Can REVEAL Tool Predict Survival in SSc-Related Pulmonary Arterial Hypertension?

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A prognostic tool developed to predict survival in patients with various forms of pulmonary arterial hypertension (PAH) is fairly accurate in predicting survival outcomes for many patients with PAH related to systemic sclerosis (SSc-PAH), according to a new study. However, the prognostic accuracy is less reliable for SSc-PAH patients with the highest risk of death.

That’s the conclusion of a recently published study that examined the accuracy of a prognostic equation and risk score calculator derived from the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) to predict survival outcomes in a specific group of patients with PAH.¹ Developed from prospectively gathered data from a large cohort of patients with PAH, the REVEAL calculator is used to predict one-year survival in patients with various forms of PAH.² The prognostic equation and risk score comprise 19 parameters identified through multivariate analysis as clinical and hemo­dynamic variables independently associated with survival. The prognostic equation provides an estimated prediction of one-year survival, whereas the risk score provides an integer value corresponding to predicted probability of one-year survival.

In the study, investigators examined the accuracy of the REVEAL calculator when applied specifically to patients with PAH related to SSc. According to the study’s senior author, Stephen C. Mathai, MD, MHS, associate professor of medicine in the Division of Pulmonary and Critical Care Medicine at Johns Hopkins University School of Medicine, Baltimore, specific tools to predict survival in SSc-PAH patients are lacking despite good therapies for PAH that may improve patient outcomes.

“This is the first study to examine the accuracy of survival prediction equations in SSc-PAH,” he says. “The results suggest predictors of risk may carry different weight in SSc-PAH compared [with] other forms of PAH.”

The Study

Dr. Mathai

In the study, Mathai and colleagues prospectively gathered data on 292 patients with newly diagnosed SSc-PAH taken from the Johns Hopkins Pulmonary Hypertension Program (JHPHP; n=117) and Pulmonary Hypertension Assessment Recognition of Outcome in Scleroderma (PHAROS; n=176) study. Data obtained included vital signs and hemodynamic measurements, lab analyses, pulmonary test results, a six-minute walk test, computed tomography of the chest, echocardiogram reports and clinical assessment of World Health Organization Functional Class.

The investigators tabulated the REVEAL prognostic equation and risk score for each patient in this cohort to test its accuracy to predict one-year survival. One-year survival probability was calculated based on the assessment of 19 parameters for each patient at the time of and prior to the time at risk. The time at risk was defined slightly differently for the patients enrolled through the JHPHP and PHAROS registry, but basically began the date patients were diagnosed with PAH based on right heart catheterization. Death was determined by the Social Security death index and clinical records.

To calculate the REVEAL risk score, the same 19 parameters were used. Based on the predicted probability of one-year survival, patients were stratified into five risk groups: low risk (>95% survival), average risk (90–95% survival), moderately high risk (85–90% survival), high risk (70–85% survival) and very high risk (<70% survival).