We aimed to evaluate differences in serum lactate dehydrogenase (LDH) isoenzymes between patients hospitalized for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and other lower respiratory tract infections (LRTIs). Based on self-reported COPD diagnosis, 71 participants were divided into AECOPD (n = 38, 29 males, mean age 70.5 years) and LRTI (n = 33, 12 males, mean age 70.4 years) groups. Information on demographics, comorbidities, and COPD severity markers, as well as arterial blood gases and laboratory data were collected, while serum LDH electrophoresis was performed to examine the LDH isoenzymes. Adjusting for sex, age, comorbidities, degree of hypoxemia, inflammation markers, muscle and myocardial enzymes, and total serum LDH, the mean differences (95 % confidence intervals) in the ratios of serum LDH isoenzymes to total serum LDH between groups (LDHx_AECOPD − LDHx_LRTI) were statistically significant for LDH1 [4.9 (1.4 to 8.3)], LDH2 [3.0 (0.1 to 5.8)], LDH3 [−4.3 (−6.3 to −2.3)], and LDH4 [−3.2 (−4.9 to −1.5)]. A sum of LDH3 and LDH4 ratios below 29 % had the highest discriminative ability to classify a subject in the AECOPD group (AUC 0.841, sensitivity 76 %, specificity 87 %). Aerobic metabolic adaptive mechanisms in respiratory muscles during AECOPD could explain the above differences.

我们旨在评估因慢性阻塞性肺疾病急性加重 (AECOPD) 和其他下呼吸道感染 (LRTI) 住院的患者之间血清乳酸脱氢酶 (LDH) 同工酶的差异。根据自我报告的 COPD 诊断，71 名参与者被分为 AECOPD（n = 38，29 名男性，平均年龄 70.5 岁）和 LRTI（n = 33，12 名男性，平均年龄 70.4 岁）组。收集人口统计学、合并症和 COPD 严重程度标志物的信息，以及动脉血气和实验室数据，同时进行血清 LDH 电泳以检查 LDH 同工酶。调整性别、年龄、合并症、低氧血症程度、炎症标志物、肌肉和心肌酶以及总血清 LDH，_AECOPD - LDHx _LRTI ) 对 LDH1 [4.9 (1.4 至 8.3)]、LDH2 [3.0 (0.1 至 5.8)]、LDH3 [-4.3 (-6.3 至 -2.3)] 和 LDH4 [-3.2 (-4.9) 具有统计学意义到-1.5)]。LDH3 和 LDH4 比率之和低于 29% 具有对 AECOPD 组中的受试者进行分类的最高区分能力（AUC 0.841，敏感性 76%，特异性 87%）。AECOPD 期间呼吸肌的有氧代谢适应机制可以解释上述差异。