Incidence and clinical outcome of cytomegalovirus infection in recipients of allogenic haematopoietic stem cell transplantation; experience from a tertiary care hospital in Pakistan

Background: Infectious complications are a major factor affecting the prognosis of HSCT recipients. Cytomegalovirus is responsible for substantial mortality in post-transplant patients. The objective of our study was to assess the frequency and outcomes of CMV infection in patients undergoing hematopoietic stem cell transplant. Material and Methods: This retrospective study was conducted at the Aga Khan University Karachi, from January 2015 to December 2021. Quantitative PCR was done to detect CMV infection. Survival analysis was performed using the Kaplan-Meier method. Cox regression was employed to assess factors affecting survival. Results: We included 112 patients. The frequency of CMV infection in the transplant period was 52%, with 97% of cases occurring within the first 100 days. CMV infection within 30 days occurred in 57%, between 30 and 100 days in 38% and after 100 days in 5% of patients. CMV PCR positive patients had a mean survival of 43 months (95% CI: 31.3-55.2), while CMV PCR negative patients showed an estimated mean survival of 70 months. Cox regression showed CMV positive adults with GVHD had a lower mean survival. CMV status (HR: 2.2, p-value: 0.04) and ATG use (HR: 2.3, p-value: 0.04) were associated with an increased hazard of death. No other variables were significant. Conclusion: Overall frequency of CMV infection in our study was 52% with the majority occurring within 100 days of transplant. Adults with GVHD and patients receiving ATG had a decreased mean survival time. Understanding of factors worsening the prognosis of CMV infection is important to improve clinical practice. Keywords: Cytomegalovirus, Allogenic stem cell transplantation, ATG, GVHD