Risk Factors for Cytomegalovirus Reactivation and Its Impact on Clinical Outcomes in Immunocompetent Seropositive Patients Admitted to the Intensive Care Unit: A Single-Center Prospective Observational Study.

Objective: Monitoring cytomegalovirus (CMV) plasma DNAemia is not used in routine clinical practice for immunocompetent patients. However, immunocompetent patients in the intensive care unit (ICU) may develop transient immunosuppression due to severe illness and its treatment, potentially leading to CMV reactivation. This study aimed to investigate the incidence, risk factors, and clinical outcomes of CMV reactivation in non-immunocompromised patients in the intensive care unit (ICU). Materials and Methods: Patients admitted to the Internal Medicine and Anesthesia ICUs were included. CMV-seropositive patients who met inclusion criteria were monitored daily. Quantitative real-time polymerase chain reaction (qPCR) was performed on days 0, 3, 7, 14, 21, and 28 to determine CMV plasma DNAemia. Patients' data was recorded and analyzed by dividing them into reactivation and non-reactivation groups. Results: CMV reactivation occurred in 26 of 146 patients (17.8%), with a mean onset of 10 ± 4.72 days after ICU admission (range: 3-21 days). The reactivation rates in different ICU populations were found to be 31.5% in patients with septic shock, 25% in those with COVID-19, 23.8% in those with sepsis, 18.4% in mechanically ventilated patients, and 11.4% following trauma or surgery. In multivariate analysis, sepsis at ICU admission (odds ratio [OR] 2.88, 95% confidence interval [CI]: 1.017-8.157), Acute Physiology and Chronic Health Evaluation II (APACHE II) score at ICU admission (OR 1.062, 95% CI: 1.003-1.126), and duration of illness before admission (OR 1.048, 95% CI: 1.001-1.097) were independently associated with CMV reactivation. The incidence of fungemia after ICU admission was significantly higher in the group with CMV reactivation. Mortality rates, ICU duration, and hospital stay were comparable between the two groups. Conclusion: Consistent with previous studies, our findings suggested that the presence of infection, especially sepsis, during ICU admission is the most significant risk factor for CMV reactivation. The identification of sepsis and high APACHE II score as independent risk factors supported the association between severe sepsis-related illness and CMV reactivation. In patients with risk factors, CMV reactivation may serve as a marker of disease severity and the level of immunosuppression.