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165 Cards in this Set
- Front
- Back
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What is a case-control study classified as?
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Observational and retrospective
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How is a case-control study designed?
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Compares a group of people with disease to a group without.
Asks "what happened?" |
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What is measures in a case-control study?
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Odds Ratio (OR): Patients with COPD had higher odds of a history of smoking than those without COPD.
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What is a cohort study classified as?
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Observational and prospective
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How is a cohort study designed?
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Compares a group with a given risk factor to a group without to assess whether the risk factor increases the likelihood of disease
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What is measured in a cohort study?
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Relative risk (RR): Smokers had a higher risk of developing COPD than did nonsmokers
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What is a cross-sectional study classified as?
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Observational
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How is a cross-sectional study designed?
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Collects data from a group of people to assess frequency of disease (and related risk factors) at a particular point in time
Asks "what is happening?" |
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What is measured in a cross-sectional study?
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Disease prevalence
Can show risk factor association with disease but does not establish causality |
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What does a twin concordance study measure?
How? |
Measures heritability
Compares the frequency with which both monozygotic twins or both dizygotic twins develop a disease |
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What does adoption study measure?
How? |
Measures heritability and influence of environmental factors
Compares siblings raised by biologic vs adoptive parents |
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Name 5 kinds of studies
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Case-control
Cohort Cross-sectional Twin concordance Adoption |
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What is a phase I clinical trial?
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Small number of patients, usually healthy volunteers
Assesses safety, toxicity, and pharmacokinetics |
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What is a phase II clinical trial?
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Small number of patients with disease of interest
Assesses treatment efficacy, optimal dosing, and adverse reactions |
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What is a phase III clinical trial?
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Large number of patients randomly assigned either to the treatment under investigation of to the best available treatment (or placebo)
Compares new treatment to the current standard of care - More convincing if double-blinded |
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What is a meta-analysis?
How important is it? What are its faults? |
Pools data from several studies to come to an overall conclusion. Achieves greater statistical power and integrates results of similar studies.
Highest eschelon of clinical evidence. May be limited by quality of individual studies or bias in study selection |
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Draw the 2 x 2 box of false/true, positive/negative
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P. 61
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What is sensitivity?
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Proportion of all people with disease who test positive
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How do you use sensitivity?
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Value approaching 1 is desirable for ruling OUT disease and indicates a low false-negative rate
**SNOUT = SeNsitivity rules OUT Used for screening in diseases with low prevalence |
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How do you calculate sensitivity?
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= TP/(TP+FN)
= 1 - false-negative rate |
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What is specificity?
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Proportion of all people without disease who test negative
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How do you use specificity?
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Value approaching 1 is desirable for ruling IN disease and indicates a low false-positive rate
**SPIN = SPecificity rules IN Used as a confirmatory test after a positive screening test |
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Explain using HIV testing how to use sensitivity/specificity
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Screen with ELISA (sensitive, high false-positive rate, low threshold)
Confirm with Western blot (specific, high false-negative rate, high threshold) |
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How do you calculate specificity?
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= TN/(TN+FP)
= 1 - false-positive rate If 100% specificity, TN/(TN+FP) = 1 FP = 0 and all positives must be TPs |
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What is positive predictive value?
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Proportion of positive test results that are true positive
Probability that person actually has the disease given a positive test result |
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How do you calculate PPV?
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= TP/(TP+FP)
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What extra do you need to think about with PPV and how it relates to sensitivity/specificity?
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If the prevalence of a disease is low, even tests with high specificity or high sensitivity will have low PPV
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What is negative predictive value?
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Proportion of negative test results that are true negative
Probability that person is actually disease free given a negative test result |
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How do you calculate NPV?
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= TN/(FN+TN)
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What is the equation for point prevalence?
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Total cases in population at a given time / total population at risk at a given time
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What is the equation for incidence?
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New cases in population over a given time period / total population at risk during that time
**Incidence is new incidents - people previously positive for a disease are no longer considered at risk |
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How do prevalence and incidence relate?
