Evaluation of principal component–based and synthetic feature representations in machine learning prediction of hospital length of stay in COVID-19 patients using XGBoost algorithm. MedInnovations Journal, [S. l.], v. 2, n. 2, p. 1–18, 2026. DOI: 10.69139/j5e22841. Disponível em: https://medinnovations.eu/index.php/medi/article/view/14.. Acesso em: 8 sep. 2026.