Introduction: Renal colic is among the most painful conditions that patients experience. The main outcome determinants for patients with renal colic are stone size, location and hydronephrosis; however, little is known about the association of pain with these parameters. Our objective was to determine whether more severe pain is associated with larger stones, more proximal stones or more severe hydronephrosis, findings that might suggest the need for advanced imaging, hospitalization or early intervention. Methods: We used administrative data and structured chart review to study all adult emergency department (ED) patients in two cities with a renal colic diagnosis over one-year. Patients with missing imaging results or pain scores were excluded. Triage nurses recorded numeric rating scale (NRS) pain scores on arrival. We stratified patients into mild (NRS <4), moderate (NRS 4-7) and severe (NRS 8-10) pain groups, as per CTAS guidelines. Stone size (mm) and location (proximal, middle, distal ureter, or renal) were abstracted from imaging reports, while index admissions were determined from hospital discharge abstracts. We used multivariable linear regression to determine the association of arrival pain with stone characteristics and hydronephrosis severity (primary outcome), and we used multivariable logistic regression to determine the association of pain with index hospitalization (secondary outcome). We also performed a stratified analysis looking at ureteral vs. kidney (intrarenal) stones. Results: We studied 1053 patients, 66% male, with a mean age of 48 years. After controlling for patient and disease characteristics, we found no significant association between pain severity and stone size (b=−0.0004; 95%CI = -0.0015, 0.0008) or stone location (b = 0.0045; 95%CI: -0.020, 0.029). Nor did we find an association between pain and hydronephrosis severity (b = 0.016; 95%CI: -0.053, 0.022, p = 0.418). Stratified analyses using a Bonferroni correction for multiple comparisons revealed the same absence of associations in the kidney and ureteral stone subgroups. Arrival pain did not predict index admission (OR = 0.82, 95% CI: 0.59, 1.16). Conclusion: Arrival pain scores are not associated with stone size, stone location or hydronephrosis severity, and do not predict index visit hospitalization in ED patients with renal colic. Severe pain should motivate efforts to minimize treatment delays, but do not suggest the need to modify advanced imaging or admission decisions.

Introduction: Non-steroidal anti-inflammatory drugs (NSAIDs) are first-line analgesics for emergency department (ED) patients with renal colic. Lower doses of intravenous (IV) ketorolac may provide similar pain relief to standard dosing in patients with acute pain. Patients with renal colic may be at increased risk of acute kidney injury; exposing them to lower doses of NSAIDs may put them at lower risk while providing equally effective analgesia. We conducted a pilot study to determine the feasibility of a randomized trial comparing the effectiveness and safety of low with standard ketorolac dosing in ED patients with suspected renal colic. The primary objective was to demonstrate the ability to achieve an enrolment target of 2 patients per week. Methods: We enrolled a convenience sample of adults presenting to an academic urban ED with unilateral flank pain suspected to be renal colic. We randomized patients to 10 mg (low dose, intervention) or 30 mg (standard dose, control). Participants, treating physicians and nurses, and researchers were blinded to treatment allocation. Our main feasibility outcome was the recruitment rate. Secondary outcomes were changes in pain scores (0-10) at 30 and 120 minutes post-ketorolac administration, vital signs, adverse events and ED length of stay. Results: We approached 82 patients, of whom 47 (57.3%) were eligible. Of these, 36 consented to participating and 30 were randomized. The proportion of screened patients who were enrolled was 36.6% (30/82). We completed enrolment over a 21-week period, with an average recruitment rate of 1.5 patients/week (range 0-4). The average baseline pain score for all participants was 6.9 (SD = 2.1). At 30 minutes post-ketorolac administration, the low dose group had a mean pain reduction of 2.0 points compared to a pain reduction of 1.7 in standard dose group (difference = 0.3, 90% CI: -0.7 to 1.4). Conclusion: These preliminary results support the possibility that low dose ketorolac may be efficacious in this patient population. We did not meet our target recruitment of 2 patients per week as this was primarily due to restricted recruitment hours. To successfully conduct a larger trial, we would need to expand both recruitment hours and the number of sites.

