Part 1The table below presents the results of study about a screening test for a genetic disorder in a sample of 3600 high-risk children aged 10.This genetic disorder is present from birth.As you can notice this test is not perfectly accurate. No additional test exists to have information about the presence of the disease during the asymptomatic period.Have the diseaseDo not have the diseasePositive screening test1000600Negative screening test2001800When symptoms occur, the disease is too advanced to enable any recovery and patients’ life expectancy is then very limited. If the high-risk population undergoes the screening test. •A screening test costs 1,000€.•If it is positive, patients are systematically treated. •When this disorder is treated during its asymptomatic period, the cure probability is 80%•Treatment costs 100,000€. Answer the following questions:
1.Use the information above to build a decision tree model on an excel file describing the alternative trajectories when the high-risk population takes a screening test vs. when they do not.
2.Compute the probabilities of the events described in the decision tree model based on the information presented in the table above. Then add them onto your diagram.
3.Compute the probability of each trajectory and comment on it.
4.Compute the prevalence of the disease at the end of the modelling for each strategy.
5.Compute the expected cost of no screening and screening strategies and comment on it.
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Part 2 You are askedto simulate the evolution a hypothetical cohort of 10,000 children population aged 10 and high risk for a genetic disorder for 35 years in order to do a CEA of the screening strategy vs. no screening. The below parameters describe this population:VariablesEstimates Prevalence if no screening0,33 (Cf Part 1)Prevalence if screening0,11 (Cf Part 1)Annual mortality rate once symptomatic0,99Annual mortality rate otherwise0,1Annualprobability of becoming symptomatic0,1Annualcost of palliative treatmentwhen symptomatic30 000 Utility score for symptomatic patients0,3Utility score otherwise0,92Here is the Markov diagram to describe the evolution of the children population aged 10 and high risk for a genetic disorder.
1.Compute the annual probabilities of death from the table above.
2.The transition matrix is the same for both strategies. Computeitfrom the table above.
3.For each strategy, compute the Markov trace describing the evolution of the 10,000-childrenfor 35 years with year-cycles. Hint: the difference between no screening and screening strategies is only the prevalence due to the treatment provided in case of screening.
4.For each strategy, draw a figure describing their evolutionfrom their respective Markov trace.Comment on them.
5.Compute total discounted costs and QALYthanks to the Markov traces.Hint: do not forget to add the costs of the screening programcomputed from the decision tree.
6.Provide resource recommendation regarding the intervention vs. no intervention using ICER. Hint: the willingness to pay of the decision makeris 100 000€/QALY.
