To investigate the changes of serum ferritin (SF) and lactate dehydrogenase (LDH) expression of children with refractory Mycoplasma pneumonia (RMPP) and their prognostic value.

From October 2014 to October 2018, a total of 94 children with RMPP hospitalized in Hengshui People’s Hospital were collected as RMPP group, while children with Mycoplasma pneumoniae pneumonia (MPP) were selected as MPP group (60 cases) and healthy children of physical examination as control group (60 cases). The children in RMPP group were divided into death group (43 cases) and survival group (51 cases) according whether survived. The levels of SF and LDH of children in RMPP group, MPP group and control group were detected, and the correlations between SF, LDH and prognosis of RMPP group were analyzed, respectively. The prognosis of cases in RMPP group was effectively evaluated by Spearman rank correlation analysis.

The level of LDH in peripheral blood of children in RMPP group [(438.3 ± 18.5) IU/L] was significant higher than those of children in MPP group [(254.3 ± 21.8) IU/L] and control group [(136.8 ± 13.1)] IU/L, with significant differences (t = 8.7, P = 0.001; t = 19.1, P = 0.001). The level of SF in peripheral blood of children in RMPP group [(412.1 ± 20.6) ng/ml] was significantly higher than those of MPP group [(120.7 ± 13.3) ng/ml] and control group [(96.9 ± 11.5] ng/ml), with significant differences (t = 15.1, P = 0.001; t = 18.4, P = 0.001). Compared with RMPP children in survival group, levels of LDH [(473.2 ± 23.2) IU/L vs. (416.4 ± 19.1) IU/L] and SF [(445.2 ± 20.1) ng/ml vs. (396.2 ± 17.6) ng/ml] increased significantly of death group, with significant differences (t = 16.527, P = 0.037; t = 19.845, P = 0.015). The levels of LDH and SF of children with RMPP in survival group were significantly higher than those of death group, with significant differences (t = 16.527, P = 0.037; t = 19.845, P = 0.015). The AUC (0.8) of LDH was larger than that of SF (0.7), with significant difference (χ² = 5.735, P = 0.03). The sensitivity of LDH combined with SF detection (90.3%) was higher than those of LDH detection (82.6%) and SF detection (79.6%), with significant differences (χ² = 5.292, P = 0.016; χ² = 5.369, P = 0.024). The specificity of LDH combined with SF detection (88.4%) was higher than LDH detection (81.9%) and SF detection (81.7%), with significant differences (χ² = 6.408, P = 0.011; χ² = 6.278, P = 0.032). Spearman rank correlation analysis showed positive correlations between levels of LDH, SF and prognosis of RMPP children (r = 2.162, P = 0.015; r = 1.485, P = 0.022).

The levels of LDH and SF of RMPP children were significantly increased compared with healthy children and MPP children, which were closely related to the prognosis of children; the higher the levels of LDH and SF, the better the prognosis of children.