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Centre for Evidence-
Based Medicine

Harm: Clinical Scenario

You have been called to a meeting with the Health Authority Chief Executive to discuss concerns about long term effects of the oral contraceptive pill, particularly following a recent national pill scare. You formulate the question, in women using oral contraceptives: "What is the risk of death?"

Following the local librarian's advice, you search MEDLINE using the following text words (cohort$ and oral contraceptive$ and relative risk $).tw for the best quality cohort study you can find that specifically addresses the question of safety of the pill. Amongst a large number of much smaller studies using poorer quality designs, one recent study stands out in both size and duration ( BMJ 1999;318:96-100 ) which you download from the British Medical Journal's free website: http://www.bmj.com/.

Read the article and decide:

  1. Are the results of this harm study valid?
  2. Are the results of this harm study important?
  3. Should these valid, important results of this study about a potentially harmful treatment change the treatment of your population?

Continue to completed worksheet