The aim of this study was to evaluate the prognostic performance of two novel laboratory-based biomarker ratios—the red cell distribution width-to-eGFR ratio (RGR) and the NT-proBNP-to-albumin ratio (NTAR)—for predicting LOS, ELOS, in-hospital mortality, and 3-month all-cause mortality in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension. The gene discussed is ALB; the disease is pulmonary arterial hypertension.