commonly done in the HIV care continuum, underestimated the proportion suppressed by 13%. Applying the care continuum in a longitudinal manner will enhance its utility.
authors.affiliation: Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America; Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA, United States of America; Center for Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America.
authors.forename: Baligh R
authors.initials: BR
authors.lastname: Yehia
authors.affiliation: Center for Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America.
authors.forename: Alisa J
authors.initials: AJ
authors.lastname: Stephens-Shields
authors.affiliation: Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality, Rockville, MD, United States of America.
authors.forename: John A
authors.initials: JA
authors.lastname: Fleishman
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Berry
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
authors.forename: Allison L
authors.initials: AL
authors.lastname: Agwu
authors.affiliation: General Medicine Division, Massachusetts General Hospital, Boston, MA, United States of America.
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Metlay
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Moore
authors.affiliation: Department of Medicine, University of California San Diego, San Diego, CA, United States of America.
authors.forename: W
authors.initials: W
authors.lastname: Christopher Mathews
authors.affiliation: Department of Medicine, University of Texas Southwestern, Dallas, TX, United States of America.
authors.forename: Ank
authors.initials: A
authors.lastname: Nijhawan
authors.affiliation: Division of General Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, United States of America.
authors.forename: Richard
authors.initials: R
authors.lastname: Rutstein
authors.affiliation: Department of Infectious Diseases, St. Jude's Children's Hospital, Memphis, TN, United States of America.
authors.forename: Aditya H
authors.initials: AH
authors.lastname: Gaur
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Gebo
mesh_terms: D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count; D003266:Continuity of Patient Care; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1; D006801:Humans; D019458:Insurance Coverage; D059012:Lost to Follow-Up; D008297:Male; D008875:Middle Aged; D014481:United States; D019562:Viral Load; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents