R1. 이성곤 /pf. 정경환 n engl j med 371;12 nejm.org september 18, 2014

Abstract **Pain from nephrolithiasis : common reason for ER visits  Abdominal CT: m/c high sensitivity for Dx.  However, 1) Exposure to ionizing radiation (long-term ca. risk↑) 2) Annual care costs↑ : about $2 billion in the US. ; CT use(despite its higher sensitivity) : a/w improved pt. outcomes.? Multicenter, randomized trial comparing US with CT.

Method(1) 1) Study design and randomization 15 geographically diverse academic ER, 4 of which were safety-net hospitals Patients(suspected nephrolithiasis): 1:1:1 ratio ① US performed by an emergency physician (point-of-care US) ② US performed by a radiologist ③ Abdominal CT. 2) Study population * ~2013.2: 18~76 yrs of age (flank or abdominal pain)  ER physician imaging order or 1° Dx. Of kidney stone *High risk or obese pts. excluded (acute cholecystitis, appendicitis, aortic aneurysm, bowel d/o, pregnant women or ♂>129kg, ♀>113kg) * Single kidney, RT, dialysis: ineligible SiteLocation Beth Israel Deaconess Medical CenterBoston, MA Grady Memorial Hospital*Atlanta, GA Hennepin County Medical Center*Minneapolis, MN Hospital of the University of PennsylvaniaPhiladelphia, PA Jacobi Medical Center*Bronx, NY John H. Stroger Jr. Hospital of Cook County*Chicago, IL Massachusetts General HospitalBoston, MA Memorial Hermann-Texas Medical CenterHouston, TX Oregon Health & Science University HospitalPortland, OR Rhode Island HospitalProvidence, RI University of California Davis Medical CenterDavis, CA University of California San Francisco-Fresno Community Regional HospitalFresno, CA University of California San Francisco Medical CenterSan Francisco, CA University of Utah Health Care-Hospital and ClinicsSalt Lake City, UT Washington University-Barnes-Jewish HospitalSt. Louis, MO

Method(2) 1) Outcomes *Primary outcomes: ① High-risk Dx. (with complications-missed or delayed Dx.: eg. AAA with rupture, pn. c sepsis, appendicitis c rupture, diverticulitis c abscess or sepsis, bowel ischemia, or perforation, renal infarction, renal stone c abscess, pyelonephritis c uro-sepsis or bacteremia, ovarian torsion c necrosis, or aortic dissection c ischemia) ② Cumulative radiation exposure : Sum of the effective doses from all imagin  6mo. After randomization ③ Total costs: National Medicare reimbursements for cost a/w ER visits

Method(3) *Secondary outcomes : Pts. Were contacted 3, 7, 30, 90, and 180 days  Utilization of health care service, radiation exposure, and Dx. confirmed by means of a review of the medical records (performed by research coordinators) ① Serious adverse events: untoward medical occurrences : death, were life-threatening, required hospitalization, caused persistent or clinically significant disability, or required medical, surgical, or other intervention to prevent permanent impairment ② Related serious adverse events : Acute cholecystitis, appendicitis, and bowel obstruction ③ Emergency department length of stay ④ Return ER visits and hospitalization after D/C ⑤ Hospital admission after emergency department discharge ⑥ Self-reported pain(visual-analogue scale), ⑦ Diagnostic accuracy

Method(4) *Statistical analysis : intention-to-treat principle(except alternative method) : Baseline characteristics & outcomes  Chi-square tests : High-risk Dx. with Cx. & related serious adverse events)  Fisher’s exact test, : Pain score, radiation exposure, & ER length of stay).  Kruskal–Wallis test Distributions for radiatioin exposure: right-skewed~ Sensitivity and specificity : Standards definitions Stratification according to status with respect to a history of nephrolithiasis.

Results(1)

Result(2)

Result(3) 41.6% 63.6% 52.5%

Result(4) Only a single imaging exam.?, :Median length of stay in the ER was significantly shorter in the point-of-care US group than in the other 2 groups : 5.1 hrs (IQR, 3.7 ~ 7.4) /6.4 hrs (IQR 4.9 ~ 8.5) /6.2 hrs (IQR, 4.6 ~ 8.7) (P<0.001). Only a single imaging exam.?, :Median length of stay in the ER was significantly shorter in the point-of-care US group than in the other 2 groups : 5.1 hrs (IQR, 3.7 ~ 7.4) /6.4 hrs (IQR 4.9 ~ 8.5) /6.2 hrs (IQR, 4.6 ~ 8.7) (P<0.001). ED discharge diagnosis Final diagnosisDiagnostic delay (days) Point-of-care US Nephrolithiasis Diverticulitis Nephrolithiasis, UTI Nephrolithiasis Non-specific pain Small bowel obx. Bowel ischemia & resection Pyelonephritis, urosepsis, bacteremia Diverticulitis with abscess Pyelonephritis, urosepsis, bacteremia Urosepsis, bacteremia Pyelonephritis, urosepsis, bacteremia Radiology US Ruptured ovarian cyst Pyelonephritis Nephrolithiasis Ovarian torsion Renal abscess Pyelonephritis, urosepsis, bacteremia Computed tomography Nephrolithiasis, UTI Nephrolithiasis Pyelonephritis, urosepsis, bacteremia Urosepsis, bacteremia 4 17

Result(5)

Diagnostic Accuracy for Nephrolithiasis 1) Proportion of pts with a confirmed stone Dx. within 6 mo. : Similar in the 3 study groups (34.5%/31.2%/32.7%; P = 0.39). 2) Pts. in the US groups : more likely additional diagnostic testing  40.7%/27.0%/5.1% (P<0.001). :*Despite the additional imaging tests  mean total costs : slightly lower US group (a difference of $25 btw. CT & Radiology US, P< ) *1 st imaging test pts. underwent showed that US : lower sensitivity & higher specificity than CT ① Sensitivity : 54% (95% [CI], 48 ~ 60) / 57% (95% CI, 51 ~ 64) / 88% (95% CI, 84 to 92) (P<0.001) ② Specificity :71% (95% CI, 67 ~ 75)/73% (95% CI, 69 ~ 77)/58% (95% CI, 55 ~ 62), (P<0.001). There was no significant difference in results btw those with and those without complete follow-up.

Results Stratified According to History of Nephrolithiasis 1) Primary outcomes : ① High-risk diagnoses c Cx.: no significant differences ② Radiation exposure: significantly lower in the US groups 2) Secondary outcomes: Pts in the US groups- less likely additional Dx. testing with CT ;when they reported a Hx. of nephrolithiasis (31% vs. 36%, P<0.001).

Conclusion **Initial US : was a/w lower cumulative radiation exposure than initial CT, : w/o significant differences in high-risk diagnoses with complications, serious adverse events, pain scores, return emergency department visits, or hospitalizations. **Initial US : was a/w lower cumulative radiation exposure than initial CT, : w/o significant differences in high-risk diagnoses with complications, serious adverse events, pain scores, return emergency department visits, or hospitalizations.