A screening algorithm for HIV‐associated neurocognitive disorders

Abstract

BackgroundHIV physicians have limited time for cognitive screening. Here we developed an extra-brief, clinically based tool for predicting HIV-associated neurocognitive impairment (HAND) in order to determine which HIV-positive individuals require a more comprehensive neurological/ neuropsychological (NP) assessment. MethodsNinety-seven HIV-positive individuals with advanced disease recruited in an HIV out-patient clinic received standard NP testing. A screening algorithm was developed using support vector machines, an optimized prediction procedure for classifying individuals into two groups (here NP-impaired and NP-normal) based on a set of predictors. ResultsThe final algorithm utilized age, current CD4 cell count, past central nervous system HIV-related diseases and current treatment duration and required approximately 3 min to complete, with a good overall prediction accuracy of 78% (against the gold standard; NP-impairment status derived from standard NP testing) and a good specificity of 70%. ConclusionThis noncognitive-based algorithm should prove useful to identify HIV-infected patients with advanced disease at high risk of HAND who require more formal assessment. We propose staged guidelines, using the algorithm, for improved HAND therapeutic management. Future larger, international studies are planned to test the predictive effect of nadir CD4 cell count, hepatitis C virus infection, gender, ethnicity and HIV viral clade. We recommend the use of this first version for HIV-infected Caucasian men with advanced disease.Keywords: antiretroviral therapy, diagnosis algorithm, HIV/AIDS, HIV-associated neurocognitive disorder, mathematical model Accepted 21 January 2010 IntroductionThe clinical management of HIV-positive persons is increasingly complicated in the era of combination antiretroviral therapy (CART). One aspect of management that requires extensive training relates to the early identification of neurocognitive complications of HIV infection. In many countries the general practitioner or the HIV physician is often the primary patient's interlocutor [1]. Without specific screening using procedures that are still relatively lengthy or require specific training, especially for interpretation [2], physicians may sometimes overlook patients in need of further neurological evaluation.In the CART era, the prevalence of neurocognitive impairment remains high (up to 50% [3]) and HIVassociated neurocognitive disorder (HAND) has shifted towards a milder clinical presentation [4]. Such a mild clinical presentation can escape detection without formal neurological assessment and neuropsychological testing [5]. HAND, even in its mild form, is independently predictive of death [6] The development of the screening algorithm was based on support vector machine (SVM) methodology. Because the aim of our study was to provide a simplified algorithm from a complex set of predictors, SVM was the most appropriate procedure [18]. The SVM has been shown to be extremely robust in solving prediction problems while handling la...

Genotypical diversity of HIV clades and central nervous system impairment

“…Such mild clinical presentations can escape detection without formal neurological assessment and neuropsychological testing 34 . Short term outcomes include significant impact on independence in all aspects of daily life, including employment 43 , and perhaps most importantly, medication adherence 44 . HIV encephalitis is characterized by a number of individually nonspecific neuropathological features (white matter pallor, microglial nodules, multinucleated giant cells, and gliosis).…”

HIV-associated neurocognitive disorders: a changing pattern

“…Certainly, one important challenge relates to the early detection of HANDs in stable and cART-treated patients, and this is especially true for the physicians taking care of HIV + patients in their daily practice. Recently, Cysique et al proposed a brief algorithm to identify patients at risk of HANDs [69]. This algorithm was developed on a sample of patients with advanced HIV (stage C3 according to the Centers for Disease Control and Prevention [CDC] classification) and based on variables that have been documented as risk factors for HANDs: age, educational level, plasma viral load, past history of CNS opportunistic infection, hemoglobin levels, HIV duration, cART CNS penetration characteristics and duration of current cART [69].…”

“…This algorithm was developed on a sample of patients with advanced HIV (stage C3 according to the Centers for Disease Control and Prevention [CDC] classification) and based on variables that have been documented as risk factors for HANDs: age, educational level, plasma viral load, past history of CNS opportunistic infection, hemoglobin levels, HIV duration, cART CNS penetration characteristics and duration of current cART [69]. The reported sensitivity and specificity of this algorithm were 78 and 70%, respectively, for the identification of patients with HANDs [69].…”

Evidence-based perspectives on the implementation of screening for neurocognitive impairment in HIV

“…124 One possible strategy that has not been addressed in clinical research is selective screening, limited to patients at high risk of HAND, such as those with a lower nadir CD4 count or other risk factors. 129,130 After many years of research, we still lack a suitable screening tool for HAND. The HDS lacks sensitivity, and the IHDS lacks specificity; neither has been tested in a wide enough cultural context.…”