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Prevalence = incidence x disease duration
(Roughly) Prevalence > incidence for chronic diseases Prevalence = incidence for acute disease |
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What is odds ratio?
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OR for case control studies: odds of having disease in exposed group divided by odds of having disease in unexposed group
= a/b / c/d = ad/bc See p. 62 |
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What is relative risk?
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Relative risk for cohort studies: relative probability of getting a disease in the exposed group compared to the unexposed group
Calculated as percent with disease in exposed group divided by percent with disease in unexposed group = a/(a+b) / c/(c+d) See p. 62 |
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What is attributable risk?
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The difference in risk between exposed and unexposed groups, or the proportion of disease occurences that are attributable to the exposure
Ex. Smoking causes 1/3 cases of pneumonia |
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What is precision?
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The consistency and reproducibility of a test (reliability)
The absence of random variation in a test |
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What is accuracy?
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Trueness of test measurements (validity)
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What does random error cause?
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Reduced precision in a test
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What does systematic error cause?
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Reduced accuracy in a test
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Draw the targets of accuracy, precision, accuracy and precision, neither
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P. 62
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What does bias occur?
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When 1 outcome is systematically favored over another
Systematic errors |
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Name 9 kinds of bias
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Selection
Recall Sampling Late-look Procedure Confounding Lead-time Pygmalion Hawthorne effect |
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What is selection bias?
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Nonrandom assignment to study group
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What is recall bias?
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Knowledge of presence of disorder alters recall by subjects
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What is sampling bias?
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Subjects are not representative to general population; therefore, results are not generalizable
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What is late-look bias?
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Information gathered at an inappropriate time
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What is procedure bias?
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Subjects in different groups are not treated the same
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What is confounding bias?
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Occurs with 2 closely associated factors; the effect of 1 factor distorts or confuses the effect of the other
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What is lead-time bias?
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Early detection confused with increased survival
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What is Pygmalion effect?
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Occurs when a researcher's belief in the efficacy of a treatment changes the outcome of the treatment
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What is the Hawthorne effect?
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Occurs when the group being studied changes its behavior to meet the expectations of the researcher
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Name 4 ways to reduce bias
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Blind studies (double-blind even better)
Placebo responses Crossover studies (each subject is his own control) Randomization |
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Draw and define normal distribution
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P. 63
Gaussian Bell shaped Mean = median = mode |
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Draw and define bimodal distribution
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P. 63
2 humps |
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Draw and define positive skew
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P. 63
Mean > Median > Mode Assymetry with tail on right |
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Draw and define negative skew
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P. 63
Mean < Median < Mode Assymetry with tail on left |
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What is least affected by outliers?
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Mode
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What is the null hypothesis?
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Hypothesis of no difference
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What is the alternative hypothesis?
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Hypothesis that there is some difference
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Draw the 2 x 2 box of statistical hypotheses
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P. 63
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What is a Type I (alpha) error?
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Stating that there IS an effect or difference when there isn't
Mistakenly accept the hypothesis and reject the null hypothesis "False-positive" error - convicted an innocent man |
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How does p relate to a Type I error?
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p = probability of making a type I error
p is judged against alpha, a present level of significance (usually .05) |
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What is a Type II (beta) error?
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Stating that there is NOT an effect or difference when one exists
Fail to reject the null hypothesis when you should have "False-negative" error - set a guilty man free |
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What is power?
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Probability of rejecting null hypothesis when it is in fact false, or the likelihood of finding a difference if one in fact exists
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What 3 things does power depend on?
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Total number of end points experienced by population
Difference in compliance between treatment groups (differences in mean values between groups) Size of expected effect |
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How do you calculate power?
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1 - beta
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How do std dev and std error compare?
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SEM = std dev/ square root of sample size
SEM < std dev SEM decreases as n increases |
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Draw the normal (Gaussian) distribution with std devs
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P. 64
68% 95% 99.7% |
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What is a confidence interval?
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Range of values in which a specified probability of the means of repeated samples would be expected to fall
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How is a confidence interval calculated?
