Browsing by Author "Ren, Xuehan"
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Item Open Access Analysis of antepartum obstetric triage utilization at 24 weeks and beyond(AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY, 2021-02) Ren, Xuehan; Jelovsek, Eric; Luo, Sheng; Hughes, Brenna L; Reiff, EmilyItem Open Access Dynamic prediction using joint models of longitudinal and recurrent event data: a Bayesian perspective(Biostatistics and Epidemiology, 2019-01-01) Ren, Xuehan; Wang, Jue; Luo, Sheng© 2019, © 2019 International Biometric Society–Chinese Region. In cardiovascular disease (CVD) studies, the events of interest may be recurrent (multiple occurrences from the same individual). During the study follow-up, longitudinal measurements are often available and these measurements are highly predictive of event recurrences. It is of great clinical interest to make personalized prediction of the next occurrence of recurrent events using the available clinical information, because it enables clinicians to make more informed and personalized decisions and recommendations. To this end, we propose a joint model of longitudinal and recurrent event data. We develop a Bayesian approach for model inference and a dynamic prediction framework for predicting target subjects' future outcome trajectories and risk of next recurrent event, based on their data up to the prediction time point. To improve computation efficiency, embarrassingly parallel MCMC (EP-MCMC) method is utilized. It partitions the data into multiple subsets, runs MCMC sampler on each subset, and applies random partition trees to combine the posterior draws from all subsets. Our method development is motivated by and applied to the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), one of the largest CVD studies to compare the effectiveness of medications to treat hypertension.Item Open Access Missing Data in the Unified Dysksinesia Rating Scale (UDysRS).(Movement disorders clinical practice, 2018-09) Luo, Sheng; Ren, Xuehan; Han, Weilu; Goetz, Christopher G; Stebbins, Glenn TIdentify the number of allowable missing values still permitting valid surrogate score calculation for the Unified Dyskinesia Rating Scale (UDysRS). Missing data frequently occur in Parkinson's disease rating scales, and they compromise data validity, risking data exclusion from final analyses. Accessing the International Parkinson and Movement Disorder Society-sponsored UDysRS translation databases (3313 complete scores). We sequentially removed item scores, consistently or randomly from subjective and objective sections. Lin's Concordance Correlation Coefficient compared prorated scores with complete scores. We considered prorated scores valid when Coefficients exceeded 0.95. For consistently missing items, three from the subjective section and five from the objective section are allowable. For randomly missing items, seven from the subjective section and four from the objective section are permissible. We provide guidelines for constructing valid surrogate summary UDysRS scores with clear thresholds for retaining or rejecting scores based on missing values.Item Open Access Prognostic Modeling of Parkinson's Disease Progression Using Early Longitudinal Patterns of Change.(Movement disorders : official journal of the Movement Disorder Society, 2021-07-30) Ren, Xuehan; Lin, Jeffrey; Stebbins, Glenn T; Goetz, Christopher G; Luo, ShengBackground
Predicting Parkinson's disease (PD) progression may enable better adaptive and targeted treatment planning.Objective
Develop a prognostic model using multiple, easily acquired longitudinal measures to predict temporal clinical progression from Hoehn and Yahr (H&Y) stage 1 or 2 to stage 3 in early PD.Methods
Predictive longitudinal measures of PD progression were identified by the joint modeling method. Measures were extracted by multivariate functional principal component analysis methods and used as covariates in Cox proportional hazards models. The optimal model was developed from the Parkinson's Progression Marker Initiative (PPMI) data set and confirmed with external validation from the Longitudinal and Biomarker Study in PD (LABS-PD) study.Results
