Although cystic fibrosis patients in clinical trials had more severe illness, worse lung function, a lower weight level and more respiratory infection than non-participants, their involvement in research studies resulted in less lung function decline over a 7-year period.
The research results appeared in the first issue for January 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Christopher H. Goss, M.D., M.Sc., of the Departments of Medicine and Pediatrics at the University of Washington Medical Center in Seattle, along with three associates, looked at data from 13,041 patients in the Cystic Fibrosis Foundation Registry between 1992 and 1998.
Despite their worse clinical status at the beginning of the study, participants' lung function declined at 1.33 percent per year, as compared with 1.52 percent for non-participants.
Of the 8,375 patients followed for the entire 7-year study period, 2,635 individuals (30.2 percent) were enrolled in at least 1 of 32 Institutional Review Board clinical trials.
"Subjects who were involved in clinical trials were more likely to be older, have commercial health insurance, be white, be colonized with a bacterial infection like Pseudomonas aeruginosa, have worse lung function and have more office visits," said Dr. Goss.
Cystic fibrosis (CF), one of the most common inherited life-shortening illnesses, is characterized by the production of thick, sticky mucus that eventually blocks the small airways, leading to inflammation and infection. Mucus also affects the pancreatic ducts, preventing normal digestion and weight gain. Respiratory failure is the primary cause of early death. CF incidence runs from 1 in 2,000 to 1 in 3,200 live births.
According to the authors, access to better health care through more office visits appeared to be the reason explaining less lung function decline for clinical trial participants.
"Given that there may be potential benefits to study participation, CF clinicians need to ensure adequate opportunities for participation in studies for all eligible subjects," said Dr. Goss.
He added that the persons most likely to participate in the study were those without a high school education who worked full-time.
According to the authors, this CF study was the first to compare clinical trial participants against a majority in a disease category within a specific country.