1. Journal Club Notes Pragmatic VS Explanatory Reviews and Systematic Reviews

2. Brady Et Al., "sequential compression device compliance in postoperative obstetrics and gynecology patients", obstetrics and gynecology, vol. 125, no. 1, january 2015.

3. Pragmatic vs. explanatory
Clinical trials can be characterized into two groups -- explanatory and pragmatic
Explanatory trial -- designed to test the efficacy of an intervention under optimal conditions
RCTs fall into this category
Higher internal validity -- better control of bias
Lower external validity -- less likely to be generalized and applicable to most patients
Assesses If and how intervention works

4. Pragmatic vs. explanatory
Pragmatic trial - designed to evaluate the effectiveness of an intervention in real-world practice situations
Higher external validity than a controlled experiment
Addresses whether the intervention works in real life
Policymakers interested in pragmatic trials, especially given limited resources

5. strongly pragmatic trial
No exclusion / inclusion criteria
No guidelines for providers on how to apply the intervention
Comparison is the best alternative treatment
Intervention and comparison treatment applied across all clinical settings
No formal follow-up
Clinically meaningful primary outcome
No additional effort to increase compliance or adherence to trial's protocols
Patients analyzed in intention-to-treat fashion

6. Pragmatic vs. explanatory
Most trials are somewhere in-between
Have elements of both pragmatic and explanatory trials
Several tools have been developed to assess the degree to which a trial is pragmatic vs. explanatory

7. some control in this study
Exclusion criteria
Non-English speaking patients
Patients who had surgery for gynecologic malignancy
Post-op gyn and postpartum patients at Virginia Commonwealth University Healthy System
All observations made by the same two investigators

8. Statistical tests
Tukey's Honest Significant Difference Test -- could be be used alone or with ANOVA "post hoc", i.e., after the experiment is concluded, to compare all possible pairs of means in a single step
Compared all possible combinations of the four means in a single step
T-test can only compare two means at a time

9. RUSSO ET AL., "INTERVENTIONS IN PREGNANCY AND RISK OF GESTATIONAL DIABETES MELLITUS: A SYSTEMATIC REVIEW AND META-ANALYSIS

10. systematic review Terminology
Systematic review -- Review of a clearly specified question that uses a systematic and explicit method to identify, select and critically appraise the research
Collect and analyze data from included studies
Specified question: What is the effect of physical activity-only interventions on the risk of GDM?
Study reports search criteria, study inclusion criteria, and critical appraisal methods

11. systematic review terminology
Meta-analysis -- statistical method which combines and summarizes the results of studies that address the same question
Study reports summary estimate of the association between physical activity and GDM; RR=0.72; p<.01
Fixed effects -- effects of the intervention do not vary across studies; only vary within the studies
Random effects -- effects of the intervention vary across studies and within studies

12. systematic review terminology
Heterogeneity -- refers to the variability between studies in terms of characteristics, quality or effect
Low heterogeneity in this study (12%)
Interpreting I2 statistic
0-30% -- no or low heterogeneity
30-50% -- moderate heterogeneity
over 50% -- significant heterogeneity

13. systematic review terminology
Funnel plot -- graphical way of identifying publication bias
Publication bias means that research which shows a negative result, i.e., no statistical significance, is less likely to be published
Plot effect size against a measure of the study, and it if resembles a symmetric inverted funnel then no publication bias
No obvious publication bias in this study

14. Funnel plot

15. cohort studies vs. case series
Cohort study -- samples patients based on exposure and follows them over time to see if they develop the outcome
Sample on physical activity intervention and see if patients develop GDM
Allows for calculation of Relative Risk
Case series -- could sample patients based on both exposure and outcome, or based on outcome only
Hard or impossible to calculate Relative Risk

16. Study Advantages and limitations
High internal validity
Only included quality RCTs
Used physical activity-only interventions
Included studies from different countries
Publication bias not an issue
Limitations:
Small number of included studies (N=10)
Many of included studies with insignificant results