1. “Reading and commenting papers” (Scientific English) Alexis Descatha INSERM, UMS UVSQ- Unité de pathologie professionnelle, Garches

2. Acknowledgments Descatha 2 Harvard School of Public Health Harvard Center for Population and Development Studies, L Berkman, E Sabbath

3. WHY and HOW Descatha 3 In the context of « Publish or Perish » and potential conflict of interest, be aware of limitations Read and understand original scientific papers (in English) By doing a structured summary (« abstract ») and Answering to questions 8 papers with corrections

4. Descatha/Davy method for summarizing an original paper Arthur Davy, Alexis Descatha UFR des sciences de la santé, Université de Versailles St Quentin

5. !Warning! Descatha 5

6. IMRaD Background (+/-) and objective (aim/goal) Methods population (sample), intervention (if applicable), exposure and outcome variables of interest, and analyses Results Details of sample Answer to the research question (quantitive) and side effects/ tolerance Conclusion = answer to the question PICO 6 Descatha

7. Descatha/Davy method TIME Reading Quick reading of title, questions, and the paper And the paper, highlighting in yellow the key sentences Drafting Take 3 « word tables» Cut and paste main sentences Writing Shorten the summary! Descatha 7

8. Advice Tense = past (present form only for evidence that everyone is agreed upon and future for perspectives) Don’t hesitate to use similar sentences, words … The corrector is not a native English speaker (try to do his best) Scoring / rating table +++ You can look for the abstract given by the authors, but … Training is the key ! Descatha 8

9. Vocabulary DESIGN++++ Observation Epidemiology+++ Cross sectional / case-control / cohort studies (+ review /meta-analysis/ case report…) Experimentation Clinical trials (randomized) Diagnostic studies (ie accuracy) Descatha 9

10. RCT Question is clear and very precise Method Design Sampling (including randomisation) => Flow chart Outcomes Number of subjects Analyses Results No difference between the two randomized groups Answer to the question Discussion Limitations, « so what » and perspectives Descatha 10

11. Accuracy in diagnosis Reliable test If repeated, similar results Valid and accurate: No false negative and no false positive => sensitivity/ specificity Practical considerations Screening vs. confirmatory testing Gold standard (but…) All same protocol, blindness Sensitivity, specificity, predictive values, likelihood ratio, ROC curves, AUC-DgOR… Descatha 11

12. Obervational study Aim and design (cf.) Inclusion criteria Exposure assessment, outcome Risk measurement (ratios and risks) Causality discussion and bias+++++ Descatha 12

13. Descatha 13 Design Experimentation (+/- randomization) OBSERVATION  Description= Prevalence (Incidence)  « Causation » (association )

14. Descatha 14 Causative studies Case control Cohort Inclusion of patients AND data Cross sectional Time Inclusion of patients Inclusion data (retrospectively) Inclusion of patients Inclusion data

15. Descatha 15 Design Experimentation (+/- randomization) OBSERVATION  Description= Prevalence (Incidence)  « Causation » (association )  cross-sectional: prevalence, association OR +/-  Cas control : prevalence, association OR  Cohort : incidence, association RR

16. Descatha 16 OR RR Disease +Disease -Total Exposedaba+b Not exposedcdc+d Totala+cb+da+b+c+d RR= [a/(a+b]/[c/c+d)], WITH 95% confidence interval OR= a*d/(b*c), with 95% confidence interval P RR (or OR) the CI do not include « 1 »

17. Statistically significant ? Descatha 17 1.5 2.0 2.5 0.8 2.4 4.0 1 1 1.0 1.4 1.8 1 OR/RR 95%CI CI95% 0.5 0.7 0.9 OR/RR 95%CI 1

18. Bias ? Selection bias Representativness Measurment bias case=case? / exposed = exposed? Confounding other factors not considered, that could explained the observed association Descatha 18

19. Vocabulary Sampling and intervention Design, observational/ experimental, longitudinal/cross-sectional, prospective/retrospective Participants: settings/Inclusion/ exclusion, case and controls, mono or multicenter (Matched?/paired) Blinding?/ Randomization/ Intention to treat / flow diagram… Measures of the diseases Prevalence/ incidence … Questionnaire, physical examination, laboratory/radiology/pathology findings (data sources) Descatha 19

20. Vocabulary Analyses Statistical power, number of subject (sample size ) Uni and Multivariate analyses (models) Measures of the effect Association / efficacy or tolerance P<0.05, statistical significance, statistical power Odds ratio, relative risk… Sensitivity, specificity, predictive values, likelihood ratio… Limitation and bias (selection, information, confounding => causation?) Generalizability and perspectives Descatha 20

21. Now it is your turn! Consort, Stard, Strobe statements Pubmed is helpful Internet +++ (most of the “LCA” books have a glossary, including translation) Descatha 21