The proposed prognostic model with longitudinal information of selected clinical measures showed significant advantages in predicting PD temporal progression in comparison to a model with only baseline information (iAUC = 0.812 vs. 0.743). The modeling results allowed the development of a prognostic index for categorizing PD patients into low, mid, and high risk of progression to HY 3 that is offered to facilitate physician-patient discussion on prognosis.Conclusion
Incorporating longitudinal information of multiple clinical measures significantly enhances predictive performance of prognostic models. Furthermore, the proposed prognostic index enables clinicians to classify patients into different risk groups, which could be adaptively updated as new longitudinal information becomes available. Modeling of this type allows clinicians to utilize observational data sets that inform on disease natural history and specifically, for precision medicine, allows the insertion of a patient's clinical data to calculate prognostic estimates at the individual case level. © 2021 International Parkinson and Movement Disorder Society.Item Open Access Successful use of the Unified Dyskinesia Rating Scale regardless of PD- or dyskinesia-duration.(Parkinsonism & related disorders, 2019-10) Ren, Xuehan; Lin, Jeffrey; Luo, Sheng; Goetz, Christopher G; Stebbins, Glenn T; Cubo, EstherOBJECTIVE:We assessed differential item functioning (DIF) in the Unified Dyskinesia Rating Scale (UDysRS) to evaluate bias risk from the duration of Parkinson's Disease (PD) and duration of dyskinesia. BACKGROUND:Assessing DIF is a core validation step for rating scales. If DIF is present for an item, interpretation must consider influences from the tested covariates. DIF can be uniform or non-uniform, depending on the consistency of influence from the given covariate across all levels of dyskinesia. METHODS:Using a large UDysRS database (N = 2313), uniform and non-uniform DIF related to the duration of PD and/duration of dyskinesia were tested. Unidimensionality of UDysRS was first confirmed using confirmatory factor analysis. DIF analysis was conducted using two independent latent models. DIF in an item was confirmed if both methods independently identified DIF at a significance level using Bonferroni correction. McFadden pseudo R^2 measured clinical relevancy of DIF magnitude (negligible, moderate, and large) for items identified with DIF, and items with DIF were considered clinically relevant if they exceeded a negligible designation. RESULTS:Most items did not show uniform or non-uniform DIF based on PD and dyskinesia duration in isolation or in combination. For all items where DIF was identified, the magnitude statistic was in the negligible range (McFadden pseudo R^2 < 0.035) and the combined impact of multiple identified DIF items on UDysRS likewise did not exceed the negligible designation. CONCLUSION:The absence of clinically relevant DIF suggests that the UDysRS can be applied across all patients regardless of their PD- or dyskinesia-duration.Item Open Access Validation of the Hebrew Version of the Unified Dyskinesia Rating Scale.(Neuroepidemiology, 2020-06-15) Faust-Socher, Achinoam; Anis, Saar; Kestenbaum, Meir; Shabtai, Herzl; Taichman, Tali; Bar David, Aya; Ezra, Adi; Peretz, Chava; Rosenberg, Alina; Brozgol, Marina; Herman, Talia; Stebbins, Glenn T; Goetz, Christopher G; Martínez-Martín, Pablo; Luo, Sheng T; Ren, Xuehan; Giladi, Nir; Gurevich, TanyaBACKGROUND:The Unified Dyskinesia Rating Scale (UDysRS) is a well-established tool for producing comprehensive assessments of severity and disability associated with dyskinesia in patients with Parkinson's disease (PD). The scale was originally developed in English, and a broad international effort has been undertaken to develop and validate versions in additional languages. Our aim was to validate the Hebrew version of the UDysRS. METHODS:We translated the UDysRS into Hebrew, back-translated it into English, and carried out cognitive pretesting. We then administered the scale to non-demented native Hebrew-speaking patients who fulfilled the Brain Bank diagnostic criteria for probable PD (n = 250). Data were compared to the Reference Standard data used for validating UDysRS translations. RESULTS:The different portions of the Hebrew UDysRS showed high internal consistency (α ≥ 0.92). A confirmatory factor analysis in which we compared the Hebrew UDysRS to the Reference Standard version produced a comparative fit index (CFI) of 0.98, exceeding the threshold criterion of CFI > 0.9 indicating factor validity. A secondary exploratory factor analysis provided further support to the consistency between the factor structures of the Hebrew and Reference Standard versions of the UDysRS. CONCLUSION:The UDysRS Hebrew version shows strong clinimetric properties and fulfills the criteria for designation as an official International Parkinson and Movement Disorder Society-approved translation for use in clinical and research settings.Item Open Access Validation of the Polish version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS).