N-terminal pro Brain Natriuretic Peptide as predictor of outcome in scleroderma renal crisis.

OBJECTIVES: Although in scleroderma renal crisis (SRC) outcome has improved to a great extent with the introduction of ACE inhibitors, there remains significant mortality and morbidity with frequent requirement for renal replacement therapy. Therefore, novel biomarkers to identify patients at high risk of poor outcome would be valuable. The aim of this study was to assess the role of the N terminal fragment of pro Brain Natriuretic Peptide (N-TproBNP) as predictor of outcome in SRC.

METHODS: 20 subjects with confirmed SRC were retrospectively enrolled. Clinical data, full blood count, creatinine, eGFR and N-TproBNP at presentation were collected.

RESULTS: Patients requiring renal replacement therapy presented significantly higher levels of N-TproBNP and creatinine (p>0.01), lower eGFR (p<0.01) and haemoglobin levels (p=0.01) and shorter disease duration (p<0.01) compared to those who did not require dialysis. Whereas all the candidate variables significantly predicted renal outcome in univariate models, N-TproBNP was the only variable to hold significance in predicting renal outcome in a Firth's multivariate logistic regression model (p=0.05, OR 7.6). ROC curve of N-TproBNP to identify patients requiring renal replacement therapy provided a sensitivity of 88.9%, with a specificity of 81.8% at a cut-off value of 360 pmol/L (95% CI 0.84-1.00, area under the curve 0.94). In our cohort, this provided a positive predictive value of 80% and a negative predictive value of 90%.

CONCLUSIONS: N-TproBNP peptide may be a useful biomarker in risk-stratification of renal outcome in SRC, selectively identifying patients likely to require renal replacement therapy.