Risk of age older than 65 years for 30-day cardiac complication may be comparable to low-to-moderate risk according to revised cardiac risk index in non-cardiac surgery

Revised cardiac risk index (RCRI) is widely used for surgical patients without containing age as a risk factor. We investigated age older than 65 years with respect to low-to-moderate risk of RCRI. From January 2011 to June 2019, a total of 203,787 consecutive adult patients underwent non-cardiac surgery at our institution. After excluding high-risk patients defined as RCRI score > 2, we stratified the patients into four groups according to RCRI and age (A: age < 65 with RCRI < 2, [n = 148,288], B: age ≥ 65 with RCRI < 2, [n = 42,841], C: age < 65 with RCRI = 2, [n = 5,271], and D: age ≥ 65 with RCRI = 2, [n = 5,698]). Incidence of major cardiac complication defined as a composite of cardiac death, cardiac arrest and myocardial infarction was compared. After excluding 1,689 patients with high risk (defined as RCRI score > 2), 202,098 patients were enrolled. The incidence with 95% confidence interval of major cardiac complication for A, B, C, and D groups was 0.3% (0.2-0.3), 1.1% (1.0-1.2), 1.8% (1.6-1.8), and 3.1% (2.6-3.6), respectively. In a direct comparison between B and C groups, old patients with RCRI < 2 showed a significantly lower risk compared to younger patients with RCRI = 2 (odd ratio, 0.62; 95% confidence interval, 0.50-0.78; p < 0.001). In non-cardiac surgery, the risk of age older than 65 years was shown to be comparable with low-to-moderate risk according to RCRI.