‘Differences across countries’
Adrienne Randolph, MD, a pediatrician at Harvard Medical School, Boston, and senior author of a large case series of patients with MIS-C, said that the Canadian study is valuable because it includes children from three countries. “It’s very interesting that there are differences across countries,” she said. “The patients in Iran had the highest percentage (58.7%) going into the ICU, whereas Costa Rica had the lowest percentage (9.2%), and the percentage going to the ICU in Canada (34.7%) was less than the percentages we see in the U.S. – which is pretty consistently about 60% to 70% of MIS-C patients going into the ICU.” Dr. Randolph was not involved in the current study.
Reasons for differences in the rates of ICU visits will be important to explore in the effort to standardize diagnostic criteria, stratification of severity, and recommendations for treatment of MIS-C, said Dr. Randolph.
“What is consistent is that the younger kids, zero to 5 years, in general are less ill,” she said. “That’s been consistent across multiple countries.” It’s unclear whether the cause of this difference is that parents observe younger patients more closely than they do teenagers, or whether other aspects of adolescence, such as prevalence of obesity and attendant inflammation, are at work, said Dr. Randolph.
What is also unclear is why hospitalized patients with MIS-C had higher percentages of ICU admission in the latter part of the study period, compared with the earlier period. “Did the patients change, or did practice change as we got to understand the disease process?” asked Dr. Randolph. “It could be that they got better at the diagnosis and were weeding out some of the patients who they realized didn’t need to be hospitalized. At the very beginning, we had a very low threshold to admit patients, because we didn’t know, and then, over time, people understood what was going on and felt more comfortable monitoring them as outpatients.”
This study was partially funded by a Janeway Foundation Research Grant to support data collection. Dr. Robinson disclosed no conflicts of interest. Dr. Randolph reported receiving royalties from UpToDate and personal fees from the La Jolla Pharmaceutical Company.
A version of this article first appeared on Medscape.com.