Researchers revisit pulmonary arterial hypertension survival
Jan 6, 2010 - 4:59:12 AM
Setting out to determine the survival of patients with pulmonary arterial hypertension (PAH), researchers at the University of Chicago Medical Center and their colleagues also discovered that an equation used for more than 20 years to predict survival is outdated. Accordingly, they developed and recently published a new survival prediction equation that will impact clinical practice and the drug development process.
In PAH, the pulmonary arteries, which carry blood from the heart to the lungs to pick up oxygen, become restricted, forcing the lower right chamber of the heart to pump harder. This leads to shortness of breath, limited exercise capacity, fatigue, heart failure and death. Often the condition goes undetected until it is advanced. Untreated, patients with PAH have a very poor prognosis.
That prognosis is determined using an equation developed by a landmark National Institutes of Health study published in 1987, well before there were any Food and Drug Administration approved therapies for PAH. The first such therapy was approved in 1995; today there are seven.
Since 1987, great progress has been made in understanding and treating PAH, so a few years ago we decided that it was time to study contemporary survival, said Mardi Gomberg-Maitland, MD, MSc, Associate Professor of Medicine and Director of Pulmonary Hypertension at the University of Chicago Medical Center. Our results show that survival is vastly improved today. That led us to rework the NIH equation, which has been a standard measuring stick for more than 22 years.
Gomberg and her colleagues at the Medical Center and Northwestern University's Feinberg School of Medicine studied the survival of 576 PAH patients in their registry. Of these patients, 282 had idiopathic, familial, and anorexigen-associated PAH, which matches the conditions of the 187 patients in the pioneering NIH study.
Using the NIH equation, these 282 patients would have been expected to have one-, three- and five-year survival rates of 65%, 43% and 32%, respectively. In fact, their survival rates were much higher: 92%, 75% and 66%, respectively.
This new formula is important for patients who want to know what, on average, to expect from their disease and for doctors who want to give accurate advice, said Stephen L. Archer, MD, Harold Hines Jr. Professor and Chief of Cardiology at the University of Chicago Medical Center and co-author of the study. We hope others will test our work. If it is validated by others it could be a very useful tool.
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