Real-World Performance of Urine β-amyloid Test Kits in Multiple Hospital Clinics and Neighborhood Communities of China

Background: Growing evidence suggests that urinary {beta}-amyloid precursor protein (A{beta}PP) fragments can serve as an early screening biomarker for mild cognitive impairment and dementia. However, in reality, older adults, regardless of the presence of cognitive decline, often suffer from multiple age-related conditions and are on multiple medications. How these comorbidities and treatments affect the performance of early diagnostic biomarkers remains unclear. Methods : This study further validated the sensitivity, specificity, and clinical value of the Qankorey (R) urinary {beta}-amyloid protein detection kit in early dementia screening through a randomized community screening (n=51187) conducted in Changsha, and a multicenter case-control study conducted at Yuquan Hospital (Tsinghua University), Tiantan Hospital (Capital Medical University), Beijing Friendship Hospital, Zibo 148 Hospital (Shandong), and the Third People's Hospital of Yunnan Province. The multicenter case-control study included 898 participants, comprising 266 healthy, age-matched controls without any comorbidities, 167 patients with mild cognitive impairment/Alzheimer's disease (MCI/AD), and 465 non-AD patients with various comorbidities and age-related diseases. Results: The kit showed a significant age-dependent positive rate in both men and women in Changsha, increasing from 6.29% to 15.40%. The number of weakly positive/positive/negative individuals in the healthy group, non-AD group, and MCI/AD group were 8/12/246 (positive rate 7.52%), 41/16/409 (12.23%), and 77/44/46 (72.46%), respectively, with a Kappa value of 0.669, indicating that the method performed well in the clinical diagnosis of MCI/AD, consistent with previously published results. Among the 8 weakly positive healthy subjects, 6 were found to have brain abnormalities by MRI/CT examination. Comorbidity analysis showed that memory decline was the most significant risk factor (P=9.6 x 10^-23, Fisher's exact test), followed by dizziness (P=1.3 x 10^-14;) , hyperlipidemia (P=3.2 x 10^-12) , history of stroke (P=0.0011), and hypertension (P=0.0058). Treatment analysis showed that cardiovascular drugs and antithrombotic drugs significantly reduced the risk of dementia (P values were 0.0061 and 0.0081, respectively), followed by hypoglycemic drugs (P=0.0358). For AD patients, those receiving only memantine showed a slightly lower positive test rate (P=0.0532). Conclusion: Our findings confirm the diagnostic value of urinary {beta}-amyloid protein detection in MCI and AD-related dementia. Furthermore, this kit can be used in practical clinical applications to assess the risk of cognitive decline and treatment efficacy across various diseases.