MONDAY, March 29, 2004 (HealthDayNews) -- Children with sickle cell disease, an inherited disorder marked by distorted red blood cells, are living longer than ever before, Texas physicians report.
"We're turning what once was a fatal disease of childhood into a chronic disease of adulthood," says Dr. George R. Buchanan, director of the Southwestern Comprehensive Sickle Cell Center in Dallas and lead author of a report on survival in the June issue of Blood.
Although the research is based on a long-term study of just 711 children with sickle cell disease treated at the Texas center, "we believe that the results are typical, especially for people treated at a comprehensive sickle cell care center," says study co-author Dr. Charles T. Quinn, an assistant professor of pediatrics at the University of Texas Southwestern Medical Center.
A decade ago, only half the children with sickle cell disease were expected to survive childhood, Quinn says. The new study says that 85.6 percent of patients at the Dallas center with sickle cell anemia, the most severe and most common form of the condition, were alive at age 18.
The 18-year-old survival rate for children with milder forms of the disease was 97.4 percent, the report says.
Sickle cell disease occurs in people who inherit two mutated genes for hemoglobin, the molecule that carries oxygen in red blood cells. The mutation is common among people of African descent and those from other tropical areas because a single mutated gene does no harm and confers some protection against malaria.
It's estimated that 11 percent of black Americans carry a sickle cell gene, and that 60,000 to 70,000 have the disease.
This is probably the first study to report the dramatic increase in survival for sickle cell patients, Quinn says; studies cited in the new report are more than a decade old.
While a number of factors have contributed to the improvement, one of the most important is newborn screening, which now is done in virtually every state, Buchanan says. Patients are now being identified at birth, so they can get the treatment they need, he says.
"These babies used to die of infections at 3 or 4 months of age, and parents never even knew they had the disease," he says.
Major advances in treatment are aimed at the infectious diseases to which sickle cell patients are particularly vulnerable, Buchanan says. They now are given frequent doses of penicillin and also are given a vaccine that protects against seven forms of Pneumococcus.
"In the absence of these interventions, 20 percent of children used to die by age 5," Buchanan says.
Longer survival is creating a new challenge for patients and their doctors, Quinn says. The Texas group is continuing to follow patients in their adult years to assess their medical problems and quality of life.
"Not only will they need close monitoring, but they continue to need to have comprehensive care," Quinn says.
It is known that long-term sickle cell survivors can have problems with their lungs, brain and kidneys, Buchanan says.
"The challenge for us is to identify differences from one patient to another and predict which will have which kind of organ failure," he says. "If we get information early enough, we might develop more effective ways to prevent organ failure."