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Centre for Evidence-
Based Medicine

Completed Therapy Worksheet for EBM in Developing Countries


ISIS-2 (Second International Study of Infarct Survival) Collaborative Group. Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17187 cases of suspected acute myocardial infarction: ISIS-2. Lancet 1988; ii:349-360.

Appraising an Article on Claims of Effectiveness

Are the results valid?

  1. Was the assignment of patients to treatments randomized?
    YES. See p. 349, title and under Summary, "17187 were randomized with placebo control…" Details are in p. 350, under Randomisation.
  2. Was follow-up adequate?
    YES. See p. 351, under Follow-up, "the completeness of follow-up is 99% to discharge, 97% to week 5."
  3. Were patients analyzed in the groups to which they were randomized?
    YES. See p. 350, under Randomisation, "whether or not the treatment in the pack was actually given, patients remained in their originally allocated group for an 'intention-to-treat' analysis."
  4. Were the patients, health workers, and study personnel blind to treatment?
    YES. See p. 350, under Treatment, "half of the patients were allocated randomly to receive streptokinase and half to receive matching placebo."
  5. Were the groups similar at the start of the trial?
    YES. See p. 352, under Results, "this large size ensured good balance between the treatment groups for the main pre-randomization features that were measured and should do likewise for those that were not."
  6. Aside from the experimental intervention, were the groups treated equally?
    YES. See p. 350, under Treatment, "in all other respects, physicians were free to use whatever additional therapy they considered necessary."

What are the results?

  1. How large was the treatment effect?
    See p. 352, Results. See p. 355, figure 2.
    Outcome Streptokinase Placebo RR RRR ARR NNT
    Vascular Mortality EER = 791/8592
    EER = 9.2%
    CER = 1029/8595
    CER = 12.0%
    0.77 (77%) 0.23 (23%) 0.028 (2.8%) 36
  2. How precise was the estimate of treatment effect?
    Vascular Deaths

    0.77[95% CI (0.70, 0.84)]

Will the results help me in caring for my patients?

  1. Can the results be applied to my patient care?
    See Applicability Worksheet.
  2. Were all clinically important outcomes considered?
  3. Are the likely treatment benefits worth the potential harms and costs?
    See Applicability Worksheet

Continue to completed applicability worksheet