Mortality rates for pediatric rheumatology patients are significantly lower than previously reported, according to the largest study done yet on the topic in the United States.
In the February 2010 issue of Arthritis and Rheumatology, a Cleveland Clinic research team reports that the overall mortality rate in the U.S. for all pediatric patients with rheumatic diseases wasn’t worse or greater than the general population, even in conditions associated with increased mortality.
“Our reaction was obviously satisfaction that we hopefully are improving the outcome of our patients with better therapy. But we still have a way to go in some diseases,” says Philip Hashkes, MD. He was the lead researcher while serving as the section head of Pediatric Rheumatology at the Cleveland Clinic and now heads the Pediatric Rheumatology Unit at Shaare Zedek Medical Center in Jerusalem, Israel.
An estimated 300,000 children in the U.S. have some form of arthritis or rheumatic disease, according to The Childhood Arthritis and Rheumatology Research Alliance (CARRA). These diseases result in health risks and limit function and quality of life.
In some previous studies, conditions including juvenile rheumatoid (JRA) arthritis, childhood systemic lupus erythematosus (SLE), dermatomyositis, various vasculitides, and systemic sclerosis have also been associated with an increase in mortality.
But Cleveland Clinic researchers say these previous studies were small, relied on doctor surveys that were not verified, followed patients for less than 10 years and reported only on specific diseases, centers or regions.
For their new study, which was funded by the Northeast Ohio Chapter of the Arthritis Foundation, Cleveland Clinic researchers mined data from the Pediatric Rheumatology Disease Registry. It is the world’s largest rheumatology registry, with information collected from 62 centers on nearly 50,000 patients diagnosed between 1992 and 2001. The scientists then confirmed deaths through death certificates, medical records and referring physicians and reviewed charts and death certificates to determine causes of death.
They discovered 110 deaths among 48,885 patients in the registry. This was two to three times lower than what they expected to find. The entire study group’s survival rate was 99.9 percent at five years and 99.7 percent at 10 years. For juvenile rheumatoid arthritis and all connective tissue diseases, it was 99.8 percent at five years and 99.1 percent at 10.
“The mortality rate for all diseases was lower than previous studies, but was increased compared to the U.S. age and sex matched population for systemic lupus erythematosus, connective tissue disease, dermatomyositis and primary vasculitis. That’s as expected since these diseases involve important organs and the treatment is quite aggressive with potential serious adverse effects,” Dr. Hashkes says.
He continues, “We were most surprised by systemic JRA that was not significantly greater than the general population, and the improved prognosis of kids with pain syndromes compared to the general population with most of their deaths occurring from non-natural causes like motor vehicle accidents, suicide and homicide.”
“It is possible that improved treatments and protocols during the 1990s and early 2000s contributed to improved mortality outcomes,” Dr. Hashkes says. But he adds, “There still is excess mortality in some of the conditions and we have still have a lot of work to continue and decrease mortality.”
Dr. Hashkes says he hopes his study results will be encouraging to patients and families with the diseases and he hopes it gives doctors more accurate information to pass on about the prognosis of these diseases in children. He also hopes there will be more research using the registry.
“I think this cohort should be followed for mortality trends in the next decade, to monitor especially for the long-term effects of our medications, excess malignancies for example, and to search for cardiovascular deaths similar to that found in adult diseases like rheumatoid arthritis and SLE.”
“I think it’s very interesting to see these things. I wouldn’t say there’s very much that’s surprising about it and in a way that’s reassuring in the sense that the patients who seem to have the most deaths were the patients with the diseases that we know are some of the most difficult to treat,” says Barbara Adams, MD, the Director of Pediatric Rheumatology at the University of Michigan School of Medicine in Ann Arbor. “The general trends are what I expected, but I’m not sure if these numbers really say how many people are really alive because we weren’t able to garner all of it. “
Dr. Adams says this study only involves children who were seeing pediatric rheumatologists. “That’s how the data got into the database. So in a way we’re not looking at the overall survival rate. Just at those people who are already linked up with a pediatric rheumatologist,” she explains. “We know there are people who are left out. I have an outreach clinic in northern Michigan in Traverse City and the people who come there, the kids who have real disease, many of their families have had no idea there’s a specialist in this kind of area.”