Serum Cystatin C is a potential biomarker for predicting amyotrophic lateral sclerosis survival.

OBJECTIVE: Currently, it is unclear whether serum Cystatin C can be used to evaluate the prognosis of ALS. We aim to study the relationship between serum Cystatin C and survival in ALS. METHODS: Sporadic ALS patients diagnosed at the Department of Neurology, the First Medical Center, and the Chinese PLA General Hospital from January 2016 to December 2019 were enrolled in this study. Experienced neurologists followed up the participants regularly every 6 months until January 2022. According to the levels of serum Cystatin C, the participants were divided into high and low Cystatin C levels groups. The comparison between groups was performed with parametric or non-parametric test. Kaplan-Meier method and Cox regression model were used to calculate survival analysis. RESULTS: Three hundred fifty-six sporadic ALS patients were enrolled in this study, including 203 males and 153 females. Among all ALS patients, 26 cases (7.3%) were lost to follow-up, 226 cases (63.5%) died, and 104 cases (29.2%) were still alive at the last follow-up. The median survival time of all ALS patients was 42.0 months. Patients with high Cystatin C levels had shorter median survival than those with lower Cystatin C levels (38.0 months vs. 48.0 months, P = 2.58 × 10-4). In multivariate Cox regression analysis, onset form, age of onset, diagnostic delay, disease progression rate, creatinine, and serum Cystatin C levels were associated with ALS survival. CONCLUSIONS: Our study found that serum Cystatin C was associated with ALS survival, and serum Cystatin C level might be an independent predictor of ALS survival.