RT Journal Article SR Electronic T1 High level of lactate dehydrogenase and ischaemia–reperfusion injury regulate the multiple organ dysfunction in patients with COVID-19 JF Postgraduate Medical Journal JO Postgrad Med J FD The Fellowship of Postgraduate Medicine SP postgradmedj-2022-141573 DO 10.1136/postgradmedj-2022-141573 A1 Aleena Ashraf A1 Afrose Liaquat A1 Sana Shabbir A1 Saleem Ahmed Bokhari A1 Zainab Tariq A1 Zainab Furrukh A1 Afraz Ahmad Raja A1 Muhammad Jawad Khan YR 2022 UL http://pmj.bmj.com/content/early/2022/03/22/postgradmedj-2022-141573.abstract AB Background Multiple organ damage has been observed in patients with COVID-19, but the exact pathway is not known. Vital organs of the human body may get affected after replication of SARS-CoV-2, including the lungs, heart, kidneys, liver and brain. It triggers severe inflammation and impairs the function of two or more organ systems. Ischaemia–reperfusion (IR) injury is a phenomenon that can have disastrous effects on the human body.Methods In this study, we analysed the laboratory data of 7052 hospitalised patients with COVID-19 including lactate dehydrogenase (LDH). A total of 66.4% patients were men and 33.6% were women, which indicated gender difference as a prominent factor to be considered.Results Our data showed high levels of inflammation and elevated markers of tissue injury from multiple organs C reactive protein, white blood cell count, alanine transaminase, aspartate aminotransferase and LDH. The number of red blood cells, haemoglobin concentration and haematocrit were lower than normal which indicated a reduction in oxygen supply and anaemia.Conclusion On the basis of these results, we proposed a model linking IR injury to multiple organ damage by SARS-CoV-2. COVID-19 may cause a reduction in oxygen towards an organ, which leads to IR injury.Data are available upon reasonable request.