Lucca Tamara Alves Carretta, Leonardo Di Cosmo, Lucas Copolillo Faria, Nicole Baptista de Oliveira, Pedro Rodrigues Teixeira, João Vitor Andrade Fernandes, Lara Bourguignon Lopes, Fernando Rocha Oliveira
Thrombocytopenia is a known and potentially severe manifestation of dengue hemorrhagic fever, raising concerns regarding the risk of hemorrhage. To prevent such complications, prophylactic platelet transfusion (PT) has been suggested as a possible intervention. We aimed to evaluate the efficacy and safety of PT in dengue-associated thrombocytopenia. We conducted a systematic literature search for randomized controlled trials and cohorts across PubMed, Cochrane Library, Web of Science, Scopus, and Embase from inception to November 2025. Primary outcomes were time to platelet count ≥ 50 × 10³ platelets/µL and mortality. Secondary outcomes were bleeding events and length of hospital stay. Risk of bias was assessed using the RoB 2 and ROBINS-I tools. Of 1,900 articles screened, 9 studies were included (6 retrospective cohorts, 2 RCTs, and 1 prospective cohort), comprising 3,377 patients. The PT group included 2,383 patients, whereas the standard supportive care group included 994 patients. PT was not associated with significant reductions in time to platelet recovery (mean difference, 0.73 days; 95% CI: -0.01 to 1.47; I² = 95.9%) or length of hospital stay (mean difference, 0.53 days; 95% CI: -0.15 to 1.22; I² = 96.7%) but was associated with significantly higher risks of mortality (risk ratio, 3.61; 95% CI: 1.12-11.66) and bleeding events (risk ratio, 1. 37; 95% CI: 1.03-1.82). Prophylactic platelet transfusion demonstrated no measurable benefit and was associated with increased mortality and bleeding risk, arguing against its routine use in dengue-associated thrombocytopenia. Evidence was primarily derived from retrospective studies, limiting interpretability and warranting randomized studies.