, according to research published online ahead of print May 6 in JAMA Neurology. Levels of total tau in plasma and CSF are correlated, and plasma total tau is associated with survival time. These findings suggest that plasma total tau level could be a valid biomarker that guides clinical care for patients with sporadic Creutzfeldt-Jakob disease, said the investigators.
Dr. Adam Staffaroni
The accurate prediction of disease duration can assist clinicians and caregivers in clinical management, as well as influence the design of clinical trials. Previous studies have found that baseline protein levels in CSF and plasma are associated with disease duration in patients with sporadic Creutzfeldt-Jakob disease. To replicate these findings, Adam M. Staffaroni, PhD, of the department of neurology at the University of California, San Francisco, and colleagues conducted a longitudinal cohort study.
Evaluating fluid and nonfluid biomarkers
Dr. Staffaroni and colleagues recruited 193 participants with probable or definite sporadic Creutzfeldt-Jakob disease who had codon 129 genotyping and were referred to the UCSF Memory and Aging Center from March 2004 to January 2018. All participants underwent cognitive testing, informant measures, a neurologic examination, and CSF and blood sample collection. The researchers excluded from analysis five participants who had been placed on life-extending treatments. Participants were evaluated until death or censored at the time of statistical analysis.
Dr. Staffaroni and colleagues examined the following nonfluid biomarkers of survival: sex, age, codon 129 genotype, Barthel Index, and Medical Research Council (MRC) Prion Disease Rating Scale. In addition, they examined total tau level, phosphorylated tau level, total tau:phosphorylated tau ratio, neurofilament light (NfL) level, beta-amyloid 42 level, neuron-specific enolase level, 14-3-3 test result, and real-time quaking-induced conversion test in CSF as fluid biomarkers of survival. Finally, Dr. Staffaroni’s group analyzed total tau level, NfL level, and glial fibrillary acidic protein level in plasma as additional fluid biomarkers of survival.
The researchers fitted Cox proportional hazard models with time to event as the outcome. They log-transformed fluid biomarkers and ran models with and without nonfluid biomarkers of survival.