Introduction: Ureteral colic is a common painful disorder. Early surgical intervention is an attractive management option but existing evidence does not clarify which patients benefit. Based on lack of evidence, current national specialty guidelines provide conflicting recommendations regarding who is a candidate for early intervention. We compared treatment failure rates in patients receiving early intervention to those in patients offered spontaneous passage to identify subgroups that benefit from early intervention. Methods: We used administrative data and structured chart review to study consecutive patients attending one of nine hospitals in two provinces with an index emergency department (ED) visit and a confirmed 2.0-9.9 mm ureteral stone. We described patient, stone and treatment variables, and used multivariable regression to identify factors associated with treatment failure, defined as the need for rescue intervention or hospitalization within 60 days. Our secondary outcome was ED revisit rate. Results: Overall, 1168 (37.9%) of 3081 eligible patients underwent early intervention. Patients with small stones <5mm experienced more treatment failures (31.5% v. 9.9%) and more ED revisits (38.5% v. 19.7%) with early intervention than with spontaneous passage. Patients with large stones ≥7.0mm experienced fewer treatment failures (34.7% v. 58.6%) and similar ED revisit rates with early intervention. Patients with intermediate-sized 5.0-6.9mm stones had fewer treatment failures with intervention (37.4% v. 55.5%), but only if stones were in the proximal or middle ureter. Conclusion: This study clarifies stone characteristics that identify patients likely to benefit from early intervention. We recommend low-risk patients with uncomplicated stones <5mm generally undergo initial trial of spontaneous passage, while high-risk patients with proximal or middle stones >5mm, or any stone >7mm, be offered early intervention.

Introduction: The optimal initial management approach for ureteral colic is unclear. Guidelines recommend spontaneous passage for most patients, but early stone intervention may rapidly terminate acute episodes. We compared 60-day treatment failure rates in matched patients undergoing early intervention versus spontaneous passage. Methods: We used administrative data and structured chart review to study all emergency department (ED) patients at nine Canadian hospitals who had an index ureteral colic visit and a computed tomography (CT) confirmed 2.0-9.9 mm stone during 2014. Using Cox Proportional Hazards models, we assessed 60-day treatment failure, defined as hospitalization or rescue intervention, in patients undergoing early intervention compared to propensity-score matched controls undergoing trial of spontaneous passage. Results: From 3,081 eligible patients, mean age 51 years and 70% male, we matched 577 patients in each group (total 1154). Control and intervention cohorts were balanced on all parameters and propensity scores, which reflect the conditional probability a patient would undergo early intervention, were similarly distributed. In the time to event analysis, 21.8% in both groups experienced the composite primary outcome of treatment failure (difference = 0%; 95% CI, -4.8 to 4.8%). Early intervention patients required more ED revisits (36.1% v. 25.5%; difference 10.6%; 95% CI 5.3 to 15.9%) and more 60-day hospitalizations (20.1% v. 12.8%). The strongest predictors of adverse outcome were stone size, proximal or middle stone location, and ED length of stay. Conclusion: If applied broadly to patients with 2.0-9.9mm ureteral stones, an early interventional approach was associated with similar rates of treatment failure, but more hospitalizations and emergency revisits. Research clarifying subgroups most likely to benefit will facilitate better targeting of early intervention, potentially reducing patient morbidity and improving system utilization.

