Wenyaw Chan

Dr. Wenyaw Chan

orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 October 2009 in Alzheimer's Research & Therapy
Verified
Journal Article
Open access
PDF file
SRSusan D Rountree
Susan D Rountree
WCWenyaw Chan
Wenyaw Chan
VPValory N Pavlik
Valory N Pavlik
EDEveleen J Darby
Eveleen J Darby
SSSamina Siddiqui
Samina Siddiqui
RDRachelle S Doody
Rachelle S Doody
Introduction: There are no empiric data to support guidelines for duration of therapy with antidementia drugs. This study examined whether persistent use of antidementia drugs slows clinical progression of Alzheimer disease (AD) assessed by repeated measures on serial tests of cognition and function. Methods: Six hundred forty-one probable AD patients were followed prospectively at an academic center over 20 years. Cumulative drug exposure was expressed as a persistency index (PI) reflecting total years of drug use divided by total years of disease symptoms. Baseline and annual testing consisted of Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), Baylor Profound Mental Status Examination (BPMSE), Clinical Dementia Rating-Sum of Boxes (CDR-SB), Physical Self-Maintenance Scale (PSMS), and Instrumental Activities of Daily Living (IADL). Annual change in slope of neuropsychological and functional tests as predicted by follow-up time, PI, and the interaction of these two variables was evaluated. Results: PI was associated with significantly slower rates of decline (with, without adjustment for covariates) on MMSE (P < 0.0001), PSMS (P < 0.05), IADL (P < 0.0001), and CDR-SB (P < 0.001). There was an insignificant trend (P = 0.053) for the PI to be associated with slower rate of decline on BPMSE. The association of PI with ADAS-Cog followed a quadratic trend (P < 0.01). Analysis including both linear and quadratic terms suggests that PI slowed ADAS-Cog decline temporarily. The magnitude of the favorable effect of a rate change in PI was: MMSE 1 point per year, PSMS 0.4 points per year, IADL 1.4 points per year, and CDR-SB 0.6 points per year. The change in mean test scores is additive over the follow-up period (3 ± 1.94 years). Conclusions: Persistent drug treatment had a positive impact on AD progression assessed by multiple cognitive, functional, and global outcome measures. The magnitude of the treatment effect was clinically significant. Positive treatment effects were even found in those with advanced disease.

23 February 2010 in Alzheimer's Research & Therapy
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Journal Article
Open access
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RDRachelle S Doody
Rachelle S Doody
VPValory Pavlik
Valory Pavlik
PMPaul Massman
Paul Massman
SRSusan Rountree
Susan Rountree
EDEveleen Darby
Eveleen Darby
WCWenyaw Chan
Wenyaw Chan
Introduction: Clinicians need to predict prognosis of Alzheimer's disease (AD), and researchers need models of progression to develop biomarkers and clinical trials designs. We tested a calculated initial progression rate to see whether it predicted performance on cognition, function and behavior over time, and to see whether it predicted survival. Methods: We used standardized approaches to assess baseline characteristics and to estimate disease duration, and calculated the initial (pre-progression) rate in 597 AD patients followed for up to 15 years. We designated slow, intermediate and rapidly progressing groups. Using mixed effects regression analysis, we examined the predictive value of a pre-progression group for longitudinal performance on standardized measures. We used Cox survival analysis to compare survival time by progression group. Results: Patients in the slow and intermediate groups maintained better performance on the cognitive (ADAScog and VSAT), global (CDR-SB) and complex activities of daily living measures (IADL) (P values < 0.001 slow versus fast; P values < 0.003 to 0.03 intermediate versus fast). Interaction terms indicated that slopes of ADAScog and PSMS change for the slow group were smaller than for the fast group, and that rates of change on the ADAScog were also slower for the intermediate group, but that CDR-SB rates increased in this group relative to the fast group. Slow progressors survived longer than fast progressors (P = 0.024). Conclusions: A simple, calculated progression rate at the initial visit gives reliable information regarding performance over time on cognition, global performance and activities of daily living. The slowest progression group also survives longer. This baseline measure should be considered in the design of long duration Alzheimer's disease clinical trials.

