What is a Primary Resource? 

- Dissertations and Theses

- Conference Proceedings

- Scientific articles reporting experimental research results, case reports or clinical trials 

-Current

-Original

-"Cutting-edge"

-Specific 

- Flaws in methodology may lead to inaccurate conclusions

- Knowledge of scientific methods and statistics is necessary to properly interpret information 

- Simplifies the process of finding and evaluating the primary literature

- Could be an indexing service (provides bibliographic information that is indexed by topic)

- Could be an Abstracting Service (Provides same info as the indexing service but also provides brief descriptions of information) 

-PubMed

-IDIS

- ProQuest Medical Library

- International Pharmaceutical Abstracts

-Science Citation Index 

- Provide simplified access to primary literature

-Provide access to a large scope of information on a specific topic 

- Lag time between publication and inclusion in secondary sources varies

-You must be proficient in searching a variety of secondary sources 

- Reference Books

- Textbooks

- Drug Compendia

- Review Articles

- Systematic Reviews

- Practice Guidelines 

- Published after examination of previously published material on a subject

- Material reviewd may be broad or psecific and can encompass, in medicine specifically, clinical material as well as experimental research or case reports 

- Consist of a set of direction or principles to assist health care practitioners with patient care decisions.

- Developed by government agencies, institutions, organizations, or by the convening of expert panels.

- Provide a foundation for assessing and evaluating the quality and effectiveness of health care.   

- Convenient and generally accessible

- Information is usually well accepted

- Most tertiary resources are referenced with primary literature sources. 

- Information may be dated

- Texts are organized to suit purpose of author and may not meet your need

- Often need to compare and verify information in another resource 

- First place to look for background information.

-First place to look for "quick answer" in terms of disease state information, general drug information, and general reference information. 

If a call number given is......

WB

100

H322p

1998

What does each line stand for?

WB100 - Subject of the book, in this case "Practice of Medicine

H322p - This line represents the author's last name or title

1998 -  This last line represents the publication date.

What is Micromedex good for?

- Basic drug information

- Checking single and multiple drug interactions

- Finding alternative medicine information

- Comparing drug summaries

- Finding patient education information

- Identifying drugs based on tablet markings

- Basic Drug Information

- Product Identification

- Checking for Drug Interactions

- Finding drugs by indication

- Alternative medicine information

- Drug comparisons

Clinical Pharmacology is also very good in regard to a kind of report that pertains to this question......

"Would amitriptyline or fluoxetine be a better treatment choice for fibromyalgia in a patient that has closed-angle glaucoma?"

What is the Cochrane Collaboration?

- Volunteer health care professionals who work in groups to prepare the reviews. 

- Also, editorial teams to oversea the preparation and maintenance of the reviews, as well as application of the rigorous quality standards.

- Published quarterly, resource contains full text reviews of medical literature

- The reviews are highly structured and systematic, with evidence included or excluded on the basis of explicit quality criteria, to minimize bias.

- Data is evidence-based and is often combined statistically (with meta-analysis) to increase the power of the findings of numerous studies, each too small to produce reliable results individually.   

- Objectives

- Background

- Criteria for Considering Studies for this Review

- Search Strategy for Identification of Studies

- Method of the Review

- Description of Studies

- Methodological Quality

- Results

- Discussion

- Reviewers Conclusions

- Potential Conflict of Interest

- Acknowledgements

- Synopsis

- References

- Tables and Graphs

- Table of Included Studies

- Table of Excluded Studies

- Comments and Criticisms

- Reviewer's Reply

- Contributors Comments 

The HON code are 8 principles designed to serve as quality assurance criteria for web sites containing medical or health information.  These principles are......

1.  Authority

2.  Complementarity

3.  Confidentiality

4.  Attribution

5.  Justifiability

6.  Transparency of authorship

7.  Transparency of sponsorship

8.  Honesty in advertising and editorial policy 

- Boolean searching

- Phrase searching

- Plus/Minus syntax

- Truncation

- Case sensitivity

- Field searching 

Caveat Lector (whatever that means):

1.  Utilize Library Resources

2.  Use recommended websites (Medline, National Guidelines Clearinghouse)

3.  Use advanced searching tools

4.  Apply the HON Code Principles 

1.  Abstract and Title

2. Investigators

3.  Introduction and Objectives - Purpose of the study

4.  Methods - how was the study conducted?

5.  Statistical Analysis

6.  Results - what was found in the study

7.  Discussion and Conclusion - Interpretation of the data

8.  References

9.  Funding Sources 

- Is it a reputable journal?

- Is it a specialty journal?

- Is the paper peer reviewd? Should be

- Was the paper presented at a meeting? 

- Is the title interesting (who cares)?

- Is there bias in the title (who cares about the title)? 

- Were the investigators qualified to conduct the research?

- Are the investigators associated with major institutions?

- Is there a biostatistician involved in the research? 

