La importancia del diagnóstico temprano en la supervivencia de los pacientes HIV positivos
Date
2010
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Abstract
En la Argentina, el diagnóstico del HIV se realiza por solicitud voluntaria de los individuos o a través de la detección de sintomatología asociada a la infección. Sin embargo, debido a la elevada proporción de sujetos portadores que desconocen su estado serológico son necesarias nuevas estrategias. En el presente artículo mostramos cómo un modelo matemático predice el impacto de la expansión de la prueba diagnóstica del HIV en la Argentina. El modelo se basa en matrices de Markov y utiliza probabilidades de transición dependientes de parámetros obtenidos de estudios de cohortes nacionales e internacionales. Las predicciones incluyen tiempo en estadios clínicos y tratamiento, conteo de CD4, carga viral, estadío de infección, edad, tasas de mortalidad y proporción de infección desconocida a nivel poblacional. Las simulaciones se desarrollaron para la situación actual y para un escenario hipotético con diagnóstico más temprano. Mostramos predicciones que sugieren que el diagnóstico realizado antes de la progresión a sida incrementaría la expectativa de vida en unos 10.7 años. También, mostramos cómo la reducción del tiempo al diagnóstico hasta 5 años o menos desde la infección reduciría la tasa de mortalidad en el primer año de HAART de 7.6% a 2.1%, la proporción de infección no reconocida de 43.2% a 23.8% y la proporción de individuos con infección desconocida y que requieren tratamiento de 12% a 0.2%. Basados en estas predicciones resaltamos la importancia de implementar políticas de salud destinadas a detectar la infección por HIV en estadios tempranos en la Argentina.
In Argentina, HIV diagnosis is reached by voluntary testing or symptom-based case findings. However, because of the high proportion of infected individuals unaware of their serologic status new strategies are required. In this article we show how a mathematic model predicts the impact of expanding HIV testing in Argentina. The model is based on time-dependent Markov matrixes and applies parameters-dependent transition-probabilities obtained from both national and international cohort studies. Outputs include time on clinical stages and therapy regime, CD4-count, viral-load, infection-state and age; mortality rates and proportion of unidentified infection at a population-level. Simulations were performed for current testing strategy and for a theoretical scenario with earlier diagnosis. We show how our prediction suggests that diagnosis before onset of symptoms would increase life expectancy by 10.7 years. Also, we show how a reduction of time to diagnosis to 5 or less years from infection would reduce mortality rates in the first year of HAART from 7.6% to 2.1%, the proportion of unrecognized infection from 43.2% to 23.8% and the proportion of individuals with unaware infection needing treatment from 12% to 0.2%. Based on this prediction we stress the importance of implementing health policies aimed at detecting HIV infection in early stages in Argentina.
In Argentina, HIV diagnosis is reached by voluntary testing or symptom-based case findings. However, because of the high proportion of infected individuals unaware of their serologic status new strategies are required. In this article we show how a mathematic model predicts the impact of expanding HIV testing in Argentina. The model is based on time-dependent Markov matrixes and applies parameters-dependent transition-probabilities obtained from both national and international cohort studies. Outputs include time on clinical stages and therapy regime, CD4-count, viral-load, infection-state and age; mortality rates and proportion of unidentified infection at a population-level. Simulations were performed for current testing strategy and for a theoretical scenario with earlier diagnosis. We show how our prediction suggests that diagnosis before onset of symptoms would increase life expectancy by 10.7 years. Also, we show how a reduction of time to diagnosis to 5 or less years from infection would reduce mortality rates in the first year of HAART from 7.6% to 2.1%, the proportion of unrecognized infection from 43.2% to 23.8% and the proportion of individuals with unaware infection needing treatment from 12% to 0.2%. Based on this prediction we stress the importance of implementing health policies aimed at detecting HIV infection in early stages in Argentina.
Description
Keywords
Diagnóstico temprano, supervivencia, pacientes HIV positivos, Importancia
Citation
Dilernia, D. A., Mónaco, D. C., Krolewiecki, A. J., et al. [The importance of early diagnosis for the survival of HIV positive patients]. Medicina, 70(5), 453-456. PMID: 20920966.