7 January 2019 in Journal of Cardiovascular Magnetic Resonance
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Journal Article
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MKMohammad A. Khan
Mohammad A. Khan
EYEric Y. Yang
Eric Y. Yang
YZYang Zhan
Yang Zhan
RJRobert M. Judd
Robert M. Judd
WCWenyaw Chan
Wenyaw Chan
DSDipan J. Shah
Dipan J. Shah
Routine cine cardiovascular magnetic resonance (CMR) allows for the measurement of left atrial (LA) volumes. Normal reference values for LA volumes have been published based on a group of European individuals without known cardiovascular disease (CVD) but not on one of similar United States (US) based volunteers. Furthermore, the association between grades of LA dilatation by CMR and outcomes has not been established. We aimed to assess the relationship between grades of LA dilatation measured on CMR based on US volunteers without known CVD and all-cause mortality in a large, multicenter cohort of patients referred for a clinically indicated CMR scan. We identified 85 healthy US subjects to determine normal reference LA volumes using the biplane area-length method and indexed for body surface area (LAVi). Clinical CMR reports of patients with LA volume measures (n = 11,613) were obtained. Data analysis was performed on a cloud-based system for consecutive CMR exams performed at three geographically distinct US medical centers from August 2008 through August 2017. We identified 10,890 eligible cases. We categorized patients into 4 groups based on LAVi partitions derived from US normal reference values: Normal (21–52 ml/m2), Mild (52–62 ml/m2), Moderate (63–73 ml/m2) and Severe (> 73 ml/m2). Mortality data were ascertained for the patient group using electronic health records and social security death index. Cox proportional hazard risk models were used to derive hazard ratios for measuring association of LA enlargement and all-cause mortality. The distribution of LAVi from healthy subjects without known CVD was 36.3 ± 7.8 mL/m2. In clinical patients, enlarged LA was associated with older age, atrial fibrillation, hypertension, heart failure, inpatient status and biventricular dilatation. The median follow-up duration was 48.9 (IQR 32.1–71.2) months. On univariate analyses, mild [Hazard Ratio (HR) 1.35 (95% Confidence Interval [CI] 1.11 to 1.65], moderate [HR 1.51 (95% CI 1.22 to 1.88)] and severe LA enlargement [HR 2.14 (95% CI 1.81 to 2.53)] were significant predictors of death. After adjustment for significant covariates, moderate [HR 1.45 (95% CI 1.1 to 1.89)] and severe LA enlargement [HR 1.64 (95% CI 1.29 to 2.08)] remained independent predictors of death. LAVi determined on routine cine-CMR is independently associated with all-cause mortality in patients undergoing a clinically indicated CMR.

15 May 2012 in Alzheimer's Research & Therapy
Verified
Journal Article
Open access
PDF file
SRSusan D Rountree
Susan D Rountree
WCWenyaw Chan
Wenyaw Chan
VPValory N Pavlik
Valory N Pavlik
EDEveleen J Darby
Eveleen J Darby
RDRachelle S Doody
Rachelle S Doody
Introduction: This longitudinal study examined multiple factors that influence survival in a cohort of Alzheimer patients followed over two decades. Methods: Time to death after symptom onset was determined in 641 probable AD patients who were evaluated annually until death or loss to follow-up, and information was entered into a longitudinal database. Date of death was available for everyone including those eventually lost. Baseline variables included age, sex, race, disease severity, a calculated index of rate of initial cognitive decline from symptom onset to cohort entry (pre-progression rate or PPR), years of education, and medical comorbidities (diabetes, hypertension, hyperlipidemia, coronary disease, cerebrovascular disease). Multivariable Cox proportional hazard regression analysis was used to analyze the baseline and/or time dependent association in Mini-mental Status Exam (MMSE) severity, Physical Self Maintenance Scale (PSMS), Persistency Index (PI) of exposure to antipsychotic and antidementia drugs, and psychotic symptoms (hallucinations, delusions) with mortality. Results: Baseline covariates significantly associated with increased survival were younger age (p = .0016), female sex (p = .0001), and a slower PPR (p < .0001). Overall disease severity at baseline, medical comorbidities, and education did not influence time to death. Time-dependent changes in antipsychotic drug use, development of psychotic symptoms, antidementia drug use, and observed MMSE change were not predictive. In the final model the only time-dependent covariate that significantly decreased survival was worsening of functional ability on the PSMS (hazard ratio = 1.10; CI: 1.07-1.11). Conclusions: In this large AD cohort survival is influenced by age, sex, and the development of functional disability during follow-up. The most important predictor of mortality was a faster rate of cognitive decline at the initial patient visit (PPR). The currently available antidementia drugs do not prolong survival in Alzheimer patients.

1 April 2009 in Cancer Control
Verified
Journal Article
Open access
PDF file
LHLaurens Holmes
Laurens Holmes
WCWenyaw Chan
Wenyaw Chan
ZJZhidong Jiang
Zhidong Jiang
DWDoriel Ward
Doriel Ward
EEE. James Essien
E. James Essien
XDXianglin L. Du
Xianglin L. Du
Racial disparities persist in prostate cancer (CaP) treatment and survival, but disparities in androgen deprivation therapy (ADT) and the degree to which it affects racial differences in survival remains to be fully assessed. Using the Surveillance, Epidemiology and End Results-Medicare linked data, we examined a large cohort of men (N = 64,475) diagnosed with locoregional CaP during 1992 to 1999 and followed through 2003. The effects of ADT and race on survival were analyzed using a Cox proportional hazards model. The receipt of ADT was significantly lower in African Americans (24%) relative to Caucasians (27%), Asians (34%), and Hispanics (28.7%) (P < .05). Compared with Caucasian race, African American race was associated with a statistically significant increased mortality (HR = 1.26, 95% CI = 1.21-1.32), which remained significant after adjusting for ADT but was substantially decreased after controlling for primary therapies such as radical prostatectomy, radiation, and watchful waiting (HR = 1.06, 95% CI = 1.01-1.10) and was no longer statistically significant after controlling for comorbidities (HR = 0.98, 95% CI = 0.94-1.03). There were marked racial variations in the receipt of ADT, primary therapies (namely surgery and surgery combined with radiation), and comorbidities. However, racial disparities in survival were not affected by racial variations in ADT but were explained by racial variations in primary therapies and by racial differences in comorbidities.

1 April 2017 in Gynecologic Oncology
Verified
Journal Article
Closed access
DLDavid R Lairson
David R Lairson
SFShuangshuang Fu
Shuangshuang Fu
WCWenyaw Chan
Wenyaw Chan
LXLi Xu
Li Xu
ZSZeena Shelal
Zeena Shelal
LRLois Ramondetta
Lois Ramondetta