To qualify for federal contributions, provincial health insurance plans must guarantee all of the following, except:
Correct Answer B:
To qualify for federal contributions, provincial health insurance plans must guarantee portability of coverage from province to province, universal coverage on uniform terms and conditions, administration on a non-profit basis and benefits include all necessary hospital care and physicians' services. Benefits such as out-of-hospital drugs, dental care and prostheses are not part of the provincial health insurance plans.
Two medical students poll a random sample of classmates concerning their choices for residency training and find that the percentage of women who plan to train in primary care is significantly higher than the percentage of men (p < 0.05).
The probability is less than 5% that:
Correct Answer D: The p-value is a measure of how likely it is to get data if no real difference existed. Therefore, a small p-value (0.05) indicates that there is a small chance of getting this data if no real difference existed and therefore one decides that the difference in group expression data is statistically significant.
For example, in a study if the p-value is 0.05, that means that there is a 5% probability that the results are due to chance alone.
The results of a given study are reported as achieving significance at a p-value of < 0.05 (the 5% level).
True statements about this finding include which one of the following?
Correct Answer A: The p-value is a level of statistical significance, and characterizes the likelihood of achieving the observed results of a study by chance alone, and in this case that likelihood is < 5%. (In this case, < 5% of the results can be achieved by chance alone and still be significant).
→ The confidence interval is a measure of variance and is derived from the test data.
→ The p-value in and of itself says nothing about the truth or falsity of the null hypothesis, only that the likelihood of the observed results occurring by chance is 5%.
→ The alpha or type I error is akin to the error of false-positive assignment, 1 - specificity; the beta or type II error is analogous to the false-negative rate, or 1 - sensitivity, and cannot be calculated from the information given.
Echoviruses have been implicated as etiology of which one of the following diseases?
Correct Answer A:
More than 90% of community-acquired cases of viral and acute aseptic meningitis are caused by group B coxsackieviruses or echoviruses. Group B coxsackievirus serotypes 2-5 and echovirus serotypes 4, 6, 9, 11, 16, and 30 are found most commonly. Echoviruses can also cause encephalitis vesicular rashes and herpangina.
During development of a drug, the drug is studied first in animals and then in human beings. Clinical trials involve the study of investigational drug in human beings - either in normal healthy volunteers or in diseased subjects and are carried out in phases - 1, 2 and 3. Once approval to market a drug has been obtained, phase 4 begins. Drug may fail either in earlier phases of development or may be withdrawn after it is marketed.
Which phase of clinical trial has highest rate of drug failure?
Correct Answer C:
Drug development process is a dynamic process and unfortunately, only 10-15% of the new drugs that achieve marketing approval represent significant advances in safety and effectiveness; the remainder are merely molecular variants (“me-too drugs”) on true breakthrough drugs.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question. Clinical trials involving new drugs are commonly classified into four phases.
In phase 2 or “proof of concept”, the drug is studied in patients with the target disease to determine its efficacy. This is the first time when the drug is studied in diseased subjects. Both efficacy and safety in target disease is first studied in this phase and a broader range of toxicities may be detected in this phase. Thus, Phase 2 trials have the highest rate of drug failures - either drug fails due to efficacy or safety aspect.
→ Even though phase 0 studies are done in humans, this type of study is not much like the other phases of clinical trials. Phase 0 studies are exploratory studies that often use only a few small doses of a new drug. Phase 0 studies help researchers find out whether the drugs do what they are expected to do.
→ In phase 1, the effects of the drug as a function of dosage are established in a small number (20-100) of healthy volunteers. Phase 1 trials are done to determine the probable limits of the safe clinical dosage range. Many predictable toxicities are detected in this phase. So efficacy and safety aspect of the drug in target disease is not sought in this phase.
→ In phase 3, the drug is evaluated in much larger numbers of patients with the target disease, usually thousands, to further establish and confirm safety and efficacy. Phase 3 trials are usually performed in settings similar to those anticipated for the ultimate use of the drug. Only 25% of innovative drugs move on to phase 3.
→ Once approval to market a drug has been obtained, phase 4 begins. This constitutes monitoring the safety of the new drug under actual conditions of use in large numbers of patients.
Key point:
Clinical trials involving new drugs are commonly classified into four phases. Phase 2 trials have the highest rate of drug failures.
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