Serum lactate dehydrogenase as a prognostic marker for 90-day mortality in connective tissue disease patients receiving glucocorticoids and hospitalized with pneumonia: a cohort study
Cheng Xu, Lanling Liu, Yu Tian, Yuansheng Lin
Abstract
Elevated serum lactate dehydrogenase (LDH) levels have been associated with poor prognosis in various diseases. This study investigates the relationship between serum LDH levels and 90-day mortality in patients with connective tissue disease (CTD) receiving glucocorticoids and hospitalized with pneumonia. A total of 298 CTD patients were included in this study. The cohort was divided into three groups based on serum LDH levels (Group 1: < 246 U/L, 0% mortality; Group 2: 246-407 U/L, 26% mortality; Group 3: ≥ 407 U/L, 48% mortality). Clinical and laboratory data were analyzed to evaluate the association between LDH levels and 90-day mortality using Kaplan-Meier survival curves, Cox regression models, and subgroup analyses. Elevated LDH levels were significantly associated with increased mortality. The Kaplan-Meier survival analysis demonstrated that patients in Group 3 (highest LDH levels) had the highest 90-day mortality rate, while those in Group 1 (lowest LDH levels) had the lowest (p < 0.0001). Multivariate Cox regression analysis revealed that every 100 U/L increase in LDH was associated with a higher risk of mortality (HR 1.07, 95% CI 1.01-1.13, p = 0.02). Patients in Group 3 showed a significantly increased risk of mortality (HR 2.29, 95% CI 1.06-4.96, p = 0.036). The subgroup analyses demonstrated stable results across different clinical subgroups. Elevated serum LDH levels, particularly in Group 3, are independently associated with increased 90-day mortality in CTD patients receiving glucocorticoids and hospitalized with pneumonia. LDH may serve as an important prognostic marker for these patients.