1. EXPECTED OUTCOMES The study will provide information on the impact of tobacco use on health from epidemiological, social and economic perspectives in relation to the costs incurred in all health sub-sectors, for the diseases and conditions related to the smoking habit. The results will be presented as consequences of smoking on: Mortality, Disability-adjusted life years (DALYs), Quality-adjusted life years (QALYs), Number of events and Total costs. The data produced will serve to hasten the implementation of programs and effective policies for monitoring and reducing tobacco use. They will also serve as input for other researchers in Argentina to objectively assess the impact and the potential health and economic benefits of the measures that promote a reduction of smoking. These results can be essential strategic inputs in convincing the politicians and decision-makers in Argentina to finally ratify the FCTC. Development and Validation of a Microsimulation Economic Model to Evaluate the Disease Burden Associated with Smoking in Argentina: Phase II, Extravascular Pathology and Extrapulmonary Tumors Andres Pichon-Riviere MD MSc – Institute for Clinical Effectiveness and Health Policy (IECS – Argentina) OBJECTIVE The aim of this project is to provide relevant data on the disease burden associated with smoking in Argentina, including effects on health and economic impact. BACKGROUND Tobacco control policies have been poor in our region. A contributing factor is the lack of local research on the health and economic consequences of tobacco, and an inappropriate belief of policy makers that tobacco control interventions are less urgent than action on other diseases. Although international evidence about disease burden of tobacco is extensive, it is well known that health economic studies results are not directly transferable from one country to another. There is still a need to more precisely understand the disease burden associated with tobacco measured in terms of clinical consequences (illnesses related to smoking), in years and quality of life as well as economic aspects to inform more efficiently tobacco control policies. The origin of this project is a multi-country collaboration among seven countries in Latin America with the aim of explore each country’s context (decision maker’s attitudes, availability and quality of epidemiological data) in order to select the most suitable methodological framework and elaborate a common health economic evaluation model to be applied in the participant countries as well as in other settings where information is scarce (Research Grants from INCLEN Trust and IC-Health). PRELIMINARY RESULTS Calibration of the model was done by comparing model results with key parameters extracted from Argentina’s vital statistics. Validation was performed with 25 cohorts simulations of 50,000 subjects in each age category (40, 50, 60 and 70 years). In figure 1 and 2 we schematically show the model validation process. Validation showed an excellent external validity (+/-5% of predicted values). Table 1 and Graphic 1 show the main results. Table 1. Model Validation: Predicted vs Expected (Local vital statistics) death rates ParameterNumber of cohort simulations (number of subjects in each cohort) Mortality predicted (per 10,000 person year) MEAN Mean difference between predicted and expected (according to National Vital Statistics) CI95% MI mortality 100 (50,000)13.3+ 0.09%-5.0% a +5.1% Lung Cancer Mortality 100 (50,000))10.5+2.1%-3.1% a +7.2% Non-ischemic cardiovascular disease mortality 100 (50,000)27.4-2.0%-5.1% a +1.0% Cerebrovascular disease mortality 100 (50,000)13.0-1.9%-5.4% a +1.6% Mortality for all other causes 100 (50,000)114.1-1.1%-2.4% a +0.1% Graphic 1. Model Validation: Mean differences between Predicted and Expected death rates. Mean differences are expressed as percentage over expected rates. METHODS (cont.) The main advantages were the possibility of having memory of each subject’s history (as opposed to the “memorylessness” of Markov models); incorporating the possibility of simultaneously experiencing different health states during follow-up (which would render a Markov model nearly unmanageable); and being intrinsically probabilistic. A spreadsheet-based model using Microsoft Excel® was programmed using Visual Basic based Macro functions in order to simulate individual subjects’ experiences. The original model calculates the rate of occurrence of five medical conditions: coronary heart disease (myocardial infarction and unstable angina), non- ischemic cardiovascular disease, cerebrovascular disease, chronic obstructive pulmonary disease and lung cancer. As part of this project we are working to extend this original model in order to include extravascular pathology and extrapulmonary tumors. To populate the model it was necessary to obtain the absolute risk of occurrence of events for the non- smoking subpopulation. Once the baseline risk is derived, the absolute risk for smokers and former smokers could be determined, using the known relative risks. Absolute risks in non-smokers were estimated using local vital statistical data and epidemiological data, and using international figures when data were not available (Formula 1). For the estimation of the probability of a diagnosis of cancer conditions, once the absolute risk of death in the non smokers' population was obtained from the previous formula, this information was utilized to estimate the probability of a diagnosis of lung cancer (Formula 2) METHODS After performing a systematic review of existing health economic models of tobacco we decided to build a microsimulation based model. This model incorporates the natural history, costs and quality of life of the most important tobacco-related diseases. Contact: Andres Pichon-Riviere MD MSc, apichon@iecs.org.ar - Institute for Clinical Efectiveness and Health Policy (IECS – Argentina), www.iecs.org.arapichon@iecs.org.ar