The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Peter C Austin - One of the best experts on this subject based on the ideXlab platform.
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bayesian extensions of the tobit model for analyzing measures of Health Status
Medical Decision Making, 2002Co-Authors: Peter C AustinAbstract:Self-reported Health Status is often measured using utility indices that provide a score intended to summarize an individual’s Health. Measurements of Health Status can be subject to a ceiling effect. Frequently, researchers want to examine relationships between determinants of Health and measures of Health Status. In this article, Bayesian extensions of the classical Tobit model are used to study the relationship between Health Status and predictors of Health. The author examined models where the conditional distribution of Health Status was either normal or lognormal, and allowed for both homoscedasticity and heteroscedasticity. Bayes factors were then used to compare the evidence for a given model against that for a competing model. The author found very strong evidence that the distribution of the Health Utilities Index, conditional on age, gender, income adequacy, and number of chronic conditions, was normal with nonuniform variance, compared to the competing models.
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the use of the tobit model for analyzing measures of Health Status
Quality of Life Research, 2000Co-Authors: Peter C Austin, Michael Escobar, Jacek A KopecAbstract:Self-reported Health Status is often measured using psychometric or utility indices that provide a score intended to summarize an individual's Health. Measurements of Health Status can be subject to a ceiling effect. Frequently, researchers want to examine relationships between determinants of Health and measures of Health Status. Regression methods that ignore the presence of a ceiling effect, or of censoring in the Health Status measurements can produce biased coefficient estimates. The Tobit regression model is a frequently used tool for modeling censored variables in econometrics research. The authors carried out a Monte-Carlo simulation study to contrast the performance of the Tobit model for censored data with that of ordinary least squares (OLS) regression. It was demonstrated that in the presence of a ceiling effect, if the conditional distribution of the measure of Health Status had uniform variance, then the coefficient estimates from the Tobit model have superior performance compared with estimates from OLS regression. However, if the conditional distribution had non-uniform variance, then the Tobit model performed at least as poorly as the OLS model.
P M Brooks - One of the best experts on this subject based on the ideXlab platform.
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patient self efficacy and Health locus of control relationships with Health Status and arthritis related expenditure
Rheumatology, 2006Co-Authors: Marita Cross, Lyn March, Helen Lapsley, E Byrne, P M BrooksAbstract:Objective. To explore the relationship between measures of self-efficacy, Health locus of control, Health Status and direct medical expenditure among community-dwelling subjects with rheumatoid arthritis (RA) and osteoarthritis (OA). Methods. This analysis is part of a larger ongoing study of the costs and outcomes of arthritis and its treatments. Community-dwelling RA and OA respondents completed questionnaires concerning arthritis-related expenditure, Health Status, arthritis related self-efficacy and Health locus of control. Results. Data were obtained from 70 RA respondents and 223 OA respondents. The majority of respondents were female with a mean age of 63 yr for RA respondents and 68 yr for OA respondents. Among the RA respondents, those with higher self-efficacy reported better Health Status and lower overall costs. Health locus of control was not consistently correlated with Health Status. OA respondents with higher self-efficacy reported better Health Status and lower costs. Health locus of control had more influence. OA respondents with higher external locus of control reported worse pain and function. A higher belief in chance as a determinant of Health was correlated with more visits to general practitioners and a higher cost to both the respondent and the Health system. Conclusion. Higher self-efficacy, which is amenable to change through education programmes, was associated with better Health Status and lower costs to the respondent and the Health system in this cross-sectional study. Locus of control had less of an influence; however, the tendency was for those with higher external locus of control to have higher costs and worse Health Status. As the measurement of these constructs is simple and the outcome potentially affects Health Status, these results have implications for future intervention studies to improve quality of life and reduce the financial impact of arthritis on both the Health-care system and patients.
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living with rheumatoid arthritis expenditures Health Status and social impact on patients
Annals of the Rheumatic Diseases, 2002Co-Authors: Helen Lapsley, Marita Cross, Lyn March, K Tribe, B G Courtenay, P M BrooksAbstract:OBJECTIVE: To determine costs related to living with rheumatoid arthritis (RA), and to identify the association between Health Status-as measured by the Health Status Questionnaire short form-36 (SF-36) and the disease specific index Health Assessment Questionnaire (HAQ)-and the social impact of RA. METHODS: A prospective cohort study was carried out on 81 patients with RA who completed four consecutive three month cost diaries. The SF-36, HAQ, and social impact at baseline and one year follow up were also assessed. RESULTS: Women reported worse SF-36 physical function and HAQ scores than men and received more assistance from family and friends. Women spent more on non-prescription medication and devices to assist them than men. Older patients had higher expenditure on visits to Health professionals, whereas younger patients spent more on prescription medication and tests. Pension Status and membership of private Health insurance schemes were important determinants in these differences in expenditure. CONCLUSION: Costs increased with duration of disease, those with private Health insurance had greater out of pocket costs (excluding membership fees), and those with pension support had fewer costs. Women were more affected by RA than men in Health Status, social impact, and out of pocket costs.
