Background: The COVID-19 pandemic has had an enormous impact on hemodialysis patients. This study investigated changes in hemodialysis treatment at our hospital after the start of the pandemic.Methods: We analyzed data from the Diagnosis Procedure Combination (DPC) system. Data for inpatients receiving dialysis during collection periods A (before the COVID-19 pandemic) and B (after the start of the COVID-19 pandemic) were extracted and compared. The numbers of inpatients and new patients, the number of patients admitted (by department), duration of stay, mortality, place of residence, surgical procedures, and DPC classification were compared.Results: There were no significant differences between periods in patient age, duration of hospital stay, number of new patients, number of ambulance transports, number of deaths, body mass index, comorbidities, laboratory variables before the first dialysis after hospitalization, or patient area of residence. Although differences were observed among the departments, the numbers of emergency dialysis inpatients and maintenance dialysis inpatients increased. The number of surgeries also increased overall, particularly for maintenance dialysis patients (P = 0.0273). The percentage of DPC III patients was significantly higher in period B (P=0.0368).Conclusions: The number of surgeries performed on maintenance dialysis patients and the overall DPC III rate significantly increased after the start of the COVID-19 pandemic at our hospital, suggesting that COVID-19 worsened the condition of maintenance dialysis patients and prolonged hospital stays.