Introduction: The number of CT scans prescribed in the Emergency department (ED) for suspected renal colic has increased over recent years without an associated improvement in patient-centred outcomes. We assessed whether Point-of-Care Ultrasound (PoCUS) decreases the use of formal radiologic imaging. Methods: We completed a retrospective cohort study on consecutive patients 18 years of age and older presenting to the ED with suspected uncomplicated renal colic in a tertiary care centre in Québec in 2016. Exclusion criteria included: previous urologic intervention, solitary kidney, dialysis, fever, pyuria, acute kidney injury, pregnancy, suspicion of a serious alternative diagnosis or persistent symptoms despite analgesia. We compared the proportion (95%CI) of formal radiologic imaging performed (Ultrasound or CT) in patients who had PoCUS in the ED vs. those who did not. Two-tailed Fisher exact test (α = 0.05) and odds ratios (95%CI) calculated from multivariate logistic regression models adjusted for age, gender, Charlson Index and previous renal colic were used to compare the two groups. The reliability of data collection was evaluated with a kappa score (95%CI). Results: 169 patients with uncomplicated renal colic were included. There was no difference between the groups in terms of age, gender, Charlson Index, or previous renal colic. The PoCUS level of training and the doctor's education level was significantly higher in the PoCUS group. There was a non-significant trend towards less formal imaging in patients of the PoCUS group 65/88 (73.9% [63.4-82.7%]) vs. the non-PoCUS group 69/81 (85.2% [75.6-92.1%]), p = 0.087. After adjustment for confounders, the patients not evaluated with PoCUS were more likely to have formal imaging with a significant odds ratio of 2.41 [1.05-5.56]). Among patients who underwent a CT, incidentalomas were found in 16.5% and only 2.0% demonstrated significant findings leading to changes in ED management, such as an alternative diagnosis, need for admission, or an urgent urological intervention. Inter-observer agreement was excellent between assessers with a kappa score of 0.88 [0.66-1.00]. Conclusion: ED patients with uncomplicated renal colic who are investigated with PoCUS tend to have fewer formal imaging test. When CT scans were performed, incidentalomas were found in 16.5% and ED management changed only 2.0% of the time. PoCUS appears to be a useful tool for decreasing CT utilisation in this low-risk ED population.

Background: Acute pain is a common presentation in the Emergency Department (ED) and inadequacy in its treatment can lengthen stay. Earlier analgesia use and discharge has been associated with positive patient experiences and improved pain management. Validated ‘fast-track pathways’ to aid physician decision making in analgesic administration is associated with decreased waiting times in renal colic diagnoses. Aim Statement: Our aim was to create an order set, for an approach to patients with acute pain, to reduce median time from point of triage to analgesia. We sought to reduce median time by 15 minutes, for ED patients with renal colic in the three months after implementation as compared to three months before. Measures & Design: We used a literature review and comparison to existing order sets at other EDs to design our draft. We focused our evaluation on patients with renal colic. We underwent multiple revisions based on stakeholder feedback and educated both physician and nursing teams about the order set. The utilization, however, was at physician discretion. We implemented the order set on March 30, 2017. After three months, an electronic retrospective chart review identified patients with a final renal colic diagnosis. For each patient, we captured triage time using electronic records and time to analgesia with the medication cart. Utilization of order sets was confirmed via manual chart audit. Evaluation/Results: A run chart showed worsening times after the intervention. Median time to analgesia in minutes, 3 months prior (n = 90) and post (n = 93) intervention, increased from 228 to 310 minutes, although the range was very large. Chart audits demonstrated a considerably low uptake of the order set with a small gradual increase from 0% to 20% over the 3-month period. Discussion/Impact: There was insufficient uptake of the Acute Pain order set preventing impact on time to analgesia. Changes in occupancy likely contributed to the worsening times. There was an increase in utilization over the 3-month period and could be due to increased awareness. This demonstrates that interventions require more than implementation to be effective. Difficulties in implementation were due to the document not being readily available. We have organized the nursing staff to attach order sets onto charts based on triage assessment and will re-assess with another PDSA cycle after this intervention.

Introduction: Renal colic is a common presentation which exerts a significant burden on healthcare infrastructure. A significant proportion of patients managed with observation may return to the Emergency Department (ED) prior to spontaneous passage due to inadequate analgesia. It is unclear whether early urologist consultation would limit the burden of renal stones by reducing returns to the ED. We wished to determine whether urologist referral from the ED department is associated with fewer returns to the ED with renal colic. Methods: We conducted a retrospective chart review using RECORD methodology of consecutive patients diagnosed with CT-confirmed, ureteric or renal calculi in our ED over a two-year period. Disposition was categorized as either hospital admission, outpatient urologist referral, follow up with primary care, or no follow up. The primary outcome was the 30-day ED re-presentation for renal colic. Multivariate logistic regression was used to identify predictors for ED-return. Results: In total, 232 patients met our inclusion criteria. Urgent or outpatient urologist referral was not associated with a significantly lower ED return rate when compared to patients with no follow-up. Surprisingly, urologic intervention and stent placement were both independent predictors for ED return (OR: 2.03; 95% CI: (1.06-3.88); p:0.03) and (OR:2.08; 95% CI: (1.07-4.05). Conclusion: A significant proportion of patients who underwent urologist-led intervention returned to the ED with renal colic. Further study may help clarify the role of early urologist referral for renal calculi, as this may not reduce ED return rates when compared to conservative management.

