Efficacy of the Phosphorylated tau 181 in Differential Diagnosis of the Alzheimer's Disease: A Systematic Review and Meta-Analysis

Abstract

Background: The purpose of this study was to evaluate the value of phosphorylated tau with epitopes threonine 181(p-tau181) in cerebrospinal fluid (CSF) for the differential diagnosis of Alzheimer's disease typed dementia from other type of dementia. Methods: A systematic literature search was performed to identify studies on p-tau181. Two evaluators independently evaluated the quality of the ten studies using the Scottish Intercollegiate Guidelines Network (SIGN) tool. The literature review covered from October 27, 1946 to October 22, 2013, and eight domestic databases including KoreaMed and international data- bases including Ovid-MEDLINE, EMBASE, and Cochrane Library were used. Tau concentrations were compared to healthy controls and to subjects with Alzheimer's disease (AD) using random effect meta- analysis. Outcome measures were Cohen's delta, sensitivity and specificity. Results: Finally, 8 studies (8 diagnostic evaluation studies) were identified to evaluate CSF p-tau181. The effectiveness of this test was evaluated based on diagnostic accuracy. The diagnostic accuracy for identifying AD by ELISA was high which revealed pooled sensitivity as 0.843 (95% CI 0.818-0.867), pooled specificity as 0.799(95% CI 0.768-0.828) and summary receiver operating characteristic area under the curve 0.9082 ± 0.0236. Con- clusions: CSF p-tau181 concentrations in other type of dementia are intermediate between controls and AD patients. Overlap between both controls and AD patients results in insufficient diagnostic accuracy, and the development of more specific biomarkers for these disorders is needed.