Author: Michael Vlessides
Overall obesity rates among pediatric surgical patients have changed little over the past nine years, despite a nationwide trend in increasing obesity among the population at large.
“The prevalence of obesity among children has been steadily rising across the country, but it hasn’t really been documented whether or not we’re seeing a similar trend among the operative population,” said Aleda Thompson, MS, a senior statistician at the University of Michigan, in Ann Arbor.
“The purpose of our study was to look at that population through a multi-institutional lens using the MPOG database to see if there’s a similar trend among the operative population, because, obviously, obesity comes with its own set of potential complications, especially when you’re factoring in an operation,” Thompson said.
She and her colleagues looked at data from all patients aged 2 to 17 years, for whom a complete set of body mass index (BMI) data were available. Children were excluded from the analysis if they were undergoing cardiac, bariatric, obstetric or unknown surgical procedures. “We excluded these procedures because they are very specialized populations and we wanted to get more of an overall feel of what was happening,” Thompson said in an interview with Anesthesiology News. Additional procedures on the same child within a calendar year also resulted in exclusion from the study. Case year was categorized into two-year increments, as has been done in similar research.
For purposes of this study, children’s weights were classified using percentiles from growth charts published by the CDC. Obesity was classified as follows:
- class 1: BMI percentile between 95% and 120% of the 95th CDC percentile;
- class II: BMI between 35 and 40 kg/m2 or BMI percentile between 120% and 140% of the 95th CDC percentile; and
- class III: BMI at least 40 kg/m2 or BMI percentile of 140% or more of the 95th CDC percentile.
“The CDC has standard growth curves for kids, but they’re not really effective for predicting outcomes above the 95th percentile,” Thompson explained. “So, it’s become standard that you use a percentage of the CDC’s published 95th percentile.”
The researchers predefined a significant change in overall obesity rate (classes I, II and III) to be at least 5%, whereas for severe obesity (classes II and III) it had to be at least 1%.
As Thompson reported at the 2019 annual meeting of the International Anesthesia Research Society (abstract F121), 294,321 cases from 32 MPOG institutions were eligible for study inclusion. Interestingly, obese patients were a median of two years older for both male and female individuals, compared with normal-weight children. Not surprisingly, obese patients were also significantly less likely to have an ASA class of I (males, 28% vs. 40%; females, 24% vs. 39%; P<0.001 for both).
Of note, the analysis revealed that rates of overall obesity (i.e., all classes) were virtually unchanged between 2008-2009 and 2016-2017, for both the entire study cohort and when stratified by sex. Similar patterns were observed for severe obesity.
“Because of our a priori definition, we did not observe a significant increase in obesity rates over the course of the analysis,” Thompson said. “The P value would have been statistically significant, but that’s likely because our sample size was so big.”
Although the study provides encouraging news regarding childhood obesity in the United States, the status quo is not without its challenges. “Given the number of obese children that present for surgery, the entire perioperative period, including the preoperative clinic, can offer very good points for learning opportunities where parents and children can learn about obesity in general and how to prevent it,” she explained. “It may well be that it’s the first time a child has seen a doctor in a long time, and perhaps anesthesiologists or other practitioners can broach the topics of diet and exercise.”
Claude Abdallah, MD, MSc, was intrigued by the study’s results. “It would be exciting to see these results presented with consideration to changes, if any, within different geographic areas/states,” said Dr. Abdallah, an associate professor of anesthesiology and pediatrics at George Washington University Medical Center, in Washington, D.C .
“This study shows that obese patients were significantly less likely to have an ASA class of I, and [it] would be interesting to differentiate if a higher ASA classification attribution was secondary to obesity or to documented associated or unrelated pathologies,” Dr. Abdallah added.