Background: Choosing Wisely (CW) recommends patients under age 50 with uncomplicated, recurrent renal colic do not require CT scans. Despite this, CT use has risen dramatically in the past two decades, resulting in unnecessary radiation, cost and prolonged length of stay (LOS). Additionally, a common alternative – formal ultrasound (US) – is not always available. Returning for US can add 10 hours to LOS. We introduced a clinical management pathway (CMP) for low-risk patients with renal colic utilizing point-of-care ultrasound (POCUS) and evaluated its impact on emergency department (ED) CT rates and LOS. Aim Statement: By April 2019, we aim to reduce CT utilization by 50% and time from physician initial assessment (PIA) to discharge by 1 hour for patients under age 50 presenting to Sunnybrook ED with uncomplicated, recurrent renal colic. Measures & Design: The primary intervention was a CMP developed collaboratively with local urologists. The CMP uses POCUS to assess for hydronephrosis (HN) as a marker of nephrolithiasis. Patients with HN receive follow-up in urology clinic without confirmatory imaging. Patients without HN proceed to usual care. An Ishikawa diagram helped identify barriers to success. Subsequent PDSA cycles included the introduction of reference cards, POCUS workshops and online modules. Outcome measures were ED CT utilization and PIA to discharge times. Process measures were referrals to urology clinic and proportion of patients receiving XR, US and no imaging. Balancing measures were urology CT utilization, alternate diagnoses and return ED visits. Data was plotted on a run chart. Evaluation/Results: Data collection is ongoing and will conclude by April 2019. Interim data shows patients enrolled in the CMP have a reduction in mean PIA-to-discharge time of 173 minutes. Fidelity – specifically, the willingness of ED physicians to use POCUS compared to the ease of ordering CTs – is the biggest challenge to success. Discussion/Impact: This study addresses the feasibility of CW recommendations and utilizes POCUS as a tool for recurrent renal colic. Collaboration with Urology will provide insight into the CMP's sustainability and downstream impact. Reduction of unnecessary CTs will lead to improved patient safety and reduced costs. Decreased PIA-to-discharge times will reduce overcrowding, shorten wait times and improve access to imaging for other patients. Finally, this project may encourage use of POCUS for low-risk patients with renal colic.

Introduction: Our objective is to investigate predictors of adverse patient reported outcomes during the 10 days after an index emergency department (ED) encounter for ureteral colic. Methods: This prospective two-city patient experience survey enrolled ED patients with confirmed 2-10 mm ureteric stones. Researchers telephoned consenting patients 10 days post-ED visit and assessed quality of life (QoL) using survey items from the VR-12 Health Outcome Survey. We used five survey items and three other variables to derive a composite measure of patient adverse experience (AE). The association between patient characteristics, symptoms and perceptions of care with outcome was determined using multiple logistic regression. Results: Of 224 patients studied (68% male, mean age 52 years) 154 (68.8%) indicated that one or more of the following AEs occurred during their 10day followup interval: 103 (46%) reported that the impact of pain on their life was >4/10; 87 (39%) described poor or fair health status; 83 (37%) required >7days for return of normal function; 66 (27.7%) had >2 severe pain episodes per day; 62 (27.7%) required ED revisit or hospitalization; 47 (21%) found usual activities were limited most or all the time; 45 (20%) required >2 opioid doses/day; and 24 (10.7%) lost >7 work days. A composite measure derived from 3 survey items (days to normal, pain impact, health status) captured 92% of patients with adverse experiences. On multivariable logistic regression modeling, the strongest predictors of adverse (composite) outcome were male sex (adjusted OR=0.44; CI, 0.22-0.85), