Comparison Omicron in renal transplant recipients and general population: a case-control study

Abstract Background Omicron was introduced as one of the variants of concern covid-19. Due to their immunosuppressed condition, renal transplant recipients (RTRs) are a vulnerable group. Thus, the present study was conducted to compare RTRs and non-RTRs infected with Omicron, with a special focus on clinical symptoms, imaging characteristics, disease severity, and outcomes. Methods The case group included 62 RTRs infected with the Omicron strain and the control group included 60 patients non-RTRs infected with the Omicron strain were hospitalized from December 22, 2021, to March 20, 2022 at the peak of Omicron in Tehran, Shiraz and Babol, Iran. RTRs with Omicron were compared to healthy controls in terms of their clinical symptoms, laboratory results, patterns of lung involvement on high resolution computed tomography (HRCT) and unfavorable outcomes, including rates of ICU hospitalization, mechanical ventilation (MV) use, and mortality. Results Among the clinical symptoms, significantly more people in the case group experienced diarrhea (P = 0.045). The most common symptoms were the same in both groups, but the order in the case group was fever (58%), chills (54.8%), dry cough (46.7%), and dyspnea (43.5%) and in the control group was dry cough (58.3%), fever (45%), chills (40%), and dyspnea (40%). Overall, the prevalence of pulmonary involvement was greater in the control group. It was shown that RTRs had a reduced absolute lymphocyte count (ALC) and platelet count. As a result, RTRs' creatinine levels rose more than those of non-RTRs. There was a statistically significant difference between the RTRs and control groups in terms of ICU admission, mechanical ventilation (MV), length of hospital stay, and mortality as unfavorable outcomes. Conclusion In conclusion, clinical symptoms were not significantly different except diarrhea. The severity based on CDC criteria and risk of adverse outcomes, such as MV, ICU admission, and mortality, were significantly different between RTRs under prolonged immunosuppression and the control group.