Background: Oxygenated hemoglobin (OxyHem) in arterial blood may reflect disease severity in patients with systemic sclerosis (SSc), particularly among those with pulmonary manifestations, such as pulmonary hypertension (PH).
Objectives: Hence, the aim of this study was to analyze the predictive value of OxyHem in SSc patients screened for PH.
Methods: Systemic sclerosis patients were screened for PH including right heart catheterization, laboratory and clinical assessment. They were followed for 3.2 ± 2.6 (median 3.0) years. Oxygenated hemoglobin was measured by multiplying the concentration of hemoglobin by oxygen saturation assessed in arterialized capillary blood. Kaplan–Meier analysis was performed using the defined threshold from receiver operating characteristic. Prognostic power was compared with known parameters of prognostic significance in SSc using uni- and multivariable analysis. Clinical parameters of patients with high and low OxyHem were compared by Student’s t-test.
Results: A total of 280 SSc patients were screened, and 267 were included in the analysis (82% female, 59.8 ± 13.4 years, 73.8% limited cutaneous SSc); 56 patients had manifest PH and 112 interstitial lung disease (ILD). Low OxyHem ≤12.5 g/dL at baseline was significantly associated with a worse survival (P = 0.046) among SSc patients. In the multivariable analysis, the presence of ILD, age ≥60 years and diffusion capacity (DLCO) ≤65% were associated with worse survival among SSc patients. The combination of low DLCO and low OxyHem at baseline could predict the development of early pulmonary vascular disease at follow-up (sensitivity 79.6%).
Conclusions: This study detected, for the first time, that an OxyHem level ≤12.5 g/dL is a prognostic predictor in SSc patients. Further studies are needed to confirm these results.
KEY CONTRIBUTORS
Panagiota Xanthouli, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany; Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Germany; Division of Rheumatology, Department of Internal Medicine V: Hematology, Oncology and Rheumatology, University Hospital Heidelberg, Heidelberg, Germany Ojan Gordjani: Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany Christina Alessandra Eichstaedt, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany; Laboratory for Molecular Genetic Diagnostics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany Nicola Benjamin, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany Franziska Trudzinski, Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Germany Benjamin Egenlauf, Satenik Harutyunova, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany; Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Germany Alberto M. Marra, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany; Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Germany; Department of Translational Medical Sciences, “Federico II” University and School of Medicine, Naples, Italy Nicklas Milde, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany Christian Nagel, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany; Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Germany Norbert Blank, Hanns-Martin Lorenz, Division of Rheumatology, Department of Internal Medicine V: Hematology, Oncology and Rheumatology, University Hospital Heidelberg, Heidelberg, Germany Ekkehard Grünig, Centre for Pulmonary Hypertension, Thoraxklinik at Heidelberg University Hospital, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany; Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Germany