- Are the questions addressed by the study of interest to you?

- Are the patients similar to your patients?

- Does the design seem reasonable? (for example long terms outcomes and the study lasted a short time)

 - Are the results clearly written?

- Are the results significant? Differences identiied?

- Do the conclusions accurately reflect the results? 

- Why was the study done and what questions were the investigators addressing?

- The introductory section of a paper should state the background to the research and provide a brief review of published literature.

- Are the objectives reasonable? 

- Patient population

- Study Design

- Treatment description

- Outcomes defined

- Statistics 

- Are the subjects patients or healthy volunteers?

- Do the patients represent patients one would encounter with the disease?

- Are the criteria for severity of disease appropriate?

- Are the exclusion criteria appropriate?

- Are the excluded patients accounted for in the study?

- Do the excluded patients limit the applicability of the study? 

- What type of study is it?  Is it appropriate?

- Are the patients homogenous after assignment to treatment group?

- Are all the specifics related to treatment clearly stated?

- Was the placebo identical to active drug?  Was there blinding?

- Was adherence checked?

- Were the dose and duration of treatment appropriate? 

- Were all the measures standardized?

- Were the measurements appropriate to show the effect of the drug?

- Were the measurements sensitive enough to show changes caused by the drug?

- Were the measurements objective?

- Were side effects measured?  Were all the patients asked about side effects in the same manner? 

- All signs and symptoms of infection had resolved

- Blood cultures at the end of therapy and at all follow-up visits were negative

- Associated signs of inflammation had resolved 

- Are the tests described?

- Are the tests appropriate for the data?

- Were the tests chosen prior to data collection?

- Are the P values significant?

- Is power defined?

- Are the confidence intervals included?

- Is there an intent to treat analysis? 

- Indicates the limits within which the real difference between the treatments is likely to lie. 

- A 95% CI for a parameter consists of the upper and lower limits determined so that, in many repeated samples of the same size 95% of all such intervals would be expected to contain the parameter.   

- Are the results clearly presented, current, and relevant. 

- Are all of the patients accounted for?

- Aare baseline characteristics of patients presented?

- Is all of the data presented - microbiology, course of therapy, toxicity, outcomes, failures, and relapses, follow-up and deaths, endophthalmitis, management of intravascular catheters.

- Do the results match the outcomes objectives of the study? 

- Are the reasons for withdrawal clearly stated?

- Are the number of withdrawals acceptable? (<10% short term)

- Are the statistics reported as exact P values and confidence intervals?

- Does statistical significance necessarily imply clinical signficance? 

- Do the conclusions match the data presented in the study?

- Are the conclusions confiend to the data in the study?

- Do the conclusions compare the study results to other published data?

- Did the author discuss the study limitations and strengths 

- Are the references up to date?

- Are the authors cited to a limited degree?

- Are landmark articles cited? 

- That the "cause" precedies the "effect" in time

- That the "cause" and the "effect" are related

- That there are no plausible alternative explanations for the observed covariation.

- Temporal relationship is unclear

- Selection bias

- Historical change

- Participant maturation

- Loss of participants

- Testing effects

- Instrumentation change

- Small samples obtained from a single geographic location

- Experiments that employ strict inclusion/exclusion criteria.

Problem: Because of these threats, one can not be sure that any results obtained would apply to people in other geographic locations.  

- A bias resulting from a flaw in a process, or measurement. 

- How were patients identified?

- What measurements were taken?  

Problem: As a consequence, systematic bias commonly leads to systematic errors, as opposed to random errors, which tend to cancel one another out.

- This is when we separate the population into non-overlapping groups --> strata

- Specific factor will be contained in separate strata to aid in analysis.  Example: Sex 

- Measures of central tendency

- Measures of variability

- Measures of shpae

- Measures of disease frequency

- Incidence and prevalence

- Measures of association

- Sensitivity, specificity, and predictive values

- Distributions 

Central limit theorem

- Parametric versus nonparametric testing

- Hypothesis testing

- Errors (Type I and Type II)

- Significance

- Statistical testing 

- Most frequently occuring value

- > 1 mode

- Any scale of measurement 

- Value at the 50th percentile

- Ordinal, interval, ratio scale 

- Average numerical value for the data set

- Interval or ratio scale

- Heavily influenced by outliers 

- Difference between the highest data value and the lowest value

- Ordinal, interval, and ratio data 

- Data values within the 25th and 75th quartiles.

- Directly related to the median

- Less likely to be affected by extreme values in the data

- Ordinal, interval, and ratio data 

- Measures of symmestry of a curve

- Tells how well each half of hte curve of distribution relates to the other half of a normal distribution.

