Exam 5: Epidemiology, Biostatistics, and Medical Informatics

A team of scientists conducts a study to assess the pharmacologic qualities of oxfendazole, an antihelminthic drug. Healthy volunteers are given escalating oral dosages of oxfendazole (0.5 to 60 mg/kg) as part of the study. Data is gathered to create a pharmacokinetic profile of the medication and its metabolites, and the occurrence of side effects is documented for each dose level. The study includes 20 healthy male and female (nonchildbearing potential) subjects. Oxfendazole has been proven to be well tolerated over the whole dosage range, with no significant side effects or fatalities. Which of the following statements best defines this sort of research?

For the previous 15 years, the prevalence of a chronic condition that primarily affects older people has been stable in a community. Many young healthy people leave the population as a result of worsening economic situations that have no influence on the sickness itself. Which of the following is the most likely effect of emigration on illness prevalence estimates in the coming years?

A research is carried out to describe a country's age-sex distribution. According to official data, the country's population pyramid looks like this. Which of the following statements about this country and its people is most likely correct, according to the population pyramid?

In patients with severe aortic stenosis, a randomized controlled trial is being conducted to compare transcatheter aortic valve replacement (TAVR) with surgical aortic valve replacement using a self-expanding transcatheter aortic valve bioprosthesis. The goal is to calculate the difference in risk of mortality from any cause. Seven hundred forty-seven patients with severe aortic stenosis who are at high surgical risk are recruited and randomly randomized to TAVR or surgical valve replacement groups. Following discharge, there are follow-up examinations at one month, six months, and one year. The following are the 1-year follow-up results:  Which of the following better depicts the absolute risk decrease for mortality from any cause in TAVR patients compared to surgical replacement patients? 

A research is being conducted to assess the effectiveness of KM28, a novel medication. The trial will compare KM28 with standard treatment to standard care alone in terms of lowering the risk of recurrent breast cancer. The FDA will approve the new medicine if KM28 with standard treatment reduces the incidence of breast cancer recurrence by at least 40% when compared to conventional therapy alone. On usual treatment, the recurrence rate is reported to be 8%. What is the maximum incidence of recurrent illness acceptable for women treated with KM28 with conventional treatment in order for the FDA to approve KM28?

A study was carried out to determine the age at menarche in young female gymnasts. Gymnasts were split into two groups based on their devotion to the sport: competitive gymnasts and leisure gymnasts. Assuming that age at menarche is normally distributed, which of the following is closest to the probability that a randomly chosen competitive gymnast will have onset of menarche at age 16 and more?

A placebo-controlled clinical study was done by a research team to see whether a novel medicine for treating acute migraine with or without aura in adults is more effective than usual treatment. In the trial, 3,500 individuals with acute migraine were randomly allocated to either the novel medicine or usual therapy. The researchers opt to set alpha to 0.01 rather than 0.05 during the data analysis phase. Which of the following outcomes is most likely as a result of this change?

A research is being conducted to evaluate the effectiveness of spironolactone in patients with heart failure. For two years, 450 patients are given either spironolactone or a placebo. Neither the patients nor the doctors are aware of who is taking the medicine or the placebo. The above-mentioned study design is most successful in preventing:

A medical student is reviewing the charts of patients who have been hospitalized to the local emergency department with severe pancreatitis. He wants to compare blood glucose levels in moderate and severe instances. He chooses to do a descriptive study of the factors in each group before attempting to compare the mean blood glucose levels between the two groups of patients. The distribution of blood glucose levels in patients with severe acute pancreatitis was found to be strongly positively skewed. Which of the following statements about the data for the severe acute pancreatitis group is most likely correct?

The goal of a prospective cohort study in a group of people with type 2 diabetes mellitus (T2DM) is to look at the relationship between morbid obesity (BMI >40 kg/m²) and the risk of developing diabetic nephropathy. Adults with T2DM, a BMI more than 40 kg/m², and no diabetic nephropathy comprise one of the study's groups. Which of the following comparison groups is best suited for this prospective cohort study?

