UMBRELLA protocol: systematic reviews of multivariable biomarker prognostic models developed to predict clinical outcomes in patients with heart failure 由 Maria D. L. A. Vazquez-Montes, Thomas P. A. Debray, Kathryn S. Taylor, Benjamin Speich, Nicholas Jones, Gary S. Collins, F. D. R. Richard Hobbs, Emmanuella Magriplis, Hugo Maruri-Aguilar, Karel G. M. Moons, John Parissis, Rafael Perera, Nia Roberts, Clare J. Taylor, Nikolaos P. E. Kadoglou, Marialena Trivella, on behalf of the proBHF group