- Positive versus negative 

- How flat or peaked the curve appears

- Platykurtic (flat) vs. Leptokurtic (thin,more peaked)

Used to describe iterval and ratio data.  Used to determine statistical tests 

- Ratio

- Proportions

- Rates

- General term that expresses the relationship between two numbers

- Calculated simplybi dividing one quantity by another without implying any specific relationship between the numerator and the denonminator

- An example is the ratio of men to women who suffer from multiple sclerosis (MS) 

A type of ratio in which the numerator is included in the denominator.

- This ratio is part of the whole and is often expressed aas a percentage.  Example: The percentage of men with MS would be the number of men with MS in the numerator divided by the number of people in the population with MS. 

- Special form of proportion that includes a specific time frame.

- The rate is equal to the number of events in a specificed period divided y the population at risk in a specific time peroid.  

- Direct relationship between the numerator and denominator (measure of time is an intrinsic part of the denominator)

- Example: Teh rate of MS would be the number of cases during a specified time period, such as 1 year, divided by the total population in that time frame.   

- The number or rate of cases that exist (prevail) at a specified time

- The proportion of people who have a given disease or condition at a specified point in time.   

- The occurrence of new cases during a specified period of time

- A rate giving the proportion of people who develop a given disease or condition within a specified period of time. 

This is the.....

Number of new cases of a disease per a given time frame/ population at risk. 

The incidence rate is..

The number of new cases of a disease during time/ total person-time of observation 

- The proportion of people who becoem diseased during a specified period of time.

- The relevent time period must be specified when reporting CL

- Assumes the entire population at risk at the beginning of the study period has been followed for the specific time interval for the development of the outcome under investigation.  

- Range 0-1 

- Measure of the instantaneous rate of development of disease in a population

- The denominator is the sum of each individual's time at risk or the sum of time that each person remained under observation and free of disease

- Range 0-infinity 

- Measures of association are formed to compare measures of frquency for more than 2 groups

- Comparisons are intended to identify characteristics associated with the presence/absence of treatment or exposure. 

- The ratio of the incidence of a given disase in exposed or at risk persons to the incidence of the disease in unexposed persons. 

- A measure of the association between exposure and dissae.

- Ratio of incidnece in exposed persons to incidence in non-exposed persons.   

The odds that a patient was exposed to a given risk factor divided by the odds that a control was exposed to the risk factor. 

- The probability of occurrence over the probability of nonoccurrence.

- A measure of prevalence

- An estimate of the relative risk.   

Odds ratio is an estimate of relative risk (often overestimate relative risk).

- Range of values: 0 - infinity

- Pivot on 1.0 (no difference) 

- In no way indicates the magnitude of incidence/prevalence rates in exposed/non-exposed grups

- Size helps in deciding whether the association between the antecedent risk factor and the disease is a likely part of the cause (Identifying causal relationships, if the RR is very large, regardless of the  respective incidence rates, a causative association is more likely) 

- Sensitivity

- Specificity

- Positive preditive value

- Negative predictive value 

Define the following terms....
True Positives

False Positives

True Negatives

False Negatives 

TP - Individuals with the disease who were correctly identified

FP - Individuals without the disease who were incorrectly identified as having the disease by the test.

TN - Individuals without the disease who were correctly identified as disease free by the test.  

FN - Individuals with the disease who were incrorectly identified as disease free by the test.   

-  The ability of a test to reliably detect the presence of disease (positivity of the test) when the disease is present.

- Sensitivity = TP/ (TP + FN)

- Sensitivity = a/(a+c) 

The ability of a test t oreliably detect the absence of disease (negativity of the test) when the disease is absent

- Specificity = TN/ (TN + FP)

- Specificity = d/b+d 

- Predictive values can be used to help predict the likelihood of disease in an individual.

- Positive predictive value is useful to indicate the proportion of individuals who actually have the diasease when the diagnostic test indicates the presence of that disease.  

- Negative predictive value is useful to determine the proportion of individuals who are truly free of the disease tested for when the diagnostic test indicates the absence of that disease 

When investigators have a priori expection about the sample value they expect to observe, and they want to test whether it is larger or smaller.

- Statistical signficance can be obtained with a smaller departure from the hypothesized vlaue.  It is important to note that two-sided tests are considered statistically stronger.   

- Valid only when characteristics follow or nearly follow the normal distribution in the population studied.

- Can be applied properly to most interval and ratio scale data when those data come from a sample of a normally distributed population.  

- Can be used to derive measures of central tendency and variability 

Non-parametric methods are applied to non-normally distributed data and/or data that do not meet the criteria for use of parametric methods.

- Data that fit the ordinal scale definition should be analyzed by non-parametric methods (Apgar Score, Glasgow Coma Scale, Trauma Score, Injury Severity Score) 

- Inferential statistics generate P values. 

-The calculated p value is the probability that the result observed in the study is entirely due to chance.

- Data are considered statistically signficiant when the calculated p values is less than alpha or the level of significance 

- False negative results (Type II error)

- Sample may not represent population

- Overestimation of treatment effects