Left-Digit Bias and CABG

This study of Medicare beneficiaries evaluated how often CABG was performed related to narrow intervals around a patient's birthday. Those who were seen just prior to their 80th birthday (thus 79 years old, representing left-digit bias) were abouth 30% more likely to undergo CABG than those who were seen just after their birthday (thus 80 years old). Similar findings were not evident for other ages in the same range (e.g. 77, 78, 79, 81, 82, 83). For comparison, mortality after MI was unrelated to the interval surrounding an individual's 80th birthday. The findings support the presence of left-digit bias in clinical decision-making.