Browsing by Author "Valdivieso, Vicente"

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    Declaración de la Academia Chilena de Medicina sobre el Título V de la Ley 20.850 (Ley Ricarte Soto) y su proyecto de reglamento "De los ensayos clínicos de productos farmacéuticos y elementos de uso médico"
    (Sociedad Chilena de Infectología, 2017) López, Gloria; Valdés, Gloria; Roessler, Emilio; Valdivieso, Vicente
    In Chile, high cost treatments required by selected medical conditions are financed by the State, according to Law 20.850. A bylaw under discussion by the Senate regulates clinical trials, posing complex issues that will endanger local interest in front-line research: 1) The exclusive and mandatory control bestowed to the Institute of Public Health during all stages of the trials and also the surveillance of institutions performing clinical trials, overriding their Clinical Research Review Boards; 2) The 10 year period during which any adverse event is assumed to have been caused by the medication or devise evaluated by the trial, unless the contrary is proven in a judicial process; 3) Individuals submitted to the trials are entitled to free post trial access to the treatment received during the study, financed by the trial supporting entities and as long as the drug or devise is considered to be useful. While agreeing with the need to have a National Registry of Clinical Trials, we predict that the mentioned critical issues in the bylaw will lead to difficulties and unnecessary judicial processes, thus limiting clinicians' interest in performing research. We propose to modify the bylaw, excluding responsibilities on events associated with the natural evolution of the medical condition, with patients' ageing or with comorbidities and clinical events considered unpredictable when the protocol was accepted. We recommend that the free post trial access should be a joint decision involving the patient and the attending physician, taking in consideration that the volunteer has been exposed to risks and burdens, or when discontinuation of treatment entails a vital risk until the treatment under study has been approved and becomes available in the national market.
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    Declaración de la Academia Chilena de Medicina sobre el Título V de la Ley 20.850 (Ley Ricarte Soto) y su proyecto de reglamento “De los ensayos clínicos de productos farmacéuticos y elementos de uso médico”.
    (Sociedad Chilena de Infectología, 2017) López, Gloria; Valdés, Gloria; Roessler, Emilio; Valdivieso, Vicente
    In Chile, high cost treatments required by selected medical conditions are financed by the State, according to Law 20.850. A bylaw under discussion by the Senate regulates clinical trials, posing complex issues that will endanger local interest in front-line research: 1) The exclusive and mandatory control bestowed to the Institute of Public Health during all stages of the trials and also the surveillance of institutions performing clinical trials, overriding their Clinical Research Review Boards; 2) The 10 year period during which any adverse event is assumed to have been caused by the medication or devise evaluated by the trial, unless the contrary is proven in a judicial process; 3) Individuals submitted to the trials are entitled to free post trial access to the treatment received during the study, financed by the trial supporting entities and as long as the drug or devise is considered to be useful. While agreeing with the need to have a National Registry of Clinical Trials, we predict that the mentioned critical issues in the bylaw will lead to difficulties and unnecessary judicial processes, thus limiting clinicians’ interest in performing research. We propose to modify the bylaw, excluding responsibilities on events associated with the natural evolution of the medical condition, with patients’ ageing or with comorbidities and clinical events considered unpredictable when the protocol was accepted. We recommend that the free post trial access should be a joint decision involving the patient and the attending physician, taking in consideration that the volunteer has been exposed to risks and burdens, or when discontinuation of treatment entails a vital risk until the treatment under study has been approved and becomes available in the national market.
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    Factors affecting bus service quality: The case of Santiago, Chile
    (Taylor & Francis, 2019) Valdivieso, Vicente; González, Felipe; de Grange, Luis; Troncoso, Rodrigo
    An econometric analysis is conducted to quantify the impact of different variables on the service quality of the Santiago, Chile bus system. The indicators tested as measures of service quality are the average bus speed, the bus trip time coefficient of variation and the bus headway coefficient of variation. The analysis uses peak hour data obtained for all the routes served by the system’s various concessionaire operators. A separate multiple linear regression model is estimated for each indicator, with the latter as the explained variable. The main explanatory variables are a series of design factors representing different types of dedicated route infrastructure (bus rights-of-way, segregated corridors, bus-only lanes) and the incorporation in some routes of segments of urban motorway. Also included are a number of control variables to capture the effects of demand (number of bus stops,passenger boardings) and the congestion levels at different points along the routes. The results of the models show that the existence of dedicated bus route infrastructure positively impacts all three service quality indicators. The use of motorway segments in particular has a major positive effect on average speed. The model estimates also reveal that the main explanatory factor in headway variability at the end of a route is the headway variability at the start of it, the latter factor determined by operator management decisions regarding bus despatches.
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    Impact of the dedicated infrastructure on bus service quality: an empirical analysis
    (2019) González, Felipe; Valdivieso, Vicente; Grange, Louis de; Troncoso, Rodrigo
    An econometric analysis is conducted to quantify the impact of different variables on the service quality of the Santiago, Chile bus system. The indicators tested as measures of service quality are the average bus speed, the bus trip time coefficient of variation and the bus headway coefficient of variation. The analysis uses peak hour data obtained for all the routes served by the system’s various concessionaire operators. A separate multiple linear regression model is estimated for each indicator, with the latter as the explained variable. The main explanatory variables are a series of design factors representing different types of dedicated route infrastructure and the incorporation in some routes of segments of urban motorway. The results of the models show that the existence of dedicated bus route infrastructure positively impacts all three service quality indicators. The use of motorway segments in particular has a major positive effect on average speed. The model estimates also reveal that the main explanatory factor in headway variability at the end of a route is the headway variability at the start of it, the latter factor determined by operator management decisions regarding bus despatches.

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