Background: Muscle atrophy is a major clinical feature of
chronic obstructive pulmonary disease (COPD), and it is
considered a strong predictor of mortality in COPD patients.
This study aimed to assess the use of serum
creatinine/serum Cystatin C ratio in the assessment of
muscle wasting and disease severity in stable COPD
patients. Methods: This case-control study included 70
COPD patients and 20 age and gender-matched healthy
controls. Pulmonary function tests, measurement of the
serum creatinine (Cr) and cystatin C (Cys-C) levels, chest
high-resolution CT images (HRCT) for the assessment of
low attenuation area percentage (LAA%) and Erector
Spinae muscle (ESM) thickness, routine laboratory
investigations and arterial blood gases (ABG), were done.
Results: There was a significant positive correlation
between serum cystatin c and severity of COPD and LAA%
but there was a significant negative correlation between
serum cystatin c and Erector Spinae muscle cross-sectional
area (ESMCSA), forced vital capacity %predicted (FVC%
predicted), forced expiratory volume in 1 second
(FEV1%predicted) FEV1/FVC%, and body mass index
(BMI). Moreover, there was a significant positive
correlation between creatinine/Cys C ratio and BMI,
ESMCSA, FVC% predicted, FEV1/ FVC % and FEV1%
predicted. The cut-off points of ESMCSA and Cr/Cys C for
severe COPD were 23.4 cm2 and 0.87 respectively. Conclusion: The present study
indicated that the Cr/Cys C ratio is an easy, inexpensive, repeatable, and promising tool
that allows us to evaluate muscle wasting in COPD patients using serum markers as there
is a positive correlation between the degree of muscle wasting and the severity of COPD.