title: Retinal arterioles narrow with increasing duration of anti-retroviral therapy in HIV infection: a novel estimator of vascular risk in HIV?
abstract: OBJECTIVE
  HIV infection is associated with an increased risk of age-related morbidity mediated by immune dysfunction, atherosclerosis and inflammation. Changes in retinal vessel calibre may reflect cumulative structural damage arising from these mechanisms. The relationship of retinal vessel calibre with clinical and demographic characteristics was investigated in a population of HIV-infected individuals in South Africa.
  
  
  METHODS
  Case-control study of 491 adults ≥30 years, composed of 242 HIV-infected adults and 249 age- and gender-matched HIV-negative controls. Retinal vessel calibre was measured using computer-assisted techniques to determine mean arteriolar and venular diameters of each eye.
  
  
  RESULTS
  The median age was 40 years (IQR: 35-48 years). Among HIV-infected adults, 87.1% were receiving highly active antiretroviral therapy (HAART) (median duration, 58 months), their median CD4 count was 468 cells/µL, and 84.3% had undetectable plasma viral load. Unadjusted mean retinal arteriolar diameters were 163.67±17.69 µm in cases and 161.34±17.38 µm in controls (p = 0.15). Unadjusted mean venular diameters were 267.77±18.21 µm in cases and 270.81±18.98 µm in controls (p = 0.07). Age modified the effect of retinal arteriolar and venular diameters in relation to HIV status, with a tendency towards narrower retinal diameters in HIV cases but not in controls. Among cases, retinal arteriolar diameters narrowed with increasing duration of HAART, independently of age (167.83 µm <3 years of HAART vs. 158.89 µm >6 years, p-trend = 0.02), and with a HIV viral load >10,000 copies/mL while on HAART (p = 0.05). HIV-related venular changes were not detected.
  
  
  CONCLUSIONS
  Narrowing of retinal arteriolar diameters is associated with HAART duration and viral load, and may reflect heightened inflammatory and pro-atherogenic states of the systemic vasculature. Measurement of retinal vascular calibre could be an innovative non-invasive method of estimating vascular risk in HIV-infected individuals.
authors.affiliation: International Centre for Eye Health, Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom. sophia.pathai@lshtm.ac.uk
authors.forename: Sophia
authors.initials: S
authors.lastname: Pathai
authors.forename: Helen A
authors.initials: HA
authors.lastname: Weiss
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Lawn
authors.forename: Tunde
authors.initials: T
authors.lastname: Peto
authors.forename: Leris M
authors.initials: LM
authors.lastname: D'Costa
authors.forename: Colin
authors.initials: C
authors.lastname: Cook
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
authors.forename: Clare E
authors.initials: CE
authors.lastname: Gilbert
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D001160:Arterioles / Q000187:drug effects* / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012171:Retinal Vessels / Q000187:drug effects* / Q000473:pathology
chemical_list: D019380:Anti-HIV Agents