The impact of obesity on pediatric inpatients with urinary tract infections in the United States.
INTRODUCTION
Urinary tract infections (UTI) are common infectious disorders, and obesity is an increasing public health problem worldwide. Several studies have suggested that childhood obesity may be associated with the development of UTI. However, the potential effects of obesity on the clinical outcomes of UTI in children remain unknown.


MATERIALS AND METHODS
Hospital discharge records for patients aged 18 years or younger with a diagnosis of UTI were extracted from the 2012 Kids' Inpatient Database. We used the International Classification of Diseases, Ninth Revision, Clinical Modification codes, and classified each patient as obese or not. We compared the total hospitalization costs, total length of hospital stay in days, and risks of hypertension, acute kidney injury, and septicemia between obese and non-obese patients, using propensity score matching and stabilized inverse probability weighting methods.


RESULTS
Of 51,918 patients with UTI, 1488 were obese and 50,430 were non-obese. A multivariable logistic regression model calculated propensity scores using baseline characteristics as dependent variables. One-to-one propensity matching created 1488 pairs. In the propensity-matched analyses, a significant difference was observed between the obese and the non-obese for risks of hypertension (8.1% vs. 1.8%; risk ratio 4.44; 95% CI 2.95-6.71). The total mean hospitalization cost in the obese group was 1.29 times higher than that in the non-obese group (95% CI 1.13-1.47). The total mean length of hospital stay in the obese group was 1.29 times longer than that in the non-obese group (95% CI 1.16-1.44). Stabilized inverse probability weighting analyses showed similar results to the propensity matched analyses (Table), except for a significant result for the risk ratio for acute kidney injury (risk ratio 1.64; 95% CI 1.18-2.26.


CONCLUSIONS
These findings indicate that obesity may be an important risk factor for hypertension and acute kidney injury among hospitalized children with UTI. Obesity may also be an economically complicating factor for their hospitalizations, which indicates the importance of the prevention for obesity.