Model-Free Time Curves for Longitudinal Data Analysis

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00005457
Recruitment Status : Completed
First Posted : May 26, 2000
Last Update Posted : February 29, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To enhance statistical methods for epidemiological studies by extending the Disturbed Highest Derivative Polynomial (DHDP) to models for binary-logistic and Poisson data and by including random subject effects in the Gaussian model.

Condition or disease
Cardiovascular Diseases Heart Diseases

Detailed Description:


In previous work the investigator had developed the Disturbed Highest Derivative Polynomial (DHDP) as a model-free time curve and had published the theoretical development for its use as the overall time curve in a linear Gaussian model for longitudinal data with fixed covariate effects and autocorrelated errors but without subject effects. For the logistic model, the DHDP would replace the constant which appeared in the log odds in the non-longitudinal case. The first-order DHDP was a straight line whose slope received random disturbances over time. As such, it was capable of fitting a rich variety of arbitrarily changing time curves. The second-order DHDP would generally provide a fit with smaller high frequency variation. There are a number of longitudinal data analysis methods currently available for Gaussian and binary-logistic data. They all have in common the requirement to explicitly model the overall time curve--usually by a low order deterministic polynomial. The main significance of this proposal was to represent the overall time curve by a DHDP, thereby allowing the possibility for fitting arbitrarily changing time curves without explicitly modeling the form of the change over time. The order of the DHDP can be selected by a modification of the Akaike Information Criterion. The Poisson model should be useful in fitting the periodic reported incidence of a rare disease. The relationship of the DHDP to the Smoothing Polynomial Spline (SPS) was shown and methods were developed for using a SPS instead of a DHDP in analysis. Robustness of the methods were examined by computer simulation studies which evaluated and compared the ability of the DHDP and SPS models to estimate covariate effects and time curves when the time curves were generated by processes other than DHDP.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Study Type : Observational
Study Start Date : January 1991
Actual Study Completion Date : June 1994

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
No eligibility criteria

Publications: Identifier: NCT00005457     History of Changes
Other Study ID Numbers: 4901
R01HL039614 ( U.S. NIH Grant/Contract )
First Posted: May 26, 2000    Key Record Dates
Last Update Posted: February 29, 2016
Last Verified: June 2000

Additional relevant MeSH terms:
Cardiovascular Diseases
Heart Diseases