Serum Lactate Dehydrogenase Elevates and Inversely Correlates with Platelet Count in Immune Thrombocytopenia: A Case-control Study in Adults

Abstract

Background: Platelets have high lactate dehydrogenase (LDH) activity. Although widely used as a marker of hemolysis, the rise of LDH in high platelet turnover without concomitant hemolysis -such as in immune thrombocytopenia (ITP)- is not well established. This study aimed to evaluate pre and post-treatment serum LDH levels in patients diagnosed with ITP and compare this with a healthy control group (CG). Materials and Methods: Two hundred twenty-six patients who were newly diagnosed with ITP [123 patients with treatment indication (ITP-T) and 103 patients without treatment indication (ITP-WT)] and 131 patients as CG were enrolled. Serum LDH level were measured at diagnosis and during early response evaluation. Pre-and post-treatment LDH levels of ITP-T patients were compared and the differences in LDH according to the response in the first two weeks were examined. Results: LDH was higher in newly diagnosed ITP patients than in the CG (218 IU/L, and 159 IU/L, respectively p<0.001). LDH levels of ITP-T, ITP-WT, and CG were 241.8 IU/L, 191.5 IU/L, and 159.3 IU/L, respectively (p<0.001). An inverse correlation was found between LDH levels and platelet counts in the entirety of the newly diagnosed ITP patient group (p<0.001). However, when the subgroups of ITP patients were examined, a correlation was found only in the ITP-T group (p=0.009); no correlation was found in the ITP-WT group. The alteration of the LDH in the ITP-T group according to the response was -6.7 IU/L, -15.3 IU/L, and -21.6 IU/L in patients without response, response, and complete response, respectively (p>0.05). Conclusion: The LDH level was found to be moderately high in patients with ITP at the time of diagnosis, and slightly improved after the treatment. Oncoming LDH isoenzyme studies may be determined to find out which isoenzyme is responsible for its rise and if can it be used as a marker in the diagnosis or follow-up of ITP.