Improving CSF biomarkers' performance for predicting progression from Mild Cognitive Impairment to Alzheimer's disease by considering different confounding factors: a meta-analysis

Background: Cerebrospinal fluid (CSF) biomarkers' performance for predicting conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD) is still suboptimal. Objective: By considering several confounding factors we aimed to identify in which situations these CSF biomarkers can be useful. DataSources: A systematic review was conducted on MEDLINE, PreMedline, EMBASE, PsycInfo, CINAHL, Cochrane, and CRD (1990-2013). Eligibility Criteria: (1) Prospective studies of CSF biomarkers' performance for predicting conversion from MCI to AD/ dementia; (2) inclusion of A beta 42 and T-tau and/or p-tau. Several meta-analyses were performed. Results: A beta 42/p-tau ratio had high capacity to predict conversion to AD in MCI patients younger than 70 years. The p-tau had high capacity to identify MCI cases converting to AD in <= 24months. Conclusions: Explaining how different confounding factors influence CSF biomarkers' predictive performance is mandatory to elaboratea definitive map of situations, where these CSF biomarkers are useful both in clinics and research.