Pediatric obesity and adverse outcomes following deformity correction surgery for adolescent idiopathic scoliosis: A cross-sectional analysis using 2015-2019 NIS data.

Background: Obesity in the pediatric population has been a growing medical concern over the last few decades with a prevalence of 19.7% as of 2017-2020. Obesity is a risk factor for greater scoliotic curves and failure of conservative therapy for adolescent idiopathic scoliosis (AIS). Establishing a correlation between obesity and a wide variety of adverse outcomes following scoliosis surgery can assist in the preoperative consultation with the family and proper optimization of the patient for scoliosis fusion surgery.

Methods: The National Inpatient Sample (NIS) was used to access inpatient data from 2015 to 2019. Pediatric patients with idiopathic scoliosis admitted for spinal deformity correction via posterior spinal fusion of over 8 levels were identified. Patients were stratified based on the comorbid diagnosis of obesity. Variables that were significantly associated with outcomes (p < 0.05) were used in a multivariable logistic regression to control for confounders. Backwards stepwise p-value removal was used to build the final model and model fit was assessed using the area under the curve.

Results: A total of 855 obese and 17,285 non-obese pediatric patients undergoing posterior instrumented fusion for scoliotic deformity correction were identified. The obese group was associated with a higher rate of SSI (0.6% vs 0.1%, p < 0.001), UTI (1.2% vs. 0.3%, p < 0.001), and AKI (0.6% vs 0.1%, p = 0.12) compared to the normal BMI group. Obese patients were also more likely to have a non-routine discharge when compared to non-obese (4.7% vs. 2.3%, p < 0.001). The rate of having more than one complication occurring postoperatively was higher in the obese group, however, this finding was not significant (0.6%, vs 0.4%, p = 0.385). On multivariate regression analysis, obesity was positively associated with SSI (OR = 2.758, CI = 0.999-7.614, p = 0.050), UTI (OR = 2.221, CI = 1.082-4.560, p = 0.030), non-routine discharge (OR = 1.515, CI = 1.070-2.147, p = 0.019), and an extended LOS (OR = 1.869, CI = 1.607-2.174, p < 0.001).

Conclusion: Obesity was associated with postoperative blood transfusion, SSI, UTI, increased length of stay, and non-routine discharge after pediatric AIS deformity surgery. In addition to the increased morbidity seen in obese patients, we also identified the significantly increased cost of care for this group when compared to non-obese patients. These data should be used for a robust preoperative risk assessment and evidence for BMI optimization prior to deformity correction for AIS.