Serum Lactate Dehydrogenase Level As a Predictor Of Survival For Patients With Acute Exacerbation of Idiopathic Interstitial Pneumonias Undergoing Polymyxin B-Immobilized Fiber Column-Direct Hemoperfusion

BackgroundAcute exacerbation of chronic fibrosing idiopathic interstitial pneumonias (AE-IIPs) is known to be associated with a poor prognosis. In Japan, polymyxin B-immobilized fiber column-direct hemoperfusion (PMX-DHP) therapy is often used along with corticosteroids for the treatment of patients with AE-IIPs. However, the serum marker that predicts treatment response to PMX-DHP is still unknown. Our aim was to evaluate the serum marker that predicts the outcome in patients with AE-IIPs undergoing PMX-DHP therapy.MethodsWe retrospectively collected the medical records of 104 patients who developed AE-IIPs for the first time and visited Juntendo University Hospital between April 2009 and July 2020. Among these patients, 33 patients who received PMX-DHP were identified. Among the patients who received PMX-DHP, 18 patients who survived for over 30 days since the initiation of PMX-DHP therapy were classified into the “survival group,” and 15 patients who succumbed to the condition in less than 30 days were categorized into the “non-survival group.” We evaluated data on the patients’ background, survival, and differences in the serum markers associated with AE-IIPs and in oxygenation markers between the groups.ResultsAmong patient characteristics, median forced vital capacity was significantly higher in the survival group than in the non-survival group. Among serum markers, 7 days after the initiation of PMX-DHP therapy, serum lactate dehydrogenase (LDH) levels, white blood cell counts, and D-dimer levels were significantly higher and serum lymphocyte count was significantly lower in the non-survival group than in the survival group. PaO2/FiO2 ratio (P/F ratio) and alveolar-arterial oxygen difference (Aa-DO2) were significantly different between the two groups. The changes in LDH level (ΔLDH), P/F ratio, and Aa-DO2 were significantly different from day 1 to 7 days after the initiation of PMX-DHP between the two groups. Multivariate analysis revealed that ΔLDH was the only risk factor associated with poor prognosis. The cut-off value of ΔLDH was calculated as −8. The median survival time (MST) was significantly longer in patients with low ΔLDH values (<−8) than in those with high ΔLDH values (>−8).ConclusionsChanges in serum LDH levels are reasonable markers for evaluating the prognosis of PMX-DHP therapy.