A group of scientists seeks to find out what causes hospital-acquired bacteremia caused by methicillin-resistant Staphylococcus aureus (MRS A). Following MRSA was identified from a blood sample collected from them on the third or subsequent day after admission, 45 patients were recruited in the research. In addition, 90 individuals admitted to the hospital during the same time period with a duration of stay of more than two days who did not have bacteremia were chosen at random. The frequency of variables such as central line or urine catheter placement and surgical site infection was then compared between the two groups. Which of the following null hypotheses is most relevant for this study?

Researchers are looking at the link between colorectal cancer and the usage of nonsteroidal anti-inflammatory drugs. They interviewed a group of patients with biopsy-proven colorectal cancer, followed by a group of patients' neighbors of comparable age and race. The study is based on comparing the outcomes of two individuals with similar features (one from each of the two groups). Which of the following possible issues with this study is best addressed by this design technique?

A 45-year-old man arrives at the office for a normal check-up. The patient has a first-degree relative who has Alzheimer's disease and is worried about contracting the condition. He read in the papers that a lack of yellow and orange fruits and vegetables has been linked to Alzheimer's disease and wants to know how likely he is to get the condition. A recent cohort research that examined the relationship between blood carotene content and Alzheimer disease was discovered in a medical literature review. A 20-year follow-up study of 200 middle-aged participants having a first-degree relative with Alzheimer dementia was conducted to assess the illness's progression. The outcomes are as follows: Assuming the patient's carotene levels are low, what is his 20-year risk of developing Alzheimer disease?

The population pyramid of all races and ethnicities for a certain state in the United States is shown below. Which of the following statements best describes the population of this specific state?

A researcher wants to see if there is a link between neural tube abnormalities and the usage of acetaminophen during the first three months of pregnancy. He selects a group of women at random who have recently had kids with neural tube abnormalities and a second group of women who have just delivered babies who appear to be healthy. Following that, these two groups were asked about their usage of acetaminophen throughout the first three months of pregnancy. Which of the following association measurements are the investigators most likely to report?

A research lab creates a novel serologic test to identify prostate cancer. To evaluate sensitivity and specificity characteristics, the novel test is compared to transrectal ultrasound-guided prostate biopsy. The test results are reported to be negative in 95 percent of persons who do not have the condition. What is the likelihood of all eight test results being negative if the new assay is performed on eight blood samples collected from people without prostate cancer?

In a big community hospital, plasma homocysteine levels are examined in patients with acute coronary syndrome. The average plasma homocysteine level in this cohort is 11.1 mol/L, with a standard deviation of 1.2 mol/L. The mean plasma level in a different group of patients hospitalized on the general ward at the same hospital is 9.5 mol/L, with a standard deviation of 1.3 mol/L. Which of the following statistical techniques should be used to compare the mean homocysteine levels of these two patient groups?

A research compared the effect of a low-carbohydrate diet on body weight to that of a low-fat diet. A sample of 150 overweight but otherwise healthy people from a big metropolis were enrolled in the trial and randomly allocated in a 1:1 ratio to either the low-carbohydrate (40 g/d) or the low-fat (7 percent saturated fat) diet. At 12 months, the low-carbohydrate diet group lost more weight than the low-fat diet group, with a mean difference in body weight loss of 3.5 kg (p = 0.01, predefined significance threshold = 0.05). Which of the following is the most correct interpretation of the study's findings?

A 65-year-old man arrives to the office because his family is concerned about his persistent cough after smoking. The patient inquires about the possibility of adult smokers having chronic obstructive pulmonary disease (COPD). According to a recent cohort research, the relative risk (RR) of COPD for nonsmokers is 0.10 and for moderate smokers is 0.40 when compared to heavy smokers. The patient is a light smoker. According to the study, which of the following is the relative risk of COPD among moderate smokers vs nonsmokers?

A novel dipstick test for identifying urinary tract infections is being tested in a research facility (UTIs). To establish diagnostic test parameters, the novel test is compared to urinalysis of a midstream urine specimen (considered the diagnostic gold standard). The trial includes 300 individuals, 100 of whom had a UTI as diagnosed by urinalysis. The novel dipstick test has been shown to be 70% sensitive and 90% specific for the identification of UTIs. The study has how many false positives?