Exam 3: Systematic Reviews and Meta-Analysis

Question 1

Difference between systemic review and narrative review

Answer 1

• Systemic review: identify, appraise, and synthesize all empirical evidence that meets pre-specified eligibility criteria to answer a given research question; explicit methods used to minimize bias
• narrative: qualitative summary of evidence on a given topic; informal and subjective methods to collect and interpret info (written by “expert” in field)

Question 2

types of review

Answer 2

• effectiveness of interventions
• accuracy of diagnostic tools
• identification of prognostic factors
• methodological factors

Question 3

who is Archibald Cochrane and what is he known for and why

Answer 3

-wrote book “effectiveness and efficiency: random reflections on health services” led to the development of the Cochrane collaboration

Question 4

Cochrane collaboration

Answer 4

• international not-for-profit organization dedicated to promotion of clinical trials evidence and development and dissemination of SRs of healthcare interventions
• primary product: Cochrane database of systematic reviews

Question 5

Cochrane review

Answer 5

-Def: SRs of research in healthcare and health policy that are published in the Cochrane database of SRs

Question 6

types of SRs published in Cochrane reviews

Answer 6

1. intervention reviews
2. diagnostic test accuracy reviews
3. methodology reviews

Question 7

the purpose of a systematic review

Answer 7

• to identify and combine studies using explicit methods to reduce bias
• do not typically define appropriate actions or incorporate values

Question 8

what is the process of conducting an SR?

Answer 8

state the study objective–>develop the protocol–>develop a search strategy–>conduct the search–>retrieve relevant papers–>screen and select papers that meet established criteria–>evaluate methodological quality of selected studies–>analyze and synthesize findings–>determine if stats data are sufficient for further analysis (if no, the report results of SR); if yes, analyze the effect size estimates–>report results of meta-analysis

Question 9

are PICO questions used in systematic reviews

Answer 9

yes, used to formulate the research question

Question 10

how is the research question for an SR defined?

Answer 10

• a well formulated question that guides the review process
• assists with determining: eligibility criteria, searching for studies, collecting data from included studies and presenting findings

Question 11

is the literature review for a systemic review exhaustive?

Answer 11

• yes??; need to pick ones specifically for your review
• select key words
• identify resources that include relevant information (Cochrane, previously published SRs, databases available, reference checking)

Question 12

what databases are searched when conducting a SR?

Answer 12

• search at least 3

- Medline, Embase, Cinahl, Web of Science, EBM reviews

Question 13

7 types of bias’ that can influence the outcome/quality of a SR

Answer 13

1. selection bias
2. confounding bias
3. allocation bias
4. performance bias
5. attrition bias
6. detection bias
7. reporting bias

Question 14

1. selection bias

Answer 14

may distort tx effects

-random allocation and concealment are essential

Question 15

2. confounding bias

Answer 15

systematic differences in factors related to intervention and outcome

Question 16

3. allocation bias

Answer 16

Systematic differences due to the way that tx groups are assemebled

Question 17

4. performance bias

Answer 17

differences in the provision of care to experimental and control groups
-blind those who receive and give care

Question 18

5. attrition bias

Answer 18

differential loss of subjects across comparison groups

-intention to treat analysis, people drop out

Question 19

6. detection bias

Answer 19

outcome differs across comparison groups

-quality assessment tools: quality assessment may provide explanations for differences in study results

Question 20

7. reporting bias

Answer 20

systematic differences between reported and unreported findings

Question 21

what are the rating scales used for an SR

Answer 21

• Jaded scale, Pedro scale, QUADAS scale
• no gold standard, most scoring systems have not been validated
• PT-related scales should take into account: pt adherence, standardization of tx protocol, precision of performance of intervention, validity, reliability, and responsiveness to the tests and measures

Question 22

how many people review the systematic review prior to its publication?

Answer 22

• minimum of 2 primary reviewers

- disagreement= describe if resolved by consensus or by resolution from a 3rd party

Question 23

how do you read a Forest Plot?/how is it constructed?

Answer 23

-has 5 odds ratios (squares, proportional to weights used in meta-analysis), with the summary measures (center line of diamond) and associated confidence intervals (lateral tips of the diamond), and a solid vertical line of no effect

Question 24

purpose of Forest Plot

Answer 24

-illustrates results of individual studies and a cumulative summary; visually understand the inconsistency in findings and large variance in several studies for this review

Question 25

what is meta-analysis?

Answer 25

statistically combining results from 2 or more separate studies to estimate an “average” or “common” effect
-improves the precision of the estimated treatment effect

Question 26

what are the two states in a meta-analysis?

Answer 26

Stage 1. calculation of confidence intervals for each study

• extraction of data from each individual study and the calculation of a result for each study with an estimate of the chance variation we would expect with studies like that
• Evaluate heterogeneity (chi-square test)

Stage 2: calculation of pooled average result across all studies

• give greater weight to the results from studies
• effect size, effect size index, weighting effect size

Question 27

what is the relationship between a meta-analysis and a SR

Answer 27

-SR refers to the entire process of selecting, evaluating, and synthesizing all available evidence, while meta-analysis refers to the statistical approach to combining the data derived from an SR

Question 28

What is PRISMA

Answer 28

Preferred Reporting Items for SRs and Meta-Analysis: a checklist for reporting them

• making sure it has all of the components
• abstract, intro, methods, results, discussion, funding