Exam 5: Epidemiology, Biostatistics, and Medical Informatics

A new research is being done to compare the effectiveness of intravenous immunoglobulin vs analgesics in the treatment of pain in individuals with idiopathic small fiber neuropathy. A total of 100 eligible patients who met the inclusion/exclusion criteria are randomly allocated to one of two groups by a computer. Which of the following is the most likely outcome of this study's approach of allocating patients to treatment groups?

A big prospective research is looking into the link between alcohol intake and breast cancer. Through a random selection of residence locations, 4000 middle-aged women are included in the research. Periodic surveys are used to examine daily alcohol intake and breast cancer incidence. The authors report a relative risk of 1.32 (95 percent confidence range = 0.90-1.85) for alcohol intake and breast cancer after a five-year follow-up; 800 participants were lost to follow-up at the conclusion of the research, the majority of whom were moderate to heavy alcohol drinkers. Which of the following biases is most likely to be present and may have influenced the results, based on this information?

A new trial on a novel test for identifying acute myocardial infarction (AMI) has been begun. The test's sensitivity is assessed to be 75% and its specificity to be 80%. The research includes 600 patients, 200 of whom are AMI instances as established by the diagnostic gold standard. How many false negatives may be anticipated in the study?

A meta-analysis of multiple trials on the effect of cocoa consumption on systolic blood pressure (SBP) yielded the following findings: All of the trials looked at the change in SBP after two weeks. Which of the following is the most appropriate conclusion based on the data?

Family members of an 89-year-old man bring him to a geriatric clinic because they are afraid that he is acquiring dementia owing to recent memory deterioration. The attending physician employs a new cognitive test (test X) to help rule out dementia. The test result for the patient is negative. A research examining the efficacy of test X in a sample of 200 adults aged >85, where dementia prevalence is 50%, found that the test had a specificity of 80% and a sensitivity of 90%. What is the likelihood that this patient does not have dementia if his or her pretest probability of having dementia is equal to the disease prevalence in the study population?

In a reference sample of hundreds of healthy subjects, the laboratory reference range for a novel marker of cardiac injury is 0.04-0.08 U/mL at the standard 95% level of probability.  The marker has very high sensitivity and specificity for myocardial tissue.  The clinical cardiology team would like to use a 99.7% reference range to assess patients who come to the emergency department with chest pain and have a high pretest probability of cardiac ischemia.  An elevated value of the marker is defined as exceeding the 99.7th percentile of the reference sample.  Assuming a normal (Gaussian) distribution with a mean of 0.06 U/mL, which of the following most closely approximates the corresponding reference range?

A novel test for detecting urinary tract infections in women is being tested. Positive urine dipstick plus urine culture is the gold standard for comparison. The study's findings are presented below.  What is the specificity of the new test?

A team of psychiatrists undertakes a double-blind, placebo-controlled randomized study to assess the effectiveness and safety of cariprazine for the treatment of depressive episodes associated with bipolar I disorder (bipolar depression) in adults. The treatment response rate for cariprazine was 46% against 32% for placebo, while the rate for all adverse events was 7% for cariprazine versus 5% for placebo. The rate differences were statistically significant. Which of the following is the estimated number of patients who must be exposed to cariprazine in order to injure 1 person who would not have been harmed otherwise?

A randomized controlled study was done to evaluate the efficacy of a novel medication in reducing severe cutaneous responses in individuals with rheumatoid arthritis treated with adalimumab. 75 persons with rheumatoid arthritis were given the new medicine in addition to adalimumab, whereas the other 75 got a placebo in addition to adalimumab. According to the findings, six individuals in the new treatment group experienced severe cutaneous responses, compared to nine in the placebo group. Which of the following best describes the new medication group's relative risk decrease for severe cutaneous reactions?

In a group of 1,000 75-year-old women, a test is utilized to identify dementia. The test has an 80 percent sensitivity and a 90 percent specificity. The test is then utilized as a diagnostic tool in two different groups of women of the same age: population 1 has a dementia prevalence of 15%, and population 2 has a dementia prevalence of 30%. Which of the following best illustrates the relationship between the negative predictive values (NPV) and positive predictive values (PPV) from populations 1 and 2?

Zeracizumab is an investigational angiogenesis inhibitor that targets vascular endothelial growth factor and is being evaluated for the treatment of advanced non-squamous non-small cell lung cancer that has not responded to chemotherapy (NSCLC). To establish the clinical effectiveness of the experimental treatment, the pharma firm analyzes 1-year survival following treatment as part of the review procedure. The outcomes are shown in the table below.   Which of the following best describes the zeracizumab-containing regimen's number needed to harm?

Left atrial pressure may be estimated using pulmonary capillary wedge pressure (PCWP) measurements; the typical range is 6-12 mm Hg, and recorded values are whole numbers. Over the course of two hours, a patient in the critical care unit has 20 serial PCWP measures collected. The maximum recorded value among these 20 observations is 12 mm Hg, while the minimum recorded value is 10 mm Hg. Which of the following is most likely to remain unaltered if the next measurement is 26 mm Hg?

The findings of a recent research on the relationship between glycosylated hemoglobin (HbA1c) levels and high-sensitivity C-reactive protein (hs-CRP) levels in individuals with type II diabetes mellitus (T2DM) are as follows: "Our findings suggest that HbA1c levels are favorably linked with hs-CRP levels (r = 0.80). The likelihood that these results were due to chance alone is 3%, with a 10% possibility of concluding that there is no association between HbA1c and hs-CRP when omitted "e does exist." Based on this data, which of the following is the most likely p-value and power of the correlation test in the study?

The population pyramid of a certain country is shown below. Based on the diagram, which of the following best characterizes this population?