Leo Van Der Kamp

Quality of life after myocardial infarction: Translation and validation of the MacNew Questionnaire for a Dutch population

A wide range of instruments have been used in health-related quality of life (HRQL) assessment of patients with coronary artery disease. The MacNew heart disease health-related quality of life questionnaire (MacNew) is a disease-specific measure of HRQL, that has been found to have both good discriminative and evaluative properties. The objective of the present study was to translate the MacNew for a Dutch population, and assess its reliability and validity. Three hundred and thirty-nine cardiac patients, admitted to the hospital after a cardiac event, participated in the study. Questionnaires were filled out at baseline, at 3 months, and at 12 months. A clinically relevant three-factor solution, reflecting an emotional, physical, and social domain of HRQL, allowed us to explain 55% of variance. Angina pectoris was consistently found to be significantly associated with worse HRQL. The pattern of correlations between the subscales of the MacNew on the one hand, and between the subscales of the MacNew and two other, related questionnaires on the other hand, indicated only modest convergent and discriminant validity. The internal consistency was found to be fair to (very) good (ranging between 0.78 and 0.95). Finally, the Dutch MacNew was demonstrated to be substantially more responsive than two other instruments measuring physical and psychological well-being.

Statistical Test Theory for the Behavioral Sciences

PREFACE Measurement and Scaling Definition of a test Measurement and scaling Classical Test Theory True score and measurement error The population of persons Classical Test Theory and Reliability The definition of reliability and the standard error of measurement The definition of parallel tests Reliability and test length Reliability and group homogeneity Estimating the true score Correction for attenuation Estimating Reliability Reliability estimation from a single administration of a test Reliability estimation with parallel tests Reliability estimation with the test-retest method Reliability and factor analysis Score profiles and estimation of true scores Reliability and conditional errors of measurement Generalizability Theory Basic concepts of G theory One-facet designs, the p x i design, and the i : p design The two-facet crossed p x i x j design An example of a two-facet crossed p x i x j design: The generalizability of job performance measurements The two-facet nested p x (i : j) design Other two-facet designs Fixed facets Kinds of measurement errors Conditional error variance Concluding remarks Models for Dichotomous Items The binomial model The generalized binomial model The generalized binomial model and item response models Item analysis and item selection Validity and Validation of Tests Validity and its sources of evidence Selection effects in validation studies Validity and classification Selection and classification with more than one predictor Convergent and discriminant validation: A strategy for evidence-based validity Validation and IRT Research validity: Validity in empirical behavioral research Principal Component Analysis, Factor Analysis, and Structural Equation Modeling: A Very Brief Introduction Principal component analysis (PCA) Exploratory factor analysis Confirmatory factor analysis and structural equation modeling Item Response Models Basic concepts The multivariate normal distribution and polytomous items Item-test regression and item response models Estimation of item parameters Joint maximum likelihood estimation for item and person parameters Joint maximum likelihood estimation and the Rasch model Marginal maximum likelihood estimation Markov chain Monte Carlo Conditional maximum likelihood estimation in the Rasch model More on the estimation of item parameters Maximum likelihood estimation of person parameters Bayesian estimation of person parameters Test and item information Model-data fit Appendix: Maximum likelihood estimation of theta in the Rasch model Applications of Item Response Theory Item analysis and test construction Test construction and test development Item bias or DIF Deviant answer patterns Computerized adaptive testing (CAT) IRT and the measurement of change Concluding remarks Test Equating Some basic data collection designs for equating studies The equipercentile method Linear equating Linear equating with an anchor test A synthesis of observed score equating approaches: The Kernel method IRT models for equating Concluding remarks Answers References Index Each chapter contains an Introduction and Exercises.

How goal disturbance, coping and chest pain relate to quality of life: A study among patients waiting for PTCA.

This article describes psychological correlates of quality of life (QOL) in patients on a waiting list for percutaneous transluminal coronary angioplasty (PTCA). Variables were selected based on a theoretical model describing psychological correlates of QOL in PTCA patients. This model was based on self-regulation and stress-coping theories. The variables in the model are stress appraisal, coping, coping resources, and general and disease-specific QOL variables. Respondents were 122 patients on a 3-month waiting list for a PTCA. Results indicated that PTCA patients had a poorer QOL than matched healthy controls. Using a path analysis approach to regression analysis, it appeared that goal disturbance, avoidant coping, approach coping, and chest pain were related to QOL. More specifically, chest pain and goal disturbance were only related to health-related QOL and negative affect. Both approach and avoidant coping were related to QOL variables. Results could be explained adequately using self-regulation theory. Recommendations for future research and for form and content of rehabilitation programmes were made.

Modeling predictors of quality of life after coronary angioplasty.

Psychological predictors of quality of life in patients undergoing coronary angioplasty were investigated using a prospective model based on self-regulation and stress-coping theories. Predictors (chest pain, disturbance of personal goals, stress perception, approach coping, avoidant coping, and optimism) and three quality of life indicators (disease-specific quality of life, positive affect, and negative affect) were measured with questionnaires in 158 patients both when they were admitted on the waiting list for angioplasty and 3 months after angioplasty. The results were congruent with expectations based on the theories and indicated that the models predicting disease-specific quality of life and negative affect fit the data well. Avoidant Coping and Stress Perception predicted all quality of life indicators. Goal Disturbance predicted only negative quality of life variables, and Approach Coping predicted only positive quality of life variables. Chest Pain predicted Disease-Specific Quality of Life and Positive Affect. Optimism served as a coping resource. Individualized behavior modification interventions were recommended, but the data suggest that patients may not be easily persuaded to engage in health behavior.

Linear Versus Nonlinear Analysis in the Measurement of Effects in a Quasi-Experimental Design

In this study, a two-step procedure for the analysis of pretest-posttest data is developed and illustrated. In the first step, a nonlinear canonical correlation analysis was conducted on data from a pretest-posttest control group design. This technique transforms the measure of the pretests (including the scores on the treatment variable) and the posttests in such a way that they become interrelated linearly and possible deviations from the linear model due to nonlinearity have been minimized. In the second step, the resulting optimally scaled set of pretest and posttest measures were analyzed using covariance procedures to assess program effects. The resultant variance appeared to be increased substantially, either by a better prediction of posttest scores from pretest scores, by a better estimation of the effect of the treatment, or by both. It is concluded that the two-step procedure indeed has important advantages.