Please answer all parts

Study Design Case Study BACKGROUND A potential client at a pharmaceutical company has reached out to you about a retrospective database analysis that they're considering. The company is preparing to launch a new medication on the market that is indicated for chronic hepatitis C infection (HCV) genotype 1 in adults. Based on results from the clinical trial, the company thinks that the value proposition for their drug is in treating patients who have either failed an earlier treatment regimen or who have discontinued treatment due to adverse effects. Successful treatment is defined as sustained virological response, specifically, the absence of detectable HCV RNA in lab tests in the 3 to 6 months after stopping treatment. Possible adverse events include anemia, gastrointestinal symptoms, fatigue, nausea, pruritus, rash, and insomnia. The client would like to conduct an analysis to understand the profile and treatment patterns of HCV patients who are not achieving treatment goals, as well as the burden of illness. Specifically, they have the following questions: 1. What treatments are HCV genotype 1 patients currently taking? 2. What proportion of patients failed their treatment regimen? What proportion of patients discontinue their treatment? If they discontinue, what is the reason (i.e., lack of on treatment virological response reason (i.e., lack of on treatment virological response or adverse effects)? 3. What is the estimated number of patients in the US population who have been treated with current HCV treatments and not achieved goal? The client thinks a large database analysis is the way to go for answering these questions. They want you to put together a proposal that includes what data source would be used, preliminary sample selection criteria, measures of interest, and statistical analysis. If there are multiple options, they want to hear your thoughts on the tradeoffs between different options. STUDY DESIGN QUESTIONS Based on the above information, please briefly lay out how you would think about preparing the proposal and any recommendations you have for the client. While specific knowledge about the therapeutic area is appreciated, it is not necessary. You can structure your response in any way that you think makes sense. As a general guide, your response should cover the topics/questions below. The goal of this exercise is not to get a \"correct\" answer, but rather for us to understand your thought process. Please use the questions below as guides rather than questions that require a definitive answer in terms of framing your process of thinking through the study. Data Source I] What criteria would you use to decide the best database(s) for addressing the clients question? I] What data source would you recommend and why? I] How many months or years of data would you recommend and why? E.g., use a data cut of the most recent 3 years of data because... Patient Selection Criteria D What would be the study population of interest? If you're not familiar with the therapeutic area, what kind of questions would you ask to help you decide on the study population? D Would you set this up using a single cohort or multiple cohorts? D What would consider for setting the patient identification window (time period in which you'll select your sample), index date, baseline, and follow- up periods. 0 We've provided the following blank patient timeline figure which you can use to indicate the time periods of interest. This figure does not reflect a \"correct\" design that we are looking for, but rather is meant as a general example timeline to help you address the question. Baseline Period Follow-up Period llgl index Date %% lYl Patient identication window Time Periods and Analytic Measures D What would be the index date? D What analytic time periods would be appropriate? D What baseline and follow-up measures would be assessed? How would you define these measures (e.g., What kinds of codes? What algorithms might you want to use or research, if any?) you want to use or research, if any?) Statistical Analysis I] What statistical methods would be used? Limitations I] What are the limitations of your proposed study? This could be related to limitations in any of the study elements that you've presented. If you want to pull references for this exercise, please include citations