HIV Patients With Declining Platelet Counts Have Raised Risk For Dementia

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Main Category: HIV / AIDS
Also Included In: Alzheimer's / Dementia;  Blood / Hematology;  Clinical Trials / Drug Trials
Article Date: 11 Sep 2007 - 9:00 PDT

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An HIV patient whose platelet counts (the number of clotting cells in the blood) are declining is probably more likely to suffer from HIV-associated dementia, says an article in Archives of Neurology (JAMA/Archives), September issue.

The report states "human immunodeficiency virus-associated dementia (HIV-D) is a syndrome encompassing a spectrum of cognitive, behavioral and motor deficits that usually has an insidious onset and a chronic progressive course,"

Paradoxically, the very treatment that helps HIV patients live longer exposes them to a higher risk of this condition. In order to diagnose HIV-associated dementia and to understand its underlying mechanisms it is critical to be able to identify the biological markers, say the authors.

Lynn M. Wachtman, D.V.M., M.P.H., Bloomberg School of Public Health, The Johns Hopkins University School of Medicine, Baltimore, and team looked at 396 people with advanced HIV who took part in this prospective study during the period 1998-2003. The patients were checked every six months and underwent physical and mental evaluations. They also had a blood test each time so that their platelet count could be assessed, as well as hemoglobin levels, CD4 lymphocyte count and plasma HIV RNA levels.

31.1 months into the study, at its median point, 40 patients had developed HIV-associated dementia. The researchers found that a fall in platelet count from baseline was linked to the development of dementia from within six months to one year. They wrote "Those HIV-infected individuals with a decline in platelets from baseline values at this lagged time point had a two-fold increased risk of dementia." The timing of the link indicates that levels of circulating platelets vary as HIV-associated dementia develops.

The researchers added "Further analyses indicated that decline from baseline platelet levels was associated with a five- to six-fold increased risk of dementia during the first two years of follow-up, but it was not associated with an increased risk of dementia after two years. It is possible that individuals who do not progress rapidly to neurologic compromise differ in respect to immune activation, treatment adherence or virologic control relative to those who develop dementia more rapidly."

The authors concluded "Because CD4 cell counts and HIV RNA levels have proven not to be predictive of HIV-associated dementia, it is important to investigate alternative serum and hematologic markers. Should these markers be routinely measured in a clinical setting, such as platelet counts, they may prove useful for patient management. This study identifies a significant association between platelet decline and incident HIV-associated dementia."

"Platelet Decline - An Avenue for Investigation Into the Pathogenesis of Human Immunodeficiency Virus-Associated Dementia"
Lynn M. Wachtman, DVM, MPH; Richard L. Skolasky, MA; Patrick M. Tarwater, PhD; Deneen Esposito, BA; Giovanni Schifitto, MD; Karen Marder, MD, MPH; Michael P. McDermott, PhD; Bruce A. Cohen, MD; Avindra Nath, MD; Ned Sacktor, MD; Leon G. Epstein, MD; Joseph L. Mankowski, DVM, PhD; Justin C. McArthur, MBBS, MPH
Arch Neurol. 2007;64:1264-1272.
Click here to view abstract online

Written by: Christian Nordqvist
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