Abbokinase Equivalent to Surgery in Kids' Empyema but Is Less Expensive

LONDON, July 14 -- An increasingly popular surgical treatment for childhood empyema is 25% more expensive - but no more effective - than intrapleural fibrinolytic treatment with Abbokinase (urokinase), according to researchers here.

Abbokinase, instilled through a chest drain, "should be the primary treatment of choice" rather than video-assisted thoracoscopic surgery (VATS), according to Samatha Sonnappa, M.D., D.Ch., of the Portex Respiratory Unit at the Institute of Child Health here.

Interest in VATS in children with empyema has been increasing, and several reports have shown it is safe and effective, Dr. Sonnappa and colleagues reported in the second July issue of the American Journal of Respiratory and Critical Care Medicine.

The only randomized study to compare VATS with fibrinolytics was in adults, the researchers said; it showed VATS had a higher success rate, fewer days in hospital, and fewer days with a chest drain. The results can't be extended directly to children, the researchers said, because mortality in adults is about 20%, while it is rare in children.

Nevertheless, Dr. Sonnappa and colleagues hypothesized that VATS would outperform intrapleural Abbokinase in children. To test the notion, they prospectively enrolled 60 children, all younger than 16, who were referred to the Great Ormond Street Hospital for Children here for management of parapneumonic effusions.

The children were randomized to treatment with intrapleural Abbokinase or VATS. The primary outcome measure was length of hospital stay after the intervention; secondary outcomes included the number of chest drain days, the failure rate, the radiologic outcome at six months, and total treatment costs.

The study found no significant differences in most of the outcome measures. Specifically:

• The median length of hospital stay after the intervention was six days in both groups.
• The failure rate was 16.6% in both groups.
• Chest drains were removed a day earlier in the VATS group, but the difference was not clinically significant because it did not affect the length of hospital stay.
• Although some children were lost to follow-up at six months, there were no significant difference on chest x-rays of the remaining patients in each group.

The only major difference - it reached statistical significance at P<0.001 - was in treatment costs, the researchers found.

Both the average and the median costs were higher for VATS than for Abbokinase -- ,379 and ,146 versus ,127 and ,914. "Therefore, VATS on average is ,250 more expensive for each patient than is intrapleural Abbokinase," the researchers said. The figure is based on British charges, converted to U.S. dollars.

The cost analysis is limited, the researchers noted. It did not include start-up costs, did not consider effectiveness, was based on two groups of only 30 patients, and reflects prices at a single institution in the England.

However, based on those costs and the anticipated prevalence of childhood empyema in the England and the U.S., using intrapleural Abbokinase as the first line of treatment would save .5 million and million a year, respectively, for the health services of the two countries, the researchers calculated.

The study is "clearly a helpful step in the direction of providing needed insight into the management of pleural infection in children," said Julian Allen, M.D., of the Children's Hospital of Philadelphia and Peter Mattei, M.D., of the University of Pennsylvania School of Medicine.

However, they said in an accompanying editorial, the conclusion of the study that Abbokinase should be first-line treatment depends on the apparent "clinical equipoise" demonstrated between the two treatments. "One concern about this study is that while (the groups) are closely matched, there may have been small differences," they wrote, including slightly worse disease in the surgical study group.

Secondly, they noted, measures such as length of stay after intervention, total length of stay, and failure rates are "subjectively determined by the attending physician, who is not blinded to the treatment arm" - a factor that could introduce bias.