Prognostic role of creatine kinase-MB in elderly patients with sepsis

Although creatine kinase-MB (CK-MB) is a well-established predictor of myocardial infarction, emerging evidence suggests it has prognostic value in various infections; however, its role in sepsis remains unexplored. This study aims to investigate the predictive value of CK-MB for short-term mortality in elderly patients with sepsis.

A total of 1752 patients aged ≥ 60 with sepsis were included and divided into four groups according to the quartiles of CK-MB within 24 h after ICU admission: < 6.6 (n = 435), 6.6-10.9 (n = 440), 10.9-18.5 (n = 435) and ≥ 18.5 (n = 442). Multivariate analysis was conducted to investigate the association of CK-MB with 28-day mortality and identify the risk factors for CK-MB elevation.

Both in-hospital (39.1% vs 43.0% vs 51.3% vs 60.4%, P < 0.001) and 28-day mortality (24.7% vs 30.2% vs 40.8% vs 56.3%, P < 0.001) rose progressively with increasing CK-MB levels. Multivariate Cox regression analysis confirmed log₁₀ CK-MB (HR=2.32, P < 0.001) and elevated CK-MB (>25U/L; HR=1.92, P<0.001) as independent predictors of 28-day mortality. The Receiver Operation Characteristic curve analysis demonstrated comparable predictive performance between CK-MB and lactic acid for 28-day mortality (Area under the curve: 0.650 vs. 0.649, P = 0.962). Adding CK-MB to APACHE II improved mortality prediction of sepsis (Categorical Net Reclassification Index = 2.5%, P = 0.038). Patients with both CK-MB > 25 U/L and lactate > 2 mmol/L had the highest mortality. Liver disease, renal impairment, vasopressor use, and hyperlactatemia were independent risk factors for elevated CK-MB.

In elderly patients with sepsis, elevated CK-MB level measured upon ICU admission was associated with increased 28-day mortality. The combination of CK-MB and lactic acid levels may enhance risk stratification in sepsis patients.