Tight glycemic control linked to no benefit for children in cardiac ICUs

Tight glycemic control after cardiac surgery in children appears to have no significant effect on infection rate, mortality, length of hospital stay or measures of organ failure as compared with standard care, according to results of a new study.

The prospective, randomized SPECS trial included 980 children who were undergoing cardiopulmonary bypass. The children, who ranged in age from newborn to 3 years, were randomly assigned to tight glycemic control (target of 80 mg/dL to 110 mg/dL; n=490) or standard care (n=490). Insulin was administered to 444 of children assigned tight glycemic control compared with just nine children assigned standard care.

“The cardiac problems faced by the children in our patient population are fundamentally different than the cardiac problems affecting adults,” Michael S.D. Agus, MD, of Boston Children’s Hospital and Harvard Medical School, said in a press release. “We chose to focus on [cardiac] ICU patients because the cardiac arena is where the bulk of the benefits have been observed in adults.”

Lack of benefit in children

According to the study abstract, normoglycemia was achieved after a mean 6 hours with tight glycemic control vs. 16 hours with standard care (P<.001). Further, normoglycemia was achieved for a greater proportion of the critical illness period with tight glycemic control (50% vs. 33%; P<.001).

However, tight glycemic control did not significantly decrease the rate of health care-associated infections such as surgical site infections and pneumonia — the primary endpoint of the trial. The rate of infection was 8.6 per 1,000 patient-days in the tight glycemic control group vs. 9.9 per 1,000 patient-days in the standard care group (P=.67).

Using insulin to maintain normal glucose levels also had no demonstrable effect on other secondary outcomes, including length of stay in the cardiac ICU, organ failure and mortality. Tight glycemic control did not benefit high-risk subgroups. Only 3% of patients assigned tight glycemic control had severe hypoglycemia (glucose <40 mg/dL), according to the abstract.

Despite the lack of impact on these outcomes, Agus said there are two successes of this trial.

“One was that we were able to show that children and adults are different when it comes to the benefit of glucose control in a [cardiac] ICU,” he said in the release. “We were also able to demonstrate that we can safely control glucose in a young, vulnerable, sick population.”

Further examination of potential benefits

Next, this research team plans to conduct a randomized, multicenter study of glycemic control. The Heart and Lung Failure — Pediatric Insulin Titration (HALF-PINT) trial will compare two glucose control ranges in hyperglycemic, critically ill children aged 2 weeks to 18 years who are hospitalized in the pediatric ICU with heart and/or lung failure.

Brian P. Kavanagh, MB, FRCPC, commented on the SPECS data in an accompanying editorial: “It seems that — as in adults — claims for survival benefit in critically ill children are incorrect. Furthermore, there is no reason why the effects of glucose control in children would be opposite to those in adults. In aggregate, the data do not support a basis for embarking on a pediatric megatrial.

“Is the door closed on studying glucose homeostasis in the critically ill? No, but it should be closed on the routine normalization of plasma glucose in critically ill adults and children,” Kavanagh said.

For more information:

Agus MSD. N Engl J Med. 2012;doi:10.1056/NEJMoa1206044.

Kavanagh BP. N Engl J Med. 2012;doi:10.1056/NEJMe1209429.

Disclosure: The SPECS study was funded by the NHLBI and others. Agus reports receiving grant money to his institution from the NIH/NHLBI/NCRR/GCRC. Kavanagh reports no relevant financial disclosures.