Abstract: Ｏｂｊｅｃｔｉｖｅ：Shanghai has experienced two waves of the COVID-19 epidemic in 2022. The aim of our study was to understand the difference of the laboratory results in maintenance hemodialysis patients at different stages of the epidemic.
Ｍｅｔｈｏｄｏｌｏｇｙ：The laboratory tests of maintenance hemodialysis (MHD) patients from January 2022 to January 2023 at the Blood Purification Center of Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine were retrospectively analyzed, and the complications of chronic kidney disease in each stage were compared: before the first round of the epidemic (January 2022), after the first round of the epidemic (July 2022), before the second round of the epidemic(October 2022), and after the second round of the epidemic (January 2023).
Ｒｅｓｕｌｔｓ：259 MHD patients were enrolled in this study. During the first round of the epidemic, the infection rate of patients in our center was 6.7％, and a total of 5 patients died, all of which were unrelated to COVID-19 infection. During the second round of the epidemic, the infection rate was 78.5％, and a total of 15 patients died, of which 9 were related to COVID-19 infection. The overall hemoglobin compliance rates of patients in the four stages were 45.1％, 39.0％, 52.0％ and 36.2％. And the highest compliance rate was in stage 3(October 2022), which was statistically different from other stages (P<0.05). The rates of iron metabolism compliance were 19.4％, 15.3％, 18.3％ and 24.4％, respectively. The albumin compliance rates were 66.4％, 61.9％, 77.0％ and 56.9％, respectively, and there were significant differences between the stage 3 and other stages (P<0.05). The calcium compliance rates were 69.2％, 70.7％, 70.7％ and 54.9％, respectively, and there were significant differences between the stage 4 and other stages (P<0.05). The phosphorus compliance rates were 34.0％, 32.5％, 38.2％ and 32.9％, respectively, and there were no significant differences between the stages. The compliance rates of iPTH during the stage 3 and the stage 4 were 28.4％ and 23.3％ (P=0.232), respectively. There were no significant differences in Scr, BUN, or potassium levels between different stages.
Ｃｏｎｃｌｕｓｉｏｎ：Different epidemic prevention and control measures and different COVID-19 variant bring different infection rates and disease severity, but the decrease of CKD complication rate will certainly happen. During the epidemic, special attention should be paid to the correction of anaemia and nutritional status of patients. Patients in the intermission period of the epidemic had the highest compliance rate.

Key words: COVID-19 epidemic, maintenance hemodialysis, complication