Serum creatine kinase dynamics in amyotrophic lateral sclerosis: Predictive role of male sex, limb onset, and intermediate disease duration for stratified monitoring.

Objective: To investigate serum creatine kinase (CK) levels in amyotrophic lateral sclerosis (ALS) patients and their associations with disease characteristics, exploring its utility as a biomarker for disease progression.

Methods: This retrospective study included 81 definitive ALS patients and 99 matched controls. Serum CK levels were analyzed against sex, age, onset site, disease duration, and ALSFRS-R scores using Mann-Whitney U tests, Kruskal-Wallis tests, and multivariate regression.

Results: ALS patients exhibited significantly elevated CK levels compared to controls (233.92 ± 216.91 vs. 101.81 ± 34.28 IU/L, P < 0.05), with 65.43 % exceeding gender-specific ranges. Multivariate analysis identified male sex (β = 0.32, 95 % CI: 0.21-0.43; P < 0.05), limb onset (vs. bulbar: β = 0.41, 95 % CI: 0.29-0.53; P < 0.05), and intermediate disease duration (1-3 years: β = 0.32, P < 0.05) as independent predictors. CK levels peaked in limb-onset patients (lower limb: 342.40 ± 283.53 IU/L vs. bulbar: 96.20 ± 49.39 IU/L; P < 0.05). Higher CK was associated with moderate disease severity (ALSFRS-R 36-40 vs. ≤ 35: P < 0.05).

Conclusions: Serum CK elevation in ALS is strongly linked to male sex, limb onset, and intermediate disease duration (1-3 years), though long-duration cases (>3 years) were underrepresented (n = 4). These findings highlight CK's potential as a cost-effective biomarker for personalized monitoring, particularly in limb-onset males with moderate functional impairment. Further validation in larger cohorts is warranted.