Coronary heart disease: several diagnostic tests are cost-effective.

Clinical bottom line (level 1a)

  1. In patients with suspected coronary artery disease immediate angiography, SPECT, PET, echocardiography, planar thallium imaging and exercise echocardiography are all of about the same cost-effectiveness.
  2. Positron emission tomography is more expensive than the other tests, but also has a higher sensitivity and specificity.
Garber and Solomon: Annals of Internal Medicine 1999; 130 (9): 719-728
Expires March 2003

The study

Decision analysis model.
Setting: multicentre

Data was found on patients with a history of chest pain and a 25-75% pretest probability of coronary disease by searching MEDLINE for all relevant English-language articles of the diagnostic tests: exercise electrocardiography, planar thallium imaging, single-photon emission computed tomography (SPECT), echocardiography and positron emission tomography (PET), compared to coronary angiography. The search strategy was: 'diagnostic test AND cardiac AND sensitivity'. Bibliographies of review articles were also searched. Sensitivities of the tests were estimated from the articles. 27 articles were included.

  • Viewpoint: Societal
  • Benefit assessment: Quality-adjusted life years
  • Resources and costs: The costs of the initial tests and of subsequent management contribute to differences in the total costs of each testing strategy. Test accuracy influences management: false positives lead to unnecessary angiography and false negatives reduce the immediate cost of surgery. Medicare payments based on the national average relative value units for 1996 are the principal source of outpatient and diagnostic costs. Costs used were: PET- $1500; SPECT- $475; stress echocardiography- $265; plana thallium imaging- $221; exercise electrocardiography- $110; coronary artery bypass surgery, 1 and 2 vessel- $32,390; coronary artery bypass surgery, 3 vessels and left main- $32,824; MI, single admission- $7415; cardiac catheterisation with angiography- $1810; percutaneous transluminal coronary angiography- $11,685. QALYs and the present value of future health expenditures in 1996 US dollars were calculated by using an inflation-adjusted interest rate of 3%.
  • Sensitivity analysis: A sensitivity analysis was performed for the cost of positron emission tomography cost, between the cost of $750 to $1500, and for age, sex, pretest probability, test indeterminacy and severity of disease.

    • The evidence

    intervention cost
    angiography in men $34, 661
    ( 12.259 QALYs )
    angiography for women $41, 101
    ( 14.137 QALYs )
    positron emission tomography in men $35, 093
    ( 12.255 QALYs )
    positron emission tomography in women $41, 551
    ( 14.134 QALYs )
    single-photon emission computed tomography in men $34, 047
    ( 12.253 QALYs )
    single-photon emission computed tomography in women $40, 510
    ( 14.132 QALYs )
    echocardiography in men $33, 341
    ( 12.244 QALYs )
    echocardiography in women $39, 835
    ( 14.125 QALYs )
    planar thallium imaging in men $33, 467
    ( 12.243 QALYs )
    planar thallium imaging in women $39, 964
    ( 14.125 QALYs )
    exercise electrocardiography in men $33, 281
    ( 12.234 QALYs )
    exercise electrocardiography in women $39, 815
    ( 14.119 QALYs )

    Effect of sensitivity analysis: Qualitative findings varied little with age, sex, pretest probability or test indeterminacy rate. Results varied most with sensitivity to severe coronary disease.
    • Planar thallium imaging: sensitivity 79%; specificity 73%.
    • SPECT: sensitivity 88%; specificity 77%.
    • Echocardiography: sensitivity 76%; specificity 88%.
    • PET: sensitivity 91%; specificity 82%.
    • Exercise electrocardiography: 68%; specificity 77%.

    Comments

    1. The authors did not comment on the socioeconomic aspects of simplicity, safety and availability, which are the fundamental advantages of exercise-electrocardiography
    2. The widespread availability of exercise-ECG must be balanced against the highly specialist nature of SPECT and PET imaging.

    Citation

    1. Garber AM, and Solomon NA: Cost-effectiveness of alternative test strategies for the diagnosis of coronary artery disease. Annals of Internal Medicine 1999; 130 (9): 719-728
    Contributor: Clare Wotton and Musab Hayatli, January 2000
    Reviewer: Andreas Michaelides

    Clinical Question.
    Patient coronary heart disease
    Intervention or Exposure various diagnostic tests
    Comparison other diagnostic tests
    Outcome ability to diagnose and cost-effectiveness