title: Platelet decline as a predictor of brain injury in HIV infection.
abstract: An association between platelet decline and increased risk of progression to dementia has been observed in an advanced HIV infection cohort study. This investigation evaluated the prognostic significance of platelet decline for dementia, for psychomotor slowing, and for brain injury, as quantified in vivo, in a much larger population of HIV+ men. Platelet counts and neurocognitive data were available from biannual visits of 2,125 HIV+ men participating in the prospective, Multicenter AIDS Cohort Study from 1984 to 2009. Brain volumetric data were also available from an imaging substudy of 83 seropositive participants aged 50 and older. The association of platelet counts with neurocognitive outcome was assessed using Cox proportional hazard models where change in platelet count from baseline was a time-updated variable. Marked platelet decline was associated with increased risk of dementia in univariate analysis (hazard ratio [HR] = 2.5, 95% confidence interval [CI] = 1.8-3.5), but not after adjustment for CD4 cell count, HIV viral load, age, study site, hemoglobin, race, education, smoking, and alcohol use (HR = 1.4, 95% CI = 0.78-2.5). Platelet decline did not predict psychomotor slowing in either univariate (HR = 0.79, 95% CI = 0.58-1.08) or multivariate (HR = 1.10, 95% CI = 0.73-1.67) analysis. Analysis of brain volumetric data, however, indicated a relationship between platelet decline and reduced gray matter volume fraction in univariate (p = 0.06) and multivariate (p < 0.05) analyses. Platelet decline was not an independent predictor of dementia or psychomotor slowing, after adjusting for stage of disease. Findings from a structural brain imaging substudy of older participants, however, support a possible relationship between platelet decline and reduced gray matter.
authors.affiliation: Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. ann-ragin@northwestern.edu
authors.forename: Ann B
authors.initials: AB
authors.lastname: Ragin
authors.forename: Gypsyamber
authors.initials: G
authors.lastname: D'Souza
authors.forename: Sandra
authors.initials: S
authors.lastname: Reynolds
authors.forename: Eric
authors.initials: E
authors.lastname: Miller
authors.forename: Ned
authors.initials: N
authors.lastname: Sacktor
authors.forename: Ola A
authors.initials: OA
authors.lastname: Selnes
authors.forename: Eileen
authors.initials: E
authors.lastname: Martin
authors.forename: Barbara R
authors.initials: BR
authors.lastname: Visscher
authors.forename: James T
authors.initials: JT
authors.lastname: Becker
mesh_terms: D015526:AIDS Dementia Complex / Q000150:complications / Q000473:pathology*; D000328:Adult; D001792:Blood Platelets / Q000166:cytology*; D001921:Brain / Q000473:pathology*; D018791:CD4 Lymphocyte Count; D018450:Disease Progression; D005500:Follow-Up Studies; D006678:HIV / Q000472:pathogenicity; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D059906:Neuroimaging; D009483:Neuropsychological Tests; D010976:Platelet Count; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies