Incidence of and Factors Associated with Acute Kidney Injury After Scoliosis Surgery in Pediatric Patients

Purpose: We sought to identify the national incidence of acute kidney injury (AKI) associated with pediatric posterior spinal fusion (PSF) surgery for scoliosis, and to determine factors that increase risk.

Methods: The 1998-2014 National Inpatient Sample (NIS), a large United States hospital discharge database, was queried for discharges aged 0-17 years with International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for scoliosis undergoing PSF for the outcome of AKI. Discharges were divided into those with AKI and unaffected. We fit adjusted logistic regression models to yield point estimates, odds ratios, 95% confidence intervals, and p values for the weighted, national population sample with postulated risk factors. The fit of the multivariable regression model was tested using the Hosmer-Lemeshow test, and collinearity using the variance inflation factor.

Results: The NIS contained 103,270 weighted discharges meeting inclusion criteria. AKI incidence was 0.1%. Multivariable logistic regression model showed significantly increased odds ratios with thrombocytopenia, rhabdomyolysis, chronic kidney disease, abnormal coagulation, and male sex. AKI increased both hospital stay and cost by threefold compared to unaffected children.

Conclusion: This study suggests that AKI after pediatric PSF is rare. It is associated with abnormal coagulation, chronic kidney disease, and rhabdomyolysis, but not with the number of vertebral levels fused. Female sex appears to be protective. The retrospective nature of study and reliance on ICD-9-CM codes may under-represent the incidence of AKI in pediatric PSF patients.