Diagnostic value of lactate dehydrogenase in COVID-19: A systematic review and meta-analysis

BACKGROUND: This meta-analysis outlines the role of elevated lactate dehydrogenase (LDH) levels in assessing the severity of coronavirus disease 2019 (COVID-19). METHODS: The current study was designed as a systematic review and meta-analysis. Embase, Pub-Med, Web of Science, Scopus and Cochrane Central Register of Controlled Trials were searched to identify the usefulness of LDH as a marker of COVID-19 severity. All extracted data were analyzed using RevMan V.5.4 or STATA V.14 software. RESULTS: A total of 264 records were selected for this meta-analysis. Pooled analysis showed that LDH levels were statistically significantly lower in the group of survivors compared to patients who died in hospital (standardized mean differences [SMD] = −3.10; 95% confidence interval [CI]: −3.40 to −2.79; I(2) = 99%; p < 0.001). Lower LDH levels were observed in non-severe groups compared to severe course of COVID-19 (SMD = −2.38; 95% CI: −2.61 to −2.14; I(2) = 99%; p < 0.001). The level of LDH was statistically significantly lower in the severe group compared to the critical group (SMD = −1.48; 95% CI: −2.04 to −0.92; I(2) = 98%; p < 0.001). Patients who did not require treatment in the intensive care unit (ICU) showed significantly lower levels of LDH compared to patients who required treatment in the ICU (SMD = −3.78; 95% CI: −4.48 to −3.08; I(2) = 100%; p < 0.001). CONCLUSIONS: This meta-analysis showed that elevated LDH was associated with a poor outcome in COVID-19.