A new anti-epileptic drug is being tested for adolescents with absence seizures. The control group consists of 300 adolescents while 200 adolescents are given the new drug. After 6 months, 80 adolescents in the control group had a seizure while only 10 adolescents in the group taking the new medication had a seizure. What is the relative risk reduction?
What is the term for a drug that has its own effects but doesn’t treat the condition it is prescribed for?
A 42-year-old male has recently been diagnosed with prostate cancer and is considering a new chemotherapeutic agent that is currently in a trial phase. However, there are concerns that the drug may increase the risk of developing thrombocytopenia. The patient wants to know his risk of developing thrombocytopenia if he decides to take this new drug.
In a randomized study of age and sex-matched prostate cancer patients, 245 patients out of 800 patients who were taking the new agent did not develop thrombocytopenia. In the 1,500 patients who did not take the new agent, 1,100 developed thrombocytopenia.
What is the relative risk of developing thrombocytopenia following treatment with this new chemotherapeutic agent?
A cohort study is being designed to investigate the association between smoking and breast cancer. What is the typical measure of outcome in a cohort study?
A medical research team conducts a randomized controlled trial to investigate the effect of a new treatment on cognitive decline in elderly patients. Ten participants are randomly assigned to the new treatment, and 10 continue with standard care. The results show no significant difference in cognitive decline between the two groups, with a p-value of 0.18 and an absolute risk reduction of 0.03. However, subsequent research with a larger patient population reveals a significant treatment effect on cognitive decline.
What statistical mistake did the research team likely make?
A medical research team is comparing the existing diagnostic scanning method for breast cancer with a new type of scan. This research has taken place over a number of years. Currently, patients are scanned once symptoms develop and the mean survival time is 2 years from the point of diagnosis. The new scan allows for the detection of breast cancer by screening high-risk patients before symptoms develop. With this new scan, breast cancer is diagnosed 2 years before symptoms develop and overall survival time from diagnosis is 3 years.
What bias is this an example of?
A new blood test is developed to detect pulmonary embolisms (PEs) in elderly patients with covid-19. A study compares its performance with the current gold standard for diagnosis, CT pulmonary angiogram (CTPA) scanning.
A total of 250 elderly patients with covid-19 undergo CTPA scanning. Amongst those, 50 patients are identified as having PEs on CTPA scans and are subsequently tested using the new blood test. Of these, 40 have a positive test, and 10 have a negative test. Of the 200 covid-19 patients who did not have a PE demonstrated on CTPA scanning, 180 have a negative blood test, and 20 have a positive blood test.
What is the sensitivity of the new test based on the given results?
A 42-year-old man is currently waiting for the results of his recent HIV test. The test has a specificity of 99.6%. What can be said about this test?
A new screening tool for lower gastrointestinal malignancies, known as the Faecal Immunochemical Test (FIT), has been developed. The researchers want to determine the effectiveness of the test in detecting colorectal cancer in individuals aged 50 and above.
To assess the test’s accuracy, the researchers conducted a study where all participants aged 50 and above underwent a FIT and were subsequently followed up with a colonoscopy, which is considered the gold standard test for detecting colorectal cancer.
Out of the 100 participants who tested positive on the initial FIT, 80 were confirmed to have colorectal cancer on colonoscopy. On the other hand, out of the 900 participants who tested negative on the initial FIT, 20 were later found to have colorectal cancer on colonoscopy.
What is the sensitivity of the FIT in detecting colorectal cancer in individuals aged 50 and above?
A study is conducted to evaluate the efficacy of a new auto-antibody test as a screening tool for prostate cancer. The study involves 1000 patients, out of which 70 test positive for the auto-antibody. Among the positive cases, 50 are confirmed to have prostate cancer through biopsy. On the other hand, 10 patients who tested negative for the auto-antibody were later diagnosed with prostate cancer.
What is the percentage of positive predictive value of this test?