Impact of Body Mass Index on Pediatric Complicated Appendicitis and Postoperative Complications
Nutan B. Hebballi1, Stacia DeSantis4, Eric Brown2, Christine Markham3, KuoJen Tsao*1
1Pediatric Surgery, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX; 2Epidemiology, Human Genetics & Environmental Sciences, University of Texas Health Science Center Houston School of Public Health, Houston, TX; 3Health Promotion & Behavioral Sciences, University of Texas Health Science Center Houston School of Public Health, Houston, TX; 4Biostatistics, University of Texas Health Science Center Houston School of Public Health, Houston, TX
Objective: While overweight and obesity have been well studied for complicated appendicitis and its postoperative complications, the effects of being underweight are unknown. Thus, we aimed to assess the impact of the body mass index (BMI) spectrum on complicated appendicitis and its postoperative complications in pediatric patients.
Methods: Using ACS-NSQIP 2016-2020 data, a retrospective review was conducted in pediatric patients (age ≥ 2 to <18 years). Age and gender-specific BMI percentiles were calculated and were further divided into four categories: underweight, normal weight, overweight, and obesity. The 30-day postoperative complications were divided into minor, major, and any complications. Univariate and multivariable logistic regression models were performed controlling for patient demographics, American Society of Anesthesiologists Physical Status Classification and surgery type (open vs laparoscopic). P<0.05 is considered significant.
Results: A total of 23,153 patients were included in the analysis. The odds of complicated appendicitis were 66% greater in underweight patients (odds ratio (OR)=1.66; 95% confidence interval (CI): 1.06-2.59; p-value=0.0263) and 28% lower in overweight patients (OR=0.72; 95% CI: 0.54-0.95; p-value=0.0217) than in patients of normal weight (Table 1). The odds of complicated appendicitis increased by 2% due to a statistically significant interaction between preoperative white blood cells (WBC) and obesity (OR=1.02; 95% CI: 1.00-1.03; p-value=0.0401) (Table 1). Compared to normal weight patients, obese patients had 52% greater odds of mild complications (OR=1.52; 95% CI: 1.18-1.96; p-value=0.0014) (Table 1). In comparison to patients of normal weight, underweight patients had three times the odds of both major (OR=2.77; 95% CI: 1.22-6.27; p-value=0.0146) and any complications (OR=2.82; 95% CI: 1.31-6.10; p-value=0.0083) (Table 1).
Conclusion: Underweight, overweight, and the interaction between overweight and preoperative WBC were associated with complicated appendicitis in pediatric patients. Minor complications were associated with obesity, but major and any complications were associated with being underweight and the interaction between underweight and preoperative WBC. As a result, underweight should also be taken into account as a risk factor for complicated appendicitis and postoperative complications, in addition to overweight and obesity.
Table1. Multivariable logistic regression model for complicated appendicitis and postoperative complications
| Complicated Appendicitis: Adjust OR (95%CI) | Minor Complications: Adjust OR (95%CI) | Major Complications: Adjust OR (95%CI) | Any Complications: Adjust OR (95%CI) | |
| Body Mass Index categories | ||||
| Underweight | 1.66 (1.06, 2.59)* | 1.1 (0.64,1.89) | 2.77 (1.22,6.27)* | 2.82 (1.31, 6.10)† |
| Normal weight | 1.00 | 1.00 | 1.00 | 1.00 |
| Overweight | 0.72 (0.54, 0.95)* | 1.01 (0.73,1.41) | 0.73 (0.44,1.23) | 0.79 (0.49,1.29) |
| Obese | 0.89 (0.70, 1.15) | 1.52 (1.18,1.96)† | 1.12 (0.72,1.74) | 1.29 (0.86, 1.94) |
| Interactions | ||||
| Underweight*Preoperative WBC | 0.98 (0.95, 1.00) | - | 0.94 (0.89,0.99)* | 0.94 (0.89,0.98)† |
| Overweight*Preoperative WBC | 1.02 (1.00,1.03)* | - | 1.02 (0.99,1.05) | 1.01 (0.99,1.04) |
| Obese*Preoperative WBC | 1.01 (0.99, 1.02) | - | 0.99 (0.98,1.02) | 0.99 (0.97,1.02) |
*P < .05 ; †P < .0001
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