Serum LDH and its isoenzymes (LDH2 and LDH5) associated with predictive value for refractory mycoplasma pneumoniae pneumonia in children

Abstract Objectives To contrast the level of lactate dehydrogenase (LDH) and its isoenzymes between general mycoplasma pneumoniae pneumonia (GMPP) and refractory mycoplasma pneumoniae pneumonia (RMPP) groups and to investigate their predictive value for RMPP in children. Methods A total of 160 children with GMPP and 100 children with RMPP were enrolled from August 2022 to April 2023 in our hospital. Serum LDH and its isoenzymes levels were assessed between the two groups. LDH and its isoenzymes were entered into multivariate logistic regression analysis to identify risk factors for RMPP, and variables with significance were used to analyze their diagnostic values for RMPP. ROC curves were drawn, and the AUC was calculated, with sensitivity and specificity obtained. Results Children with RMPP displayed more blatant inflammatory responses as well as more alarming imaging findings compared to those with GMPP. The levels of serum LDH and its isoenzymes in children with RMPP were significantly higher than those in children with GMPP. In the multivariate logistic regression analysis, LDH (OR=1.02, p<0.001), LDH2 (OR=1.05, p=0.010) and LDH5 (OR=1.04, p˂0.001) showed statistically significant differences. When the cut-off values were 372.5, 97.46, and 49.29 U/L respectively, the AUCs of LDH (sensitivity=0.80, specificity=0.89), LDH2 (sensitivity=0.83, specificity=0.71), and LDH5 (sensitivity=0.82, specificity=0.72) predicting RMPP were 0.91, 0.81, and 0.82, respectively. The AUC of [LDH + LDH5] (0.92) was the highest. Conclusions Serum LDH, LDH2, and LDH5 have good diagnostic values for RMPP and possess the potential to be biological markers in children with RMPP. And the predictive value is higher when used in combination.