The addition of inflammatory ( pro-adrenomedullin ) and cardiac ( pro-atrial natriuretic peptide ) blood biomarkers measured upon hospital admission further improved the prognostic capabilities of the PSI ( AUC increase from 0.79 to 0.83 ; P < 0.0001 ) and the CURB-65 score ( AUC increase from 0.73 to 0.80 ; P < 0.001 ) .