Serum creatinine/cystatin C ratio as a surrogate marker for sarcopenia in patients with chronic obstructive pulmonary disease

Clin Nutr. 2021 Mar;40(3):1274-1280. doi: 10.1016/j.clnu.2020.08.010. Epub 2020 Aug 19.

Abstract

Background & aims: Sarcopenia is common in patients with chronic obstructive pulmonary disease (COPD). Serum creatinine/cystatin C (Cr/CysC) ratio has attracted attention as a surrogate marker for sarcopenia but has not been adequately studied in patients with COPD. Thus, the purpose of this study was to investigate the validity of serum Cr/CysC ratio as a predictor of sarcopenia, evaluate a statistical cut-off value, and assess the relationship between Cr/CysC ratio and clinical factors.

Methods: In this prospective observational study, we enrolled 234 male outpatients with COPD. We determined the relevance of serum Cr/CysC ratio as a surrogate maker for sarcopenia by comparing it with various biomarkers and prospectively investigated the relationship of Cr/CysC ratio with the annual exacerbation rate.

Results: Serum Cr/CysC was significantly correlated with handgrip strength (r = 0.53, P < 0.01) and muscle mass (r = 0.44, P < 0.01). The area under the curve for sarcopenia was significantly larger for serum Cr/CysC ratio than for other biomarkers (Cr/CysC: 0.87, CysC: 0.63, Cr: 0.61, albumin: 0.57). Multivariate analysis showed no significant difference in the frequency of acute exacerbations between patients in the low- and high-Cr/CysC group, defined by the cutoff value 0.71; however, the frequency of severe acute exacerbations was significantly higher in the low-Cr/CysC group.

Conclusion: Serum Cr/CysC ratio can be used accurately, inexpensively, and easily to evaluate sarcopenia in male patients with COPD. Our study shows that patients with Cr/CysC below 0.71 have poor physical clinical factors and are at high risk of severe acute COPD exacerbations.

Keywords: Acute exacerbation; Chronic obstructive pulmonary disease; Creatinine; Cystatin C; Sarcopenia.

Publication types

  • Comparative Study
  • Observational Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers / blood*
  • Creatinine / blood*
  • Cystatin C / blood*
  • Hand Strength
  • Humans
  • Male
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive / blood*
  • Reproducibility of Results
  • Sarcopenia / blood*
  • Sarcopenia / epidemiology
  • Severity of Illness Index

Substances

  • Biomarkers
  • Cystatin C
  • Creatinine