Risk factors for severe neutropenia in patients with cytomegalovirus infection treated with ganciclovir: A retrospective observational study.

Objective: This study aimed to investigate the baseline neutrophil count as a risk factor for ganciclovir-induced neutropenia in greater detail.

Materials and methods: This retrospective observational study included patients who received ganciclovir at Kindai University Nara Hospital between April 2006 and June 2023. Exclusion criteria were as follows: patients under 18 years of age, those who received chemotherapy within 2 weeks prior to ganciclovir administration, those who underwent blood transfusions or received granulocyte colony-stimulating factor injections during the observation period, those treated for fewer than 2 days, patients with a baseline neutrophil count < 1,000 cells/mm³, and patients with missing data on any study variables. The primary endpoint was the occurrence of severe neutropenia, which was analyzed using Cox regression analysis and the Cochran-Armitage trend test.

Results: To the 345 patients who met the inclusion criteria, exclusion criteria were applied, and 158 were ultimately identified as eligible patients. Patients with baseline neutrophil counts < 1,500 cells/mm³ were at significantly higher risk of severe neutropenia compared to those with baseline counts ≥ 4,000 cells/mm³ (HR = 16.86, 95% CI = 1.64 - 173.50, p = 0.018). Additionally, the incidence of severe neutropenia tended to increase significantly as the baseline neutrophil count decreased (p < 0.001).

Conclusion: These findings underscore the importance of monitoring baseline neutrophil counts before initiating ganciclovir treatment, particularly in patients with conditions associated with low neutrophil levels, such as hematological disorders.