1Universidade Estadual de Campinas, Instituto de Matemática Estatí stica e Computação Científica, Departamento de Estatística, Campinas, Brasil. Professor. Email: rtovar34@hotmail.com
2Universidade de São Paulo, Faculdade de Saúde, Departamento de Medicina Social FMRP, Riberão Preto, Brasil. Professor. Email: achacar@fmrp.usp.br
In many practical situations, clinical diagnostic procedures include two or more biological traits whose outcomes are expressed on a continuous scale and are then dichotomized using a cut point. As measurements are performed on the same individual there is a likely correlation between the continuous underlying traits that can go unnoticed when the parameter estimation is done with the resulting binary variables. In this paper, we compare the performance of two different indexes developed to evaluate the dependence between diagnostic clinical tests that assume binary structure in the results with the performance of the binary covariance and two copula dependence parameters.
Key words: Copula, Farlie Gumbel Morgenstern distribution, Gumbel distribution.
Muchos procedimientos de diagnóstico clínico médico exigen la evaluación de dos o mas rasgos biológicos que se ven alterados ante la presencia de fenómenos de enfermedad o infección, los cuales se expresan en una escala contínua de medición con posterior dicotomización usando de un valor límite o punto de corte. Dado que las mediciones son realizadas en el mismo indivíduo, los resultados probablemente presenten dependencia de algún tipo, lo cual puede ser ignorado en la etapa de análisis de datos dada la presentación binaria de los datos. En este estudio comparamos el comportamiento de dos parámetros de dependencia presentes en funciones de cópula con el de la covarianza binaria y dos índices creados para medir dependencia entre pruebas diagnósticas de respuesta dicótoma.
Palabras clave: cópula, distribución Farlie, Gumbel.
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References
]]>1. Bohning, D. & Patilea, V. (2008), 'A capture-recapture approach for screening using two diagnostic tests with availability of disease status for the positives only', Journal of the American Statistical Association 103, 212-221. [ Links ]
2. Dendukuri, N. & Joseph, L. (2001), 'Bayesian approaches to modelling the conditional dependence between multiple diagnostic tests', Biometrics 57, 158-167. [ Links ]
3. Enoe, C., Georgiadis, M. P. & Johnson, W. O. (2000), 'Estimation of sensitivity and specificity of two diagnostic tests', Preventive Veterinary Medicine 45, 61-81. [ Links ]
4. Georgiadis, M. P., Johnson, W. O. & Gardner, I. A. (2003), 'Correlation adjusted estimation of sensitivity and specificity of two diagnostic tests', Journal of the Royal Statistical Society: Series C (Applied Statistics) 52, 63-76. [ Links ]
5. Gumbel, E. J. (1960), 'Bivariate exponential distributions', Journal of the American Statistical Association 55, 698-707. [ Links ]
]]>6. Joseph, L., Gyorkos, T. W. & Coupal, L. (1995), 'Bayesian estimation of disease prevalence and the parameters of diagnostic tests in the absence of a gold standard', American Journal of Epidemiology 141, 263-272. [ Links ]
7. Nelsen, R. B. (1999), An Introduction to Copulas, Springer Verlag, New York. [ Links ]
8. Park, C. G., Park, T. & Shin, D. W. (1996), 'A simple method for generating correlated binary variates', The American Statistician 50(4), 306-310. [ Links ]
9. Shurtleff], D.(1974) Some characteristics related to the incidence of cardiovascular disease and death: 18-year follow-up'An Epidemiological Investigation of Cardiovascular Disease. The Framinham Study' Washington D. C. [ Links ]
10. Thibodeau, L. A. (1981), 'Evaluating diagnostic tests', Biometrics 37, 801-804. [ Links ]
]]>11. Torrance-Rynard, V. L. & Walter, S. D. (1997), 'Effects of dependent errors in the assessment of diagnostic tests performance', Statistics in Medicine 16, 2157-2175. [ Links ]
12. Vacek, P. M. (1985), 'The effect of conditional dependence on the evaluation of diagnostic tests', Biometrics 41, 959-968. [ Links ]
Este artículo se puede citar en LaTeX utilizando la siguiente referencia bibliográfica de BibTeX:
@ARTICLE{RCEv34n3a03,
AUTHOR = {Tovar, José Rafael and Achcar, Jorge Alberto},
TITLE = {{Indexes to Measure Dependence between Clinical Diagnostic Tests: A Comparative Study}},
JOURNAL = {Revista Colombiana de Estadística},
YEAR = {2011}, ]]>
volume = {34},
number = {3},
pages = {433-450}
}