Risk score for predicting death, myocardial infarction, and stroke in patients with stable angina, based on a large randomised trial cohort of patients

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Appendix: examples of calculation of the risk score

Example 1 is a woman with stable angina aged 65, ejection fraction 55%, white blood cell count 6 giga/l, blood glucose 100 mg/dl (multiply by 0.0555 for mmol/l), serum creatinine 1.25 mg/dl (multiply by 88.4 for μmol/L) who is using one anti-anginal drug and a statin, and has never had a coronary angiogram. The other risk factors in Table 1 are absent. Using the coefficients in the table multiplied by 10, the score contributions are [(65-60)/10]´ 0.55´ 10 or 2.75 for age, [(60-55)/5]´ 0.17´ 10 or 1.7 for ejection fraction, and (6-5)´ 0.068´ 10 or 0.68 for white blood cell count. Glucose is not above the limit of 100 mg/dl and therefore doesn’t contribute to the score. For creatinine, add [(1.25-1.15)/0.1]´ 0.078´ 10 or 0.78. For coronary angiogram never done add 0.11´ 10 or 1.1. For the use of one anti-anginal drug add 0.13´ 10 or 1.3 to the score. Summing these yields a total score of 8.31, which translates (S-shaped curve, right vertical axis in Figure 1) to a 4% chance of death, myocardial infarction, or disabling stroke in the next five years.

Example 2 is an otherwise similar patient who smokes, has at least one attack of angina per week, has a systolic blood pressure over 155 mm Hg, uses one additional anti-anginal drug, has a history of myocardial infarction and is a man. As shown in Table 1 this adds (0.60+0.22+0.21+0.13+0.14+0.16)´ 10 or 14.6 to the score of 8.31 for the above female patient. According to Figure 1, this patient’s total score of 22.91 implies a 16% chance of death, myocardial infarction, or disabling stroke in five years.

Example 3, if the patient in example 2 also had non-insulin dependent diabetes with a blood glucose of 200 mg/dl, a further 0.13´ 10 for the presence of diabetes and [(200-100)/10]´ 0.032´ 10 or 3.2 for blood glucose must be added. The total score of 22.91+1.3+3.2 or 27.41 translates (see Figure 1) to a 24% chance of death, myocardial infarction or disabling stroke in five years.