The evidence

Myocardial infarction: tissue plasminogen activator was cost-effective.

Clinical bottom line (level 1b)

  1. In patients who had an MI, tissue plasminogen activator was more expensive than streptokinase, but improves life expectancy.
  2. Tissue plasminogen activator was more cost-effective in patients over 75 years old with a life expectancy of 5 years, than in patients 75 years or younger with the same life expectancy.
  3. Tissue plasminogen activator was more cost-effective in patients with an anterior MI, than those with an inferior MI.
Kalish et al: Journal of General Internal Medicine 1995; 10: 321-330
Expires March 2003

The study

Decision analysis model
Setting: general hospital, USA

Patients with acute myocardial infarction who were candidates for thrombolytic therapy and who presented within six hours of symptom onset, were included. It is not clear where the data is from, but probabilities of bad outcomes are derived from the GUSTO trial.

  • Viewpoint: health care system
  • Benefit assessment: 30 day and one year mortality, disabling and nondisabling stroke, reinfarction, haemorrhage, hypotension, anaphylaxis and long-term medical costs.
  • Resources and costs: Utilities are taken from a subset of patients in the GISSI-2 trial. Thrombolytic therapy cost $313 for streptokinase (SK) and $2,244 for tissue plasminogen activator (tPA), according to the costs at the hospital where the study was set and Medicare diagnosis-related group data. The costs are the incremental costs of differential complication rates, as hospitalisation for uncomplicated myocardial infarction is the same for all patients. Costs associated with reinfarction were a half of the cost of hospitalisation for uncomplicated MI. Professional fees were also included. The incremental costs associated with death from MI were estimated as the difference between fatal and uncomplicated MIs. Cost of stroke and coronary artery bypass grafting were included. Cost of serious haemorrhage treatment was previously estimated as $1,868 and for hypotension and anaphylaxis was $500 for each episode. The annual cost of managing coronary artery disease has previously been reported to be $2,452 per year, using data derived from the Coronary Heart Disease Policy Model. Long-term care costs associated with treatment of disabling stroke were estimated to be $29, 293 per year, based on national data. Costs are expressed as 1992 dollars, and all costs and QALYs are discounted at a rate of 5% per year.
  • Sensitivity analysis: Mortality rate with tPA was varied between 8.0% and 9.75% (with 9.0% being the baseline: 10.1% with SK); cost of tPA was varied between $500 and $5,000 ($2,216 baseline: $313 SK); life expectancy after MI varied between 3 and 16 years (baseline 14.6 years); stroke rate with tPA varied between 0.5% and 1.5% (baseline 0.9%: 0.*% with SK); reinfarction rate varied between 3.0% and 5.0% (baseline 4.0%: 3.7% with SK).

    • The evidence

    intervention cost
    streptokinase $27, 164
    ( life expectancy 8.842 QALYs )
    tissue plasminogen activator $29, 699
    ( life expectancy 8.926 QALYs )
    incremental cost-effectiveness of tPA ($/QALY) in patients <75 years $60,000
    ( life expectancy 5 years )
    incremental cost-effectiveness of tPA in > or = 75's $48, 800
    ( life expectancy 5 years )
    cost-effectiveness of tPA in anterior MI $16, 300
    ( per QALY )
    cost-effectiveness of tPA in inferior MI $53, 800
    ( per QALY )

    Effect of sensitivity analysis: As the mortality with tPA increases, the cost-effectiveness worsens. The model was also sensitive to cost of thrombolytic therapy and life expectancy after MI. Changes in the rates of thrombolysis-related strokes and reinfarctions had only a modest effect.
    • Figures were based on 30 day mortality from the GUSTO trial, and the baseline cost for all ages was $30, 300 per QALY.

    Citation

    1. Kalish SC, Gurwitz JH, Krumholz HM, et al: A cost-effectiveness model of thrombolytic therapy for acute myocardial infarction. Journal of General Internal Medicine 1995; 10: 321-330
    Contributor: Clare Wotton and Bob Phillips, February 2000
    Reviewer:

    Clinical Question.
    Patient myocardial infarction
    Intervention or Exposure streptokinase
    Comparison tissue plasminogen activator
    Outcome cost-effectiveness
intervention cost
streptokinase $27, 164
( life expectancy 8.842 QALYs )
tissue plasminogen activator $29, 699
( life expectancy 8.926 QALYs )
incremental cost-effectiveness of tPA ($/QALY) in patients <75 years $60,000
( life expectancy 5 years )
incremental cost-effectiveness of tPA in > or = 75's $48, 800
( life expectancy 5 years )
cost-effectiveness of tPA in anterior MI $16, 300
( per QALY )
cost-effectiveness of tPA in inferior MI $53, 800
( per QALY )

Effect of sensitivity analysis: As the mortality with tPA increases, the cost-effectiveness worsens. The model was also sensitive to cost of thrombolytic therapy and life expectancy after MI. Changes in the rates of thrombolysis-related strokes and reinfarctions had only a modest effect.

Citation

  1. Kalish SC, Gurwitz JH, Krumholz HM, et al: A cost-effectiveness model of thrombolytic therapy for acute myocardial infarction. Journal of General Internal Medicine 1995; 10: 321-330
Contributor: Clare Wotton and Bob Phillips, February 2000
Reviewer:

Clinical Question.
Patient myocardial infarction
Intervention or Exposure streptokinase
Comparison tissue plasminogen activator
Outcome cost-effectiveness