מושגי ליבה
Blood biomarkers amyloid beta (Aβ) and tau protein are highly accurate in identifying Alzheimer's disease (AD) in patients with cognitive symptoms, outperforming clinical evaluations by primary care physicians and dementia specialists.
תקציר
The study examined the diagnostic accuracy of blood biomarkers for Alzheimer's disease (AD) in primary and secondary care settings. Researchers analyzed plasma samples from two cohorts of patients with cognitive symptoms to assess the performance of amyloid beta (Aβ) and tau protein biomarkers.
Key findings:
- The blood biomarker test had an accuracy of 91% in correctly classifying clinical, biomarker-verified AD, compared to 61% accuracy for primary care physicians and 73% for dementia specialists based on standard clinical evaluations.
- The blood test achieved very high positive predictive values (97-99%) in patients with cognitive impairment, the target population for anti-amyloid treatments.
- The negative predictive values were also high (87-92%), indicating the blood test can be useful for ruling out underlying AD in patients with only subtle symptoms.
- The diagnostic accuracy of the blood tests was on par with FDA-cleared cerebrospinal fluid biomarkers, but blood tests are more convenient and cost-effective for patients.
- The researchers emphasize that the blood tests should complement, not replace, the standard clinical evaluation, as Alzheimer's pathology can be asymptomatic for years and cognitive symptoms may result from other conditions.
- Implementing these blood tests could lead to more accurate and earlier diagnoses of AD, potentially improving treatment outcomes.
סטטיסטיקה
Primary care physicians had a diagnostic accuracy of 61% (95% CI, 53%-69%) for identifying clinical AD, compared to 91% (95% CI, 86%-96%) using the blood test.
Dementia specialists had a diagnostic accuracy of 73% (95% CI, 68%-79%) for identifying clinical AD, compared to 91% (95% CI, 86%-95%) using the blood test.
In the overall population, the diagnostic accuracy using the amyloid probability score 2 (APS2) was 90% (95% CI, 88%-92%), which was not different from using the percentage of phosphorylated tau 217 (p-tau217) alone (90%; 95% CI, 88%-91%).
ציטוטים
"This underscores the potential improvement in diagnostic accuracy, especially in primary care, when implementing such a blood test."
"Seeing that the test was just as accurate in primary care (about 90%) as it was in secondary care is really encouraging, especially since primary care is the first, and often final, point of entry into the healthcare system for cognitive evaluations."
"This could potentially result in a better response to treatment. Results from drug trials clearly indicate that the earlier treatment begins, the more effectively it can slow disease progression."