Clinical factors and relative risk stratification for repeat platelet transfusion in thrombocytopenia

Objective To identify clinical factors associated with repeat platelet (PLT) transfusion among thrombocytopenic patients and develop an exploratory relative-risk stratification framework for repeat transfusion during hospitalization.Methods This retrospective case-control study included thrombocytopenic inpatients who received at least one PLT transfusion. Patients with repeat transfusion (≥2 transfusions during the same hospitalization, n=145) were compared with those receiving a single transfusion (n = 145). Multivariable logistic regression using clinically prespecified predictors was performed, with ten-fold cross-validated LASSO used to assess variable stability. Model performance was evaluated by AUC, calibration measures, Brier score, and 1,000-resample bootstrap optimism correction. A simplified integer-based score was developed.Results Multivariable analysis identified hematologic malignancy, active bleeding, splenomegaly, lower PLT and hemoglobin levels, absence of thrombopoietic-agent use before the first transfusion, and transfusion timing as factors associated with repeat PLT transfusion. The primary model demonstrated an apparent AUC of 0.805 (95% CI, 0.756–0.855), with a bootstrap-corrected C-index of 0.777. The corrected Brier score was 0.196, and the bootstrap-corrected calibration intercept and slope were 0.001 and 0.860, respectively. The simplified score (0–12 points) stratified patients into low-, medium-, and high-score groups, with observed repeat transfusion proportions of 20.0%, 50.7%, and 83.8%, respectively (trend χ2 = 59.904, P < 0.001).Conclusion Several clinical factors were associated with repeat PLT transfusion. The proposed score may support exploratory relative-risk stratification within the development sample; external validation is required before estimating absolute risk or clinical implementation.