Abstract Rationale Leukopenia is common after lung transplantation, often resulting from immunosuppressive and prophylactic medications used to prevent graft rejection and infection. Higher mortality, increased cancer risk, and susceptibility to opportunistic infection are well-documented leukopenia complications, yet patient-specific risk factors remain poorly understood. This study aims to identify risk factors for leukopenia and create a predictive model for its development post-transplant. Methods We conducted a retrospective review of 78 lung transplant recipients at Keck Medical Center for incidence of leukopenia from April 2014-July 2023. Leukopenia was defined as a white blood cell (WBC) count 4,000/µL within two years post-transplant. Data collected included demographics, pre-transplant variables (labs, diagnoses, comorbidities), and post-transplant variables (immunosuppression, antiviral prophylaxis, leukocyte counts, opportunistic infections). Univariate analyses identified potential predictors, which were then entered into a multivariable logistic regression to construct the predictive model. Model performance was assessed by area under the ROC curve (AUC). Results Within two years, 70% (55/78) of patients developed leukopenia, with 58% occurring within 6 months post-transplant. No significant demographic differences were observed. Factors associated with leukopenia in univariate analysis included pre-transplant BMI, pre-transplant WBC, pulmonary hypertension (pHTN), interstitial lung disease (ILD), and post-transplant prednisone 0.01) and ILD (OR = 0.25, 95% CI 0.06-1.09, p = 0.06) were also associated with decreased risk of leukopenia. Conversely, post-transplant prednisone (OR = 5.86, 95% CI 1.51-22.72, p = 0.01) and valganciclovir (OR = 4.31, 95% CI 0.82-22.67, p = 0.09) showed strong positive associations, though valganciclovir did not reach statistical significance. The model demonstrated good discrimination (AUC = 0.82) and calibration (Hosmer-Lemeshow = 0.12). Conclusions Lower pre-transplant BMI and WBC appear to predispose patients to leukopenia, possibly secondary to reduced bone marrow function and decreased hematopoietic reserves. Additionally, the associations with prednisone and valganciclovir suggest that enhanced monitoring or weight-based dosing could mitigate risk. Further investigation is needed to explain the unexpected protective effects of pHTN and ILD. Next steps include expanding sample size and employing time-to-event analysis to refine risk prediction and model utility. This abstract is funded by: None
Ann et al. (Fri,) studied this question.