Question

Consider a group of 10,000 50 year-old patients with HIV. HIV can lead to AIDS and death. Each year, patients with HIV have a 90% chance of staying in that state, a 7% chance of contracting AIDS, and a 3% chance of dying. Furthermore, patients diagnosed with AIDS have a 60% chance of staying in the AIDS state and a 40% chance of dying each year. Death is thus an "absorbing state", which once entered, cannot be left. The expected utility value for patients living with HIV is 0.8, 0.4 for living with AIDS, and 0 for death. A) Create a decision tree showing the possible outcomes at the end of the first and second years for the 10,000 patients who begin year 1 with HIV. At the end of years 1 and 2, how many patients will still have HIV? How many will have AIDS? How many will have died? B) What is the expected number of QALYs an individual who begins year 1 with HIV can expect to enjoy at the end of year 2? C) In the 10th year, how many patients do you estimate will be in each state? What is the expected number of QALYs per patient at the end of 10 years? How many life years per patient? D) Assume that, regardless of whether or not the individual is currently living with HIV or AIDS, all remaining survivors will die at the end of year 20. What is the life expectancy and quality-adjusted life expectancy for a patient who begins with HIV.

Answer 1