The measurement of NSE on day 2 among the entire cohort of patients as well as in the group of OHCA patients varied between patients who survived cardiac arrest with good and poor neurological outcomes: 21.45 ± 13.05 vs. 97.29 ± 67.79 μg/L (SMD = −2.88; 95% CI: −3.30 to −2.46; p < 0.001; Figure 5) and 23.09 ± 14.45 vs. 112.01 ± 70.53 μg/L (SMD = −3.39; 95% CI: −4.08 to −2.71; p < 0.001), respectively (Figure S4). This evidence concerns the gene ENO2 and cardiac arrest.