Biomaterial Database

Risk-adjusted survival time monitoring with an updating exponentially weighted moving average (EWMA) control chart. 2010

Stefan H Steiner, and Mark Jones

Department of Statistics and Actuarial Sciences, University of Waterloo, Waterloo, Ontario, Canada. shsteine@uwaterloo.ca

Monitoring medical outcomes is desirable to help quickly detect performance changes. Previous applications have focused mostly on binary outcomes, such as 30-day mortality after surgery. However, in many applications the survival time data are routinely collected. In this paper, we propose an updating exponentially weighted moving average (EWMA) control chart to monitor risk-adjusted survival times. The updating EWMA (uEWMA) operates in a continuous time; hence, the scores for each patient always reflect the most up-to-date information. The uEWMA can be implemented based on a variety of survival-time models and can be set up to provide an ongoing estimate of a clinically interpretable average patient score. The efficiency of the uEWMA is shown to compare favorably with the competing methods.

UI	MeSH Term	Description	Entries
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D006348	Cardiac Surgical Procedures	Surgery performed on the heart.	Cardiac Surgical Procedure,Heart Surgical Procedure,Heart Surgical Procedures,Procedure, Cardiac Surgical,Procedure, Heart Surgical,Procedures, Cardiac Surgical,Procedures, Heart Surgical,Surgical Procedure, Cardiac,Surgical Procedure, Heart,Surgical Procedures, Cardiac,Surgical Procedures, Heart
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D015233	Models, Statistical	Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.	Probabilistic Models,Statistical Models,Two-Parameter Models,Model, Statistical,Models, Binomial,Models, Polynomial,Statistical Model,Binomial Model,Binomial Models,Model, Binomial,Model, Polynomial,Model, Probabilistic,Model, Two-Parameter,Models, Probabilistic,Models, Two-Parameter,Polynomial Model,Polynomial Models,Probabilistic Model,Two Parameter Models,Two-Parameter Model
D016019	Survival Analysis	A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.	Analysis, Survival,Analyses, Survival,Survival Analyses
D016896	Treatment Outcome	Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.	Rehabilitation Outcome,Treatment Effectiveness,Clinical Effectiveness,Clinical Efficacy,Patient-Relevant Outcome,Treatment Efficacy,Effectiveness, Clinical,Effectiveness, Treatment,Efficacy, Clinical,Efficacy, Treatment,Outcome, Patient-Relevant,Outcome, Rehabilitation,Outcome, Treatment,Outcomes, Patient-Relevant,Patient Relevant Outcome,Patient-Relevant Outcomes
D020379	Risk Adjustment	The use of severity-of-illness measures, such as age, to estimate the risk (measurable or predictable chance of loss, injury or death) to which a patient is subject before receiving some health care intervention. This adjustment allows comparison of performance and quality across organizations, practitioners, and communities. (from JCAHO, Lexikon, 1994)	Case-Mix Adjustment,Adjustment, Case-Mix,Adjustment, Risk,Adjustments, Case-Mix,Adjustments, Risk,Case Mix Adjustment,Case-Mix Adjustments,Risk Adjustments