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CI = range from [mean - Z(SEM)] to [mean + Z(SEM)]
For the 95% CI, Z = 1.96 If the 95% CI for a mean difference includes 0, then there is no significant difference and null hypothesis is not rejected If the 95% CI for odds ratio or relative risk includes 1, null hypothesis is not rejected |
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What does a t-test measure?
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Difference between means of 2 groups
**Mr. T is MEAN |
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What does ANOVA measure?
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Difference between means of 3 or more groups
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What does chi-squared measure?
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Difference between 2 or more percentages or proportions of categorical outcomes (not mean values)
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What is a correlation coefficient, r?
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Always between -1 and 1
Closer the absolute value is to 1, the stronger the correlation between the 2 variables |
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What is the coefficient of determination?
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r^2
This is how correlation coefficient is usually reported |
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What is primary prevention?
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Prevent disease occurrence
Ex. vaccination |
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What is secondary prevention?
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Early detection of disease
Ex. Pap smears |
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What is tertiary prevention?
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Reduce disability from disease
Ex. Exogenous insulin for diabetes |
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Name some important preventions for diabetes
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Eye, foot exams
Urine tests |
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Name some important preventions for drug use
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Hepatitis immunizations
HIV, TB tests |
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Name some important preventions for alcoholism
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Influenza, pneumococcal immunizations
TB test |
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Name some important preventions for overweight
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Blood sugar test
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Name some important preventions for homeless, recent immigrant, inmate
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TB test
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Name some important preventions for high-risk sexual behavior
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HIV
Hep B Syphilis Gonorrhea Chlamydia |
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Name 14 reportable diseases
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** Hep, Hep, Hep, Hooray, the SSSMMART Chick is GONe!
Hep A, Hep B, Hep C, HIV, Salmonella, Shigella, Syphilis, Syphilis, Measles, Mumps, AIDS, Rubella, TB, Chickenpox, Gonorrhea |
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Name 5 leading causes of infant death in US
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Congenital anomalies
Short gestation/low birth weight SIDS Maternal complications of pregnancy Respiratory distress syndrome |
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Name 5 leading causes of death in US of 1-14 year olds
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Injuries
Cancer Congenital anomalies Homicide Heart disease |
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Name 5 leading causes of death in US of 15-24 year olds
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Injuries
Homicide Suicide Cancer Heart disease |
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Name 5 leading causes of death in US of 25-64 year olds
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Cancer
Heart disease Injuries Suicide Stroke |
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Name 5 leading causes of death in US of 65+ year olds
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Heart disease
Cancer Stroke COPD Pneumonia Influenza |
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What are Medicare Parts A and B?
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A = hospital
B = doctor bills |
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Name 4 core ethical priniciples
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Autonomy
Beneficence Nonmaleficence Justice |
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What is autonomy?
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Obligation to respect patients as individuals and to honor their preferences in medical care
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What is beneficence?
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Physicians have special ethical (fiduciary) duty to act in patient's best interest
May conflict with autonomy - ultimately, patient has right to decide |
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What is nonmaleficence?
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"Do no harm"
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What is justice?
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To treat persons fairly
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Name 3 parts of informed consent
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Discussion of pertinent information
Patient's agreement to plan Freedom from coercion |
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Name 4 exceptions to informed consent
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Patient lacks decision-making capacity or is legally incompetent
Implied consent in emergency Therapeutic privilege - withholding information when disclosure would severely harm the patient of undermine informed decision-making capacity Waiver - patient waives right to informed consent |
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Name 5 components of decision-making capacity
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Patient makes and communicates a choice
Patient is informed Decision remains stable over time Decision is consistent with patient's values and goals Decision is not a result of delusions or hallucinations |
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What is oral advance directive?
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Incapacitated patient's prior oral statements commonly used as a guide
Problems arise from variance in interpretation |
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What makes oral advance directive more valid?
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Patient was informed
Directive is specific Patient made a choice Decision was repeated over time |
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Name 2 kinds of written advance directives
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Living will
Durable power of attorney |
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What is a living will?
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Describes kinds of treatments patient wishes to receive or to not receive
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What is a durable power of attorney?
