Estimated glomerular filtration rate is a marker of mortality in the European Scleroderma Trials and Research Group (EUSTAR) database

Abstract

Objectives: The study aim was to evaluate the estimated glomerular filtration rate (eGFR), its association with clinical disease and its predictive ability with respect to mortality in SSc patients from the European Scleroderma Trials and Research Group (EUSTAR) database. Methods: SSc patients from the EUSTAR database who had items required for the calculation of eGFR at a baseline visit and a second follow-up visit available were included. A cut-off eGFR value of 60 ml/min was chosen for all SSc patients, and 30 ml/min for those with scleroderma renal crisis (SRC). Cox regression and competing risk analysis were performed to evaluate the use of eGFR as a predictive factor of mortality. Results: A total of 3650 SSc patients were included in this study. The median serum level of creatinine and the mean of eGFR were 0.8 mg/dl (interquartile range = 0.6-0.9) and 86.6 ± 23.7 ml/min, respectively. The eGFR was significantly lower in patients with pulmonary hypertension. Overall survival (OS) was significantly reduced in SSc patients with eGFR < 60 ml/min compared with patients with eGFR ≥ 60 ml/min [OS at 5 years 0.763 (95% CI: 0.700, 0.814) vs 0.903 (95% CI: 0.883, 0.919; P < 0.001)]. In multivariable analysis, OS was associated with male gender (P < 0.01), systolic pulmonary arterial pressure (sPAP) (P < 0.001) and eGFR (P < 0.001). The cumulative incidence of deaths due to SSc was associated with increased sPAP (P < 0.001) and reduced eGFR (P < 0.05). The OS at 5 years of 53 SRC patients was not significantly different between SSc patients with eGFR > 30 ml/min and those with eGFR <30 ml/min. Conclusion: eGFR represents a predictive risk factor for overall survival in SSc. The eGFR, however, does not represent a risk factor for death in SRC.