Once thought to be on the wane, investigators who examined millions of death records found that mortality rates for idiopathic pulmonary fibrosis have increased in recent years and show signs of continuing on an upward path, reports the American Journal of Respiratory and Critical Care Medicine.

Between 1992 and 2003, the age-adjusted mortality rate from idiopathic pulmonary fibrosis rose by 28% in men, and 41% in women. This upward trend has surpassed mortality rates for such lethal diseases as acute myeloid leukemia and bladder cancer.

Pulmonary fibrosis causes inflammation and scarring deep within the lung tissue. Survival rates after diagnosis are generally three to five years. No effective treatment exists and its causes remain unknown although smoking is a suspected factor.

Some researchers imply that it only appears that there are greater instances of the disease because the technology for detecting it has improved greatly in recent years. "In the 1990s the technology improved and high resolution CT scans may have led to more clinical recognition of the disease," said lead investigator Amy Olson, MD, MSPH, a research fellow at the University of Colorado Health Sciences Center in Boulder.

There is the possibility that the prevalence of the disease is actually increasing, acknowledged senior investigator Kevin Brown, MD, vice chair of medicine at National Jewish Medical and Research Center in Denver. "But we can’t sort out those two possibilities [better detection or higher prevalence] based on the data we have."

Historic smoking patterns may also be a cause, said Olson, with higher rates of smoking in the past leading to an increase of pulmonary fibrosis today. Olson and her colleagues examined the cause of death listed for more than 28 million people in the U.S. and determined that more than 175,000 had died from pulmonary fibrosis.

Pulmonary fibrosis is now common enough that it has to be considered when making a primary diagnosis in people with respiratory problems. "I think primary care physicians need to start learning about this disease because it is being recognized much more frequently, and clearly the mortality rate is going up," said David Ingbar, MD, president of the American Thoracic Society and director of the pulmonary, allergy and critical care division at the University of Minnesota.

Efforts are being made to find effective treatments for the disease, said Dr. Brown. The National Institutes of Health is funding 12 medical centers across the nation to study idiopathic pulmonary fibrosis. The National Jewish Medical Center is among the funded centers. Duke University in Durham, N.C., is coordinating the project. The centers are charged with developing and conducting clinical trials to identify better therapies.