Our objective was to explore if creatine kinase (CK) levels correlate with survival in amyotrophic lateral sclerosis (ALS), and whether a correlation is independent of other well-studied predictors such as location of onset, gender, age, fat free mass, spasticity, cramps, and fasciculations. We analyzed data from 80 ALS patients from a 48-week non-interventional longitudinal multicenter nutrition study with long term follow-up. The overall mean CK was 214 ± 191.8 U/l (range 22-1992 U/l). Forty-five percent of patients had at least one high CK value (> 200 U/l), and about half maintained a high CK value, but there was no trend over the study period. Male gender and extremity onset were significantly associated with high CK. In univariate analysis, age, bioelectric impedance spectroscopy (BIS) fat free mass, spasticity, and fasciculations were not associated with CK level. There was an association between CK and muscle cramps (p < 0.001). In survival analysis, low CK (≤ 200 U/l) was associated with a longer overall survival (p = 0.02), when adjusting for location of onset, age, race, gender, BIS fat free mass, and study site. In conclusion, CK may be a useful marker for ALS survival, which has implications for clinical care and the design of future clinical trials.
Keywords: CK; amyotrophic lateral sclerosis; biomarker; cramps; fasciculations.