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Patient designates a surrogate to make medical decisions
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Name 4 exceptions to confidentiality
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Potential harm to others is serious
Likelihood of harm to self is great No alternative means exist to warn/protect others Physicians can take steps to prevent harm |
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Name 5 examples of confidentiality exceptions
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Infectious diseases
Tarasoff decision - potential victim Child/elder abuse Impaired automobile drivers Suicidal/homicidal patients |
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Name 4 parts of malpractice negligence
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4 D's
Duty Dereliction Damage Direct |
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What is the Good Samaritan law?
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Relieves health care workers from liability in certain situations
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What to do when patient is noncompliant?
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Work to improve relationship
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What to do when family members ask for info
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Avoid discussing without permission of patient
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What to do if a 17 year old girl asks for abortion
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Many states require parental notification or consent for minors
Parental consent not required for medical care during pregnancy |
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What does APGAR stand for?
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Appearance: Blue/trunk pink/all pink
Pulse: None/ < 100/min / > 100/min Grimace: None/ Grimace/ Grimace and cough Activity: Limp/ Some/ Active Respiration: None/ Irregular/ Regular Evaluate at 1 and 5 minutes |
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What is low birth weight?
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Defined as < 2500 g
Caused by prematurity or intrauterine growth retardation |
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Name 5 complications of low birth weight
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Infections
Respiratory distress syndrome Necrotizing enterocolitis Intraventricular hemorrhage Persistent fetal circulation |
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Name a motor and cognitive/social milestone for birth-3 months
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Rooting reflex
Orients to voice |
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Name a motor and cognitive/social milestone for 3 months
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Holds head up, Moro reflex disappears
Social smile |
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Name a motor and cognitive/social milestone for 4-5 months
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Rolls front to back, sits when propped
Recognizes people |
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Name a motor and cognitive/social milestone for 7-9 months
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Sits alone, crawls
Stranger anxiety |
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Name a motor milestone for 12-14 months
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Upgoing Babinski disappears
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Name a motor and cognitive/social milestone for 15 months
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Walks
Few words, separation anxiety |
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Name a motor and cognitive/social milestone for 12-24 months
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Climbs stairs, stacks 3 blocks
Object permanence; 200 words and 2-word sentences at age 2 |
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Name a motor and cognitive/social milestone for 18-24 months
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Stacks 6 blocks
Rapprochement |
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Name a cognitive/social milestone for 24-48 months
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Parallel play
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Name a cognitive/social milestone for 24-36 months
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Core gender identity
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Name a motor and cognitive/social milestone for 30-36 months
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Stacks 9 blocks (number of blocks stacked = age in years x 3)
Toilet training (Pee at 3) |
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Name a motor and cognitive/social milestone for 3 yrs old
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Rides tricycle, copies line or circle drawing
900 words and complete sentences |
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Name a motor and cognitive/social milestone for 4 years old
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Simple drawings (stick figure), hops on 1 foot, copies a cross
Cooperative play, imaginary friends, grooms self, brushes teeth, buttons and zips |
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Name a motor and cognitive/social milestone for 6-11 years old
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Rides bicycle, copies a triangle (age 6)
Reads, understands death, development of conscience, same-sex friends, identification with same-sex parent |
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Name a cognitive/social milestone for 11 years old (girls) and 13 years old (boys)
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Abstract reasoning (formal operations)
Formation of personality |
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Name the Tanner stages
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1. Childhood
2. Pubic hair begins to develop (adrenarche), increased size of testes, breast tissue 3. Increased pubic hair, darkens, curly, increase in penis size/length 4. Increase in penis width, darker scrotal skin, development of glans, raised areolae 5. Adult; areolae are no longer raised |
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Name 8 categories of changes in the elderly
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Sexual changes
Sleep patterns Common medical conditions Psychiatric disorders lower prevalence Increased suicide rate Decreased vision, hearing, immune response, bladder control Decreased renal, pulmonary, GI function Decreased muscle mass, increased fat |
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What sexual changes occur in the elderly?
