The serum creatinine to cystatin C ratio predicts the risk of acute exacerbation of chronic obstructive pulmonary disease

Abstract

The purpose of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) treatment is to minimize the negative impact of the current exacerbation and to prevent the development of subsequent events. Therefore, it is important to identify readily available serological indicators during hospital admission to assess the prognosis of patients with AECOPD. All patients hospitalized in a Department of Respiratory and Critical Care Medicine of tertiary care hospital between January 2021 and December 2021 for AECOPD were analyzed using univariate correlations and binary logistic regression analysis with 2 models for associations between demographic, clinical, and laboratory features and AECOPD risk. The ratio of creatinine to cystatin C (Cre/Cys C) ratio was significantly associated with age (r=-0.206, P=.000), weight (R=0.331, P=.000), body mass index (BMI) (R=0.133, P=.007), and forced vital capacity (FVC)% predicted (R=0.130, P=.009). Multiple regression was performed to predict the Cre/Cys C ratio from age, weight, BMI, forced expiratory volume during 1 second/FVC ratio, and FVC% predicted FABP-4, with F (5, 405)=24.571, P=.000, R2=0.233. The results showed that the most significant predictors of the Cre/Cys C ratio were age (P=.007), weight (P=.000), BMI (P=.000), and predicted forced expiratory volume during 1 second (P=.000). Multivariate analysis was performed to determine whether the Cre/Cys C ratio was a predictor of AECOPD risk. Model 1 showed that a low Cre/Cys C ratio was associated with an increased hospital length of stay (odds ratio: -0.114, 95% confidence interval: -0.061 to -0.005) and admission to the intensive care unit (odds ratio: 0.951, 95% confidence interval: 0.907-0.996). After adjustment for potential confounding factors, model 2 showed that a low Cre/Cys C ratio was not independently associated with AECOPD risk. The present study indicated that the Cre/Cys C ratio is an easy, cheap, repeatable, and promising tool that allows us to evaluate the risk of AECOPD using serum markers. A low Cre/Cys C ratio was associated with a prolonged hospital length of stay and admission to the intensive care unit in AECOPD patients. However, the associations were not independent.