Real-world performance of plasma p-tau181 in a heterogeneous memory clinic cohort.

OBJECTIVE: In light of clinical trials and disease-modifying therapies, an early identification of patients at-risk of developing Alzheimer's disease (AD) is crucial. Blood-based biomarkers have shown promising results regarding the in vivo detection of the earliest neuropathological changes in AD. Herein, we investigated the ability of plasma p-tau181 to act as a prescreening marker for amyloid positivity in a heterogeneous memory clinic-based cohort. METHODS: In this retrospective cross-sectional study, we included a total of 115 patients along the clinical AD continuum (mild cognitive impairment [MCI] due to AD, n = 62, probable AD dementia, n = 53). Based on their biomarker status, they were stratified into an amyloid-positive (Aß+, n = 88) or amyloid-negative cohort (Aß-, n = 27). Plasma and CSF p-tau181 concentrations were quantified using an ultrasensitive single-molecule array (SIMOA©). Furthermore, age- and sex-adjusted receiver operating characteristic (ROC) curves were calculated and the area under the curve (AUC) of each model was compared using DeLong's test for correlated AUC curves. RESULTS: The median (interquartile range [IQR]) concentration of plasma p-tau181 was significantly higher in Aß+ patients (3.6 pg/mL [2.5-4.6]), compared with Aß- patients (1.7 pg/mL [1.2-1.9], p < 0.001). Regarding the distinction between Aß+ and Aß- patients and the prediction of amyloid positivity, a high diagnostic accuracy for plasma p-tau181 with an AUC of 0.89 (95% CI = 0.82-0.95) was calculated. Adding the risk factors, age and APOE4, to the model did not significantly improve its performance. INTERPRETATION: Our findings demonstrate that plasma p-tau181 could be a noninvasive and feasible prescreening marker for amyloid positivity in a heterogeneous clinical AD cohort and therefore help in identifying those who would benefit from more invasive assessment of amyloid pathology.

The Epidemiological Transition of Surgically Treated Proximal Hip Fractures in Austria over the Course of the Pandemic-Back to Normal or a New Normal?

BACKGROUND: The COVID-19 pandemic has had a significant impact on the treatment protocols of orthopedic and trauma departments, but its specific effect on the mortality of hip fracture patients due to possible delays in surgery remains uncertain. This study aimed to investigate whether the COVID-19 pandemic worsened the mortality of patients with hip fractures. MATERIALS AND METHODS: This study included 246 prospectively enrolled patients who suffered from hip fractures during the Austrian State of Emergency period between 1 March and 30 June 2020 and 2021 and were admitted to a tertiary care trauma center. This cohort was compared with a retrospective control group of 494 patients admitted for hip fractures during the same timeframe in 2017, 2018, and 2019. These groups were compared to a prospective recruited "post-COVID-19 collective consisting of the years 2022 and 2023 including 313 patients. RESULTS: This study found a 22% reduction in admissions during the COVID-19 period compared to the pre-COVID period (p = 0.018), as well as significant changes in gender (p = 0.013) and place of accident (p = 0.049). No other changes in demographic variables were observed. The 30-day mortality rate was 14.67% in the pre-COVID period, compared to 15.18% during the COVID-19 period (p = 0.381). No differences were observed in surgical complication rates or in the relationship between comorbidity burden and survival. CONCLUSION: This study did not show a higher perioperative mortality rate due to COVID-19. However, under current circumstances, with potentially reduced surgical and hospital bed capacities, it is expected that this condition might require a high degree of resources in times when resources are potentially scarce, such as during an ongoing pandemic. LEVEL OF EVIDENCE: Level III.