Gretchen Von Oesen - One of the best experts on this subject based on the ideXlab platform.
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a comparison of patients with late stage rheumatoid arthritis and osteoarthritis of the shoulder using self assessed shoulder function and Health Status
Arthritis Care and Research, 1997Co-Authors: Frederick A Matsen, Kevin L Smith, Susan E Debartolo, Gretchen Von OesenAbstract:Objective. To compare the function and Health Status of individuals with advanced rheumatoid arthritis (RA) and osteoarthritis (OA) of the shoulder using standardized patient self-assessment tools. Methods. A group of patients with late-stage arthritic involvement of the shoulder was evaluated at the time of initial presentation using 2 questionnaires, one focusing on shoulder function and the other on overall Health Status. Results. There was substantial variability in the shoulder function and Health Status within each diagnostic group; however, both groups demonstrated significant deficits in their Simple Shoulder Test responses and in many of their Health Status Questionnaire-Short Form 36 scores. While the patients with RA tended to have somewhat greater impairment of shoulder function, many of the differences were not statistically significant. By contrast, most Health Status parameters were significantly more impaired in the patients with RA. Conclusions. Among patients with late-stage shoulder arthritis, the overall Health Status of those with RA is significantly worse than those with OA. Differences in Health Status may be important in selecting the optimal management for individual patients with latestage shoulder arthritis. Self-assessment questionnaires are effective in characterizing these differences.
Jacek A Kopec - One of the best experts on this subject based on the ideXlab platform.
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the use of the tobit model for analyzing measures of Health Status
Quality of Life Research, 2000Co-Authors: Peter C Austin, Michael Escobar, Jacek A KopecAbstract:Self-reported Health Status is often measured using psychometric or utility indices that provide a score intended to summarize an individual's Health. Measurements of Health Status can be subject to a ceiling effect. Frequently, researchers want to examine relationships between determinants of Health and measures of Health Status. Regression methods that ignore the presence of a ceiling effect, or of censoring in the Health Status measurements can produce biased coefficient estimates. The Tobit regression model is a frequently used tool for modeling censored variables in econometrics research. The authors carried out a Monte-Carlo simulation study to contrast the performance of the Tobit model for censored data with that of ordinary least squares (OLS) regression. It was demonstrated that in the presence of a ceiling effect, if the conditional distribution of the measure of Health Status had uniform variance, then the coefficient estimates from the Tobit model have superior performance compared with estimates from OLS regression. However, if the conditional distribution had non-uniform variance, then the Tobit model performed at least as poorly as the OLS model.
Johan W Groothoff - One of the best experts on this subject based on the ideXlab platform.
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social support as a predictor of perceived Health Status in patients with multiple sclerosis
Patient Education and Counseling, 2008Co-Authors: Martina Krokavcova, Jitse P Van Dijk, Iveta Nagyova, Jaroslav Rosenberger, M Gavelova, Berrie Middel, Zuzana Gdovinova, Johan W GroothoffAbstract:Abstract Objective The main aim of this study was to investigate whether different levels of perceived social support are associated with different levels of perceived Health Status in multiple sclerosis (MS) patients. Methods Two hundred and seven MS patients (38.4 ± 10.6 years, 66.2% female) completed the Short-Form-36 Health Survey (SF-36) as the measure for perceived Health Status, and the perceived social support scale (PSSS) as the measure for social support. Functional disability was assessed using Kurtzke's expanded disability Status scale (EDSS). The contribution of EDSS and PSSS for explaining the variance in SF-36 was investigated with multiple linear regression analysis. Results Demographic variables and EDSS explained 44% of the variance of the physical Health summary scale in the SF-36. Demographic variables, EDSS and PSSS from family and friends explained 24% of the variance in mental Health summary scale in the SF-36. Results varied according to the multiple linear regression analyses of predictors of variance in the eight dimensions of the SF-36. Conclusion PSSS from significant others was positively associated with general Health dimension of perceived physical Health Status, while PSSS from family and friends was positively associated with perceived mental Health Status in MS patients. Practice implications The results show the importance of supporting social ties and relationships between MS patients and others.