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Men - slower erection/ejaculation, longer refractory period
Women - vaginal shortening, thinning, and dryness No change in sexual interest |
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What sleep changes occur in the elderly?
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Decreased REM sleep
Decreased slow-wave sleep Increased sleep latency Increased awakenings during night |
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What 4 common medical conditions occur in the elderly?
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Arthritis
Hypertension Heart disease Osteoporosis |
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How does the suicide rate change in the elderly?
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Increased
Men 65-74 have highest rate in US |
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What is grief?
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Normal bereavement characterized by shock, denial, guilt, and somatic symptoms
6 months - 1 year |
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What is pathologic grief?
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Excessively intense or prolonged grief or grief that is delayed, inhibited, or denied
May experience depressive symptoms, delusions, and hallucinations |
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Name the 5 Kubler-Ross grief stages
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Denial
Anger Bargaining Grief (depression) Acceptance |
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Name 9 effects of stress
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Production of:
Dree fatty acids 17-OH corticosteroids (immunosuppression) Lipids Cholesterol Catecholamines Affects water absorption, muscular tonicity, gastrocolic reflex, and mucosal circulation |
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Name 3 differential diagnoses for sexual dysfunction
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Drugs (antihypertensives, neuroleptics, SSRIs, ethanol)
Diseases (depression, diabetes) Psychological (anxiety) |
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How is BMI measured?
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Weight adjusted for height
Weight in kg/ (height in m)^2 |
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What are the different BMI categories?
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< 18.5 = underweight
18.5 - 24.9 = normal 25 - 29.9 = overweight > 30 = obese |
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Name the sleep stages and how much time is spent in each
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1 (5%)
2 (45%) 3-4 (25%) REM (25%) |
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What is Stage 1 sleep?
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Light sleep
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What kind of EEG is seen in Stage 1 sleep?
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Theta
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What is Stage 2 sleep?
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Deeper sleep
Bruxism |
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What kind of EEG is seen in Stage 2 sleep?
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Sleep spindles and K complexes
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What is Stage 3-4 sleep?
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Deepest, non-REM sleep
Sleepwalking Night terrors Bedwetting (slow-wave sleep) |
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What kind of EEG is seen in Stage 3-4 sleep?
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Delta (lowest frequency, highest amplitude)
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What is REM sleep?
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Dreaming, loss of motor tone, possible a memory processing function, erections, increased O2 use
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What kind of EEG is seen in REM sleep?
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Beta (highest frequency, lowest amplitude)
**At night, BATS Drink Blood (Beta, Alpha, Theta, Spindle, Delta, Beta) |
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What kind of EEG is seen in awake/eyes open?
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Beta (highest frequency, lowest amplitude)
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What kind of EEG is seen in awake/eyes closed?
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Alpha
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What initiates sleep?
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Serotonergic predominance of raphe nucleus key to initiating sleep
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What reduces REM sleep?
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NE
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What causes extraocular movements during REM?
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Activity of PPRF
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Name 2 drugs used for sleep problems
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Benzodiazepines shorten stage 4 sleep - useful for night terrors and sleepwalking
Imipramine - shortens stage 4 sleep, used for enuresis |
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What happens during REM sleep?
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Increased and variable pulse
REM Increased and variable BP Penile/clitoral tumescence Occurs every 90 minutes |
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What is the principal neurotransmitter involved in REM sleep?
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Ach
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What happens to REM over time?
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Decreases with age
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What is narcolepsy?
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Disordered regulation of sleep-wake cycles
May include hypnagogic (just before sleep) or hypnopompic (just before awakening) hallucinations Patient's nocturnal and narcoleptic sleep episodes start off with REM sleep |
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What is cataplexy?
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Loss of all muscle tone following strong emotional stimulus
Can happen to some narcoleptic patients |
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How do you treat narcolepsy?
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Stimulants - amphetamines, modafinil
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What drives circadian rhythms?
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Suprachiasmatic nucleus of hypothalamus
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What does SCN control?
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ACTH, prolactin, melatonin, nocturnal NE release
SCN --> NE release --> pineal gland --> melatonin SCN is regulated by environment (light) |