(Neurologia i neurochirurgia polska, 2020-07-08) Siuda, Joanna; Boczarska-Jedynak, Magdalena; Budrewicz, Sławomir; Dulski, Jarosław; Figura, Monika; Fiszer, Urszula; Gajos, Agata; Gorzkowska, Agnieszka; Koziorowska-Gawron, Ewa; Koziorowski, Dariusz; Krygowska-Wajs, Anna; Rudzińska-Bar, Monika; Sławek, Jarosław; Ren, Xuehan; Luo, Sheng; Martinez-Martin, Pablo; Stebbins, Glenn; Goetz, Christopher G; Opala, Grzegorz; MDS-UPDRS Polish Validation Task ForceBACKGROUND:In 2008, the Movement Disorders Society (MDS) published a new Unified Parkinson's Disease Rating Scale (MDS-UPDRS) as the official benchmark scale for Parkinson's Disease (PD). We have translated and validated the Polish version of the MDS-UPDRS, explored its dimensionality, and compared it to the original English one. METHODS:The MDS-UPDRS was translated into Polish by a team of Polish investigators led by JS and GO. The back-translation was completed by colleagues fluent in both languages (Polish and English) who were not involved in the original translation, and was reviewed by members of the MDS Rating Scales Programme. Then the translated version of the MDS-UPDRS underwent cognitive pretesting, and the translation was modified based on the results. The final translation was approved as the Official Working Document of the MDS-UPDRS Polish version, and was tested on 355 Polish PD patients recruited at movement disorders centres all over Poland (at Katowice, Gdańsk, Łódź, Warsaw, Wrocław, and Kraków). Confirmatory and explanatory factor analyses were applied to determine whether the factor structure of the English version could be confirmed in the Polish version. RESULTS:The Polish version of the MDS-UPDRS showed satisfactory clinimetric properties. The internal consistency of the Polish version was satisfactory. In the confirmatory factor analysis, all four parts had greater than 0.90 comparative fit index (CFI) compared to the original English MDS-UPDRS. Explanatory factor analysis suggested that the Polish version differed from the English version only within an acceptable range. CONCLUSIONS AND CLINICAL IMPLICATIONS:The Polish version of the MDS-UPDRS meets the requirements to be designated as the Official Polish Version of the MDS-UPDRS, and is available on the MDS web page. We strongly recommend using the MDS-UPDRS instead of the UPDRS for research purposes and in everyday clinical practice.Item Open Access Validation of the Thai Version of the Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale.(Journal of movement disorders, 2022-03-16) Jagota, Priya; Srivanitchapoom, Prachaya; Petchrutchatachart, Sitthi; Singmaneesakulchai, Surat; Pisarnpong, Apichart; Lolekha, Praween; Setthawatcharawanich, Suwanna; Chairangsaris, Parnsiri; Limotai, Natlada; Mekawichai, Pawut; Panyakaew, Pattamon; Phokaewvarangkul, Onanong; Sringean, Jirada; Pitakpatapee, Yuvadee; LaPelle, Nancy; Martinez-Martin, Pablo; Ren, Xuehan; Luo, Sheng; Stebbins, Glenn T; Goetz, Christopher G; Bhidayasiri, RoongrojObjective
This study aims to validate the Thai translation of the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS).Methods
The English version was translated into Thai and then back-translated into English. The translated version underwent 2 rounds of cognitive pretesting to assess the ease of comprehension, ease of use and comfort with the scale. Then, it underwent large clinimetric testing.Results
The Thai version was validated in 354 PD patients. The comparative fit index (CFI) for all four parts of the Thai version of the MDS-UPDRS was 0.93 or greater. Exploratory factor analysis identified isolated item differences in factor structure between the Thai and English versions.Conclusion
The overall factor structure of the Thai version was consistent with that of the English version based on the high CFIs (all CFI ≥ 0.90). Hence, it can be designated the official Thai version of the MDS-UPDRS.