title: Implementation and Operational Research: CD4 Count Monitoring Frequency and Risk of CD4 Count Dropping Below 200 Cells Per Cubic Millimeter Among Stable HIV-Infected Patients in New York City, 2007-2013.
abstract: BACKGROUND
  The evidence has begun to mount for diminishing the frequency of CD4 count testing. To determine whether these observations were applicable to an urban US population, we used New York City (NYC) surveillance data to explore CD4 testing among stable patients in NYC, 2007-2013.
  
  
  METHODS
  We constructed a population-based retrospective open cohort analysis of NYC HIV surveillance data. HIV+ patients aged ≥ 13 years with stable viral suppression (≥ 1 viral load the previous year; all <400 copies per milliliter) and immune status (≥ 1 CD4 the previous year; all ≥ 200 cells per cubic millimeter) entered the cohort the following year beginning January 1, 2007. Each subsequent year, eligible patients not previously included entered the cohort on January 1. Outcomes were annual frequency of CD4 monitoring and probability of maintaining CD4 ≥ 200 cells per cubic millimeter. A multivariable Cox model identified factors associated with maintaining CD4 ≥ 200 cells per cubic millimeter.
  
  
  RESULTS
  During 1.9 years of observation (median), 62,039 patients entered the cohort. The mean annual number of CD4 measurements among stable patients was 2.8 and varied little by year or characteristic. Two years after entering, 93.4% and 97.8% of those with initial CD4 350-499 and CD4 ≥ 500 cells per cubic millimeter, respectively, maintained CD4 ≥ 200 cells per cubic millimeter. Compared to those with initial CD4 ≥ 500 cells per cubic millimeter, those with CD4 200-349 cells per cubic millimeter and CD4 350-499 cells per cubic millimeter were more likely to have a CD4 <200 cells per cubic millimeter, controlling for sex, race, age, HIV risk group, and diagnosis year.
  
  
  CONCLUSIONS
  In a population-based US cohort with well-controlled HIV, the probability of maintaining CD4 ≥ 200 cells per cubic millimeter for ≥ 2 years was >90% among those with initial CD4 ≥ 350 cells per cubic millimeter, suggesting that limited CD4 monitoring in these patients is appropriate.
authors.affiliation: *Bureau of HIV/AIDS Prevention and Control, Division of Disease Control, New York City Department of Health and Mental Hygiene, Queens, NY;†Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY; and‡Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY.
authors.forename: Julie E
authors.initials: JE
authors.lastname: Myers
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xia
authors.forename: Lucia V
authors.initials: LV
authors.lastname: Torian
authors.forename: Mary
authors.initials: M
authors.lastname: Irvine
authors.forename: Graham
authors.initials: G
authors.lastname: Harriman
authors.forename: Kent A
authors.initials: KA
authors.lastname: Sepkowitz
authors.forename: Colin W
authors.initials: CW
authors.lastname: Shepard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018791:CD4 Lymphocyte Count / Q000379:methods / Q000592:standards; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009519:New York City / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult