Prospective evaluation of plasma phosphorylated tau in a real‐life memory clinic in Thailand

Abstract

Introduction: Despite the substantial accuracy of plasma p-tau in diagnosing Alzheimer's disease (AD) in research cohorts, data on real-life memory clinic patients are lacking. Methods:Memory clinic patients at their early symptomatic stages were prospectively enrolled to undergo routine clinical assessment, plasma p-tau181 quantification (Simoa), amyloid and tau-positron emission tomography (PET). The diagnostic performance of plasma p-tau181, neurocognitive specialists, and regional tau-PET were compared head-to-head using amyloid-PET as the reference standard.Results: Plasma p-tau181 has the area under the curve (AUC), sensitivity, specificity, and accuracy of 0.84 (95% confidence interval [CI] 0.73-0.94), 0.80 (95% CI 0.64-0.90), 0.75 (95% CI 0.51-0.90), and 0.78 (95% CI 0.65-0.88) for detecting amyloid-PET positivity in early symptomatic patients, respectively. The AUC of clinical diagnosis and tau-PET were 0.70 (95% CI 0.56-0.85) and 0.88 (95% CI 0.79-0.97), respectively. Discussion: Plasma p-tau181 also performed well in real-life memory clinic settings and its role in clinical practice is supported.

Predicting amyloid PET positivity using plasma p‐tau181 and other blood‐based biomarkers

“…37 Recently, the efficacy of blood-based biomarkers in predicting amyloid positivity, hippocampal atrophy and future cognitive stage transition in the Asian population has been reported. 29,38,39 However, it is still unclear how p-tau181 differs between ethnicities and validating the discriminative value of p-tau181 in a single ethnicity is also important. Second, a limited number of amyloid PET participants (41 in the MCI group and 23 in the dementia group) were analyzed in the current study.…”

“…In previous studies, including a study that analyzed the effect of p‐tau181 in a multi‐ethnic population, information on Asians was lacking 37 . Recently, the efficacy of blood‐based biomarkers in predicting amyloid positivity, hippocampal atrophy and future cognitive stage transition in the Asian population has been reported 29,38,39 . However, it is still unclear how p‐tau181 differs between ethnicities and validating the discriminative value of p‐tau181 in a single ethnicity is also important.…”

Multi-Omic Blood Biomarkers as Dynamic Risk Predictors in Late-Onset Alzheimer’s Disease

“…The robustness of plasma p-tau181 across ancestries was demonstrated by a prospective Spanish cohort study of 349 individuals (AUC = 0.96 for clinically diagnosed AD vs. cognitively unimpaired individuals) [118] and in a small Thai cohort study of 51 individuals (AUC = 0.84 [0.73-0.94]) [119]. However, p-tau181 performance was reduced among non-Hispanic White Americans (AUC = 0.69 [0.59-0.80]) and Black Americans (AUC = 0.63 [0.51-0.74]), and was considerably lower in Hispanic Americans (AUC = 0.51 [0.40-0.64]) [120].…”

“…Moreover, the p-tau181 result was understandable for 93% of clinicians and it informed AD diagnosis in 44% of cases. In a separate study of 51 patients attending a specialized Thai memory clinic, plasma p-tau181 collection and analysis was less expensive and just as accurate as an Aβ-PET scan (AUC = 0.84 [0.73-0.94]), indicating a more feasible means to measure biomarkers in this community [119]. Similarly, in a prospective study of over 350 patients attending a Spanish memory clinic, plasma p-tau181 demonstrated Class I evidence for correlation with AD [118].…”