Background: The correlation between platelet count and bleeding has been well described, although no formal methods for applying this information to clinical decisions are available. The authors developed a clinical prediction rule to guide the prophylactic use of platelet transfusions among patients with lymphoma or solid tumors.
Methods: The Bleeding Risk Index (BRI) was developed from logistic regression analysis of a randomly selected 750-chemotherapy cycle derivation set using data from Day 1 of cycles. The sensitivity and specificity of a BRI-based prophylaxis strategy were compared in a 512-cycle validation set with two strategies based on initiation of prophylaxis when platelet counts fell below thresholds of 20,000 per microL or 10,000 per microL.
Results: Factors that were predictive of bleeding included any prior episode of bleeding (odds ratio [OR], 5.6; 95% confidence interval [95% CI], 2.2-14.0), treatment with a drug affecting platelet function (OR, 5.1; 95% CI, 2.0-12.6), bone marrow metastases (OR, 4.3; 95% CI, 1.7-10.8), a baseline platelet count < 75,000 per microL (OR, 3.5; 95% CI, 1.4-8.9), genitourinary or gynecologic malignancy (OR, 3.3; 95% CI, 1.3-8.2), a Zubrod performance status score > 2 (OR, 3.4; 95% CI, 1.4-8.5), and treatment with agents that were highly toxic to the bone marrow (OR, 2.2; 95% CI, 1.0-5.4). Compared with 20,000 and 10,000 platelet threshold strategies, the BRI-based strategy provided the best trade-off between sensitivity for major bleeding episodes (80%) and specificity for any bleeding (84%).
Conclusions: Patients with lymphoma or solid tumors who are at high risk of bleeding can be identified reliably on Day 1 of a chemotherapy cycle. An individualized, BRI-based approach to bleeding prophylaxis provides a highly sensitive and specific alternative to traditional, nonindividualized platelet threshold strategies.
Copyright 2002 American Cancer Society.