medical literature: a quick guide

1. Medical literature: a quick guide

3. What is primary literature? Backbone of science Synopsis of lab and analytical work Always peer reviewed (we’ll discuss this shortly)

4. What is primary literature? Based on hypothetico-deductive method Form hypothesis and null hypothesis Derive if-then statements and test Goal: reject null hypothesis Another goal: support hypothesis!

5. What are type I and II errors? Type I error: accidentally reject null when you should have accepted it. Type II error: accidentally reject alternate hypothesis when you should have accepted it.

6. What is peer review?

7. What is peer review? Researchers in same topic area review and edit submitted works Works published only after editing and approval Quality control system Peer-reviewed papers are the most credible sources of information Almost all primary literature is peer-reviewed If it isn’t, consider the information twice!

8. How do I identify peer-reviewed journals? Look for contributing author instructions Look at first page of article for list of dates: Submitted Revised Accepted

11. What is secondary literature? AKA review papers Summary/synthesis of primary lit. in one topic area Addresses current research on a question Authors often write them to present new hypothesis before doing research Allows them to “scoop” other researchers Many studies weighed against each other Exhaustive evaluation Usually peer-reviewed

12. What is tertiary literature? Least likely of three types to be accurate Why? Articles usually aimed at people who are not experts on the subject Frequently made for the lay person Very common that writer has no background in topic area e.g. reporters

13. How do I know I’m looking at primary literature? Format Abstract Introduction Methods Double-blind is the gold standard Random sample, at least 20 subjects, much better if 100+ Results Conclusion (discussion) Usually peer-reviewed Authors credentials always identified

14. Where do I find primary literature? Journals covering narrow topic area J. of Orthopaedic and Sports Physical Therapy Postgraduate Medicine J. of Infectious Diseases Library—almost all primary lit. is by subscription only

18. How do I know I’m looking at secondary literature? A bit more general than primary lit. Usually longer, with very long citations section (sometimes into the hundreds!) Often with table of contents Title often includes phrases like… A review of… New ideas/insights/thoughts on… An update on… A history of… Advances in… Perspectives on… Methods section missing

22. Where do I find secondary literature? Library—same reason as for primary lit. Some review article appear in journals which mostly print primary lit. Others appear in review-exclusive journals Annual Review of Pharmacology Annual Review of Immunology Annual Review of Medicine Trends in molecular medicine Advances in oto-rhino-laryngology

23. How do I know I’m looking at tertiary literature? Very non-technical language Aimed at general audience No abstract, no citations If citations present, only a few and most often very general Shorter article Lacks technical information/discussion

25. Where do I find tertiary literature? Just about anywhere Newspapers Encyclopedias Textbooks Magazines Website summaries (e.g. government)

26. What about the Internet? All three type of literature here Use extreme caution! Anyone with a computer and Internet access can publish Many web resources not editor-verified Or peer-reviewed! Very often difficult to determine authorship If available, still may not list author’s credentials Money motivates persuasive articles The “virtual soapbox” Our product is a miracle, unbelievable results… Dates often not included You could be reading out-of-date information

28. What are clinical trials? Research studies involving people Prospective studies—yes Framingham Heart Study Retrospective studies—no Types of clinical trials Treatment trial Prevention trial Early-detection/screening trial Diagnostic trials

29. What are the different stages of clinical trials? Phase I 15-30 people Goals Find safe dosage Decide how to give agent Observe affects of agent on humans (side effects, etc.)

30. What are the different stages of clinical trials? Phase 2 About two-thirds of drugs make it this far < 100 people Drug tested for efficacy Control and placebo groups Usually double-blind experiment Also monitor safety

31. What are the different stages of clinical trials? Stage 3 100-thousands Demonstrates efficacy on large number of people Still monitoring efficacy and side effects Allows comparison of new approach/drug with old drugs/approaches Helps fine-tune drug dosages Can apply for FDA approval at end of trial

32. What are the different stages of clinical trials? Phase 4 Several hundred to several thousand Evaluate long-term safety and efficacy Drug/approach now in general use

33. It’s quiz time! Identify (not out loud!) whether each is primary, secondary or tertiary.