Use of and Regional Variation in Initial CT Imaging for Kidney Stones

Abstract

OBJECTIVE: We sought to determine the prevalence of initial computed tomography (CT) utilization and to identify regions in the United States where CT is highly used as the first imaging study for children with nephrolithiasis. METHODS: We performed a cross-sectional study in 9228 commercially insured children aged 1 to 17 years with nephrolithiasis who underwent diagnostic imaging in the United States between 2003 and 2011. Data were obtained from MarketScan, a commercial insurance claims database of 17 827 229 children in all 50 states. We determined the prevalence of initial CT use, defined as CT alone or CT performed before ultrasound in the emergency department, inpatient unit, or outpatient clinic, and identified regions of high CT utilization by using logistic regression. RESULTS: Sixty-three percent of children underwent initial CT study and 24% had ultrasound performed first. By state, the proportion of children who underwent initial CT ranged from 41% to 79%. Regional variations persisted after adjusting for age, gender, year of presentation, and insurance type. Relative to children living in West South Central states, the highest odds of initial CT utilization were observed for children living in the East South Central US Census division (odds ratio: 1.27; 95% confidence interval: 1.06–1.54). The lowest odds of initial CT were observed for children in the New England states (odds ratio: 0.48; 95% confidence interval: 0.38–0.62). CONCLUSIONS: Use of CT as the initial imaging study for children with nephrolithiasis is highly prevalent and shows extensive regional variability in the United States. Current imaging practices deviate substantially from recently published guidelines that recommend ultrasound as the initial imaging study.

Annual Incidence of Nephrolithiasis among Children and Adults in South Carolina from 1997 to 2012

“…Consequently, there is unwanted variability in evaluation and treatment practices for children with nephrolithiasis, including poor adherence to guidelines aimed at reducing radiation exposure among children with suspected nephrolithiasis and use of surgical interventions that are dependent more on local availability and ease of use than clinical indications (20)(21)(22). The rising incidence of nephrolithiasis among younger girls also has important public health implications.…”

The New Epidemiology of Nephrolithiasis

“…62,63 However, use of CT as the first imaging study for children with nephrolithiasis is common and demonstrates substantial regional variability across the United States. 64 Finally, because nephrolithiasis is associated with an increased risk of ESRD, 47 coronary heart disease, 65 and bony fracture, 66 it is possible, although unproved, that patients who develop kidney stone disease during childhood will be at higher risk for these adverse health conditions given the long lifetime over which they can develop. Table 1 is a list of dietary risk factors for kidney stones examined in epidemiological studies.…”

Is the Economic Impact and Utilization of Imaging Studies for Pediatric Urolithiasis Across the United States Increasing?

“…This finding is in keeping with previous studies demonstrating similar increases in CT scan use in children over similar time periods. 15, 16 While CT is more sensitive for the detection of stones, the benefits must be carefully weighed against the risks in children. There is a relatively small estimated risk of malignancy in children undergoing imaging; that increased risk is directly correlated with increased ionizing radiation dose.…”