Affiliations: [a]
Taub Institute, Columbia University Medical, New York, NY, USA
| [b] Division of Biostatistics, Columbia University Medical Center, New York, NY, USA
| [c]
Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| [d]
Department of Psychiatry, Columbia University Medical Center, New York, NY, USA
| [e]
Departments of Medicine and Epidemiology, Columbia University Medical Center, New York, NY, USA
Correspondence:
[*]
Correspondence to: William C. Kreisl, MD, Taub Institute, Columbia University Medical Center, 622W. 168th Street, PH 19th Floor, New York, NY10032, USA. Tel.: +1 212 305 9194; Fax: +1 212 305 2426; E-mail: wck2107@cumc.columbia.edu.
Abstract: Background:Odor identification deficits occur in Alzheimer’s disease (AD), as measured by the 40-item University of Pennsylvania Smell Identification Test (UPSIT). Objective:To determine if UPSIT scores predict amyloid-β (Aβ) status, determined by 11C-Pittsburgh Compound B PET. We also compared UPSIT scores to Aβ status in predicting future memory decline. Methods:Subjects were recruited into a longitudinal clinical prediction study. We analyzed data from those who had UPSIT, cognitive testing, PIB PET, and at least 12 months’ clinical follow-up. Forty-six amnestic mild cognitive impairment patients and 25 cognitively normal controls were included. Amyloid-positivity was defined as composite PIB standardized uptake value ratio >1.5. Logistic regression and Receiver Operating Characteristic Curve analyses tested the predictive utility of impaired olfaction (defined as UPSIT score <35) and amyloid-positivity for memory decline. Results:High UPSIT scores predicted absence of amyloidosis on PET, with negative predictive value of 100%. Positive predictive value of low UPSIT scores on positive Aβ status was only 41%. Both low UPSIT score (OR = 4.301, 95% CI = 1.248, 14.821, p = 0.021) and positive PET scan (OR = 20.898, 95% CI = 2.222, 196.581, p = 0.008) predicted memory decline. Conclusion:Individuals with high UPSIT scores are less likely to have cerebral amyloidosis or experience memory decline. Therefore, UPSIT has potential as a screening tool to determine utility of Aβ PET in clinical practice or enrollment in clinical trials. Low UPSIT score is a non-specific marker of neurodegeneration that could indicate further workup in patients with memory complaints.
