course: research in biomedicine and health iii lab 3: looking for evidence

Course: Research in Biomedicine and Health IIILab 3: Looking for evidence

EBM steps◦Step 1: Formulating questions that can be

answered◦Step 2: Finding best evidence◦Step 3: Quick critical assessment of the

evidence◦Step 4: Applying evidence◦Step 5: Assessing effectiveness and

efficiency of the process

Be precise!

Kew words for database search

PPatient,

problem

Iintervention

CComparison

(not always)

OOutcome

TType of

study

Metaanalysis

Systematic review

RCT

Cohort study

Case-control study

Case series/case reports PubMed (MEDLINE)“AND” case report

PubMed (MEDLINE)“AND” case control study

PubMed (MEDLINE)“AND” cohort study

ACP Journal Club / Cochrane Central Register of Controlled Trials

Pubmed (MEDLINE) Clinical Queries (Therapy)

ACP Journal Club / Cochrane Database of Systematic Reviews

Pubmed (MEDLINE) Clinical Queries (Systematic Reviews)

ACP Journal Club / Cochrane Database of Systematic Reviews

Pubmed (MEDLINE) “AND” meta-analysis

65 year-old patient is recovering from a stroke. He has narrowing of the left carotid artery confirmed by US.

Would therapy with acetyl-salicilic acid decrease the risk of another stroke?

Type of question: ◦ Therapy/prevention

Study design: ◦ RCT/systematic review

Concepts: ◦ stroke◦ Acetyl-salicilic acid (aspirin)◦ Systematic reviews or randomized controlled studies

Example – What needs to be determined

First search Cochrane Database of Systematic Reviews.

CDSR can be accessed via OvidSP – link on the web-site of the School’s library.

Choose the database on the front page.

• Choose “Advanced Search” and check that the search is by “Keywords”

• Enter only one term and start “Search”• Enter the second key word and “Search”• Click Search History• If you are using more keywords, link them with OR and

then link their sets with AND• Limit the search to “Full Systematic Reviews”• Check the results

• If you want to look for a RCT, choose PubMed or Ovid MEDLINE

• PubMed has special interface for clinical questions

• At the start page of PubMeda click on Clinical Queries (below PubMed Tools)

• Enter keywords, e.g.:probiotics irritable bowel syndrome

• Choose the category for your search (e.g. Therapy) i search precision (Broad/Narrow)

• Start the search

In the column Clinical Study Categories click on “See all” below search results

When the search results are displayed, click Limits Choose Randomized Controlled Trial under Type of

Article

Define a search strategy according to your PICO(T) questions from day 2.

Your patient has 45 years and complains of frequent migraine headaches. She tried different medications but is afraid of side-effects. She is healthy, except for the history of asthma during childhood. She read in a magazine about bio-feedback and using relaxation as a treatment for migraine. She is asking you for advice.

Your patient has 56 years. He was released from a hospital 6 weeks before, after he was admitted because of slight heart failure. He comes to you for a check up. He feels well but sometime fells that his heart “misses a beat”. ECG confirms atrial fibrillation. The patient wanders if this arrythmia is dangerous and needs a treatment. Preventive anticoagulant warfarine therapy is one possibility but carries a small risk of stroke because of bleeding. You want to check if the risks of such therapy outweigh its benefits.

Parents of your patient want to sue you as her family physician because of malpractice. Their 22 year-old daughter suddenly fainted at home. They took her to ER, where she was pronounced dead on arrival. The ER doctor mentioned a blood clot in her lungs. Local organization “Parents against contraceptives industry” is talking the parents into suing the producer and you because you prescribed the contraceptive about a year ago. You want to check the association between oral contraceptives and thromboembolism.

Your patient takes nicotine replacement therapy as smoking cessation treatment. His friends suggested acupuncture as a quicker therapy. You want to check if this is true.

Your friend asks you if there is evidence for the use of feverfew in the therapy of migraine.

Your patient is middle-aged and is a frequent airplane traveler. He is worried because of the risk of deep vein thrombosis during flight. You want to check whether compression socks would be useful in preventing the problem.