Role of Blood P-Tau Isoforms (181, 217, 231) in Predicting Conversion from MCI to Dementia Due to Alzheimer’s Disease: A Review and Meta-Analysis
Gemma Lombardi, Silvia Pancani, Riccardo Manca, Micaela Mitolo, Simone Baiardi, Federico Massa, Luigi Coppola, Monica Franzese, Emanuele Nicolai, Franca Rosa Guerini, Roberta Mancuso, Cristina Agliardi, Simone Agostini, Matteo Pardini, Gianni Virgili, Sandro Sorbi, Piero Parchi, Benedetta Nacmias, Annalena Venneri
Abstract
Blood-based biomarkers are minimally invasive tools to detect the pathological changes of Alzheimer's Disease (AD). This meta-analysis aims to investigate the use of blood-derived p-tau isoforms (181, 217, 231) to predict conversion from mild cognitive impairment (MCI) to AD dementia (ADD). Studies involving MCI patients with data on blood p-tau isoforms at baseline and clinical diagnosis at follow-up (≥1 year) were included. Twelve studies on p-tau 181 (4340 MCI, conversion rate 20.6%), four on p-tau 217 (913 MCI, conversion rate 33.4%), and one on p-tau 231 (135 MCI, conversion rate 33%) were included. For p-tau 181, the pooled area under the receiver operating characteristic curve (AUC) was 0.73 (95% CI = 0.68-0.78), and for p-tau 217 was 0.85 (95% CI = 0.75-0.91). Plasma levels of p-tau 181 had good discriminatory power to identify MCI patients who will convert to ADD. Although only four studies on p-tau 217 have been included in the meta-analysis, in the last year the predictive power of p-tau 217 is emerging as superior to that of other isoforms. However, given the high heterogeneity detected in the p-tau 217 studies included in this meta-analysis, additional supportive evidence is needed. Insufficient results were available for p-tau 231. These findings support the prognostic utility of p-tau 181 and p-tau 217 measured in blood to predict progression to ADD in MCI and encourage its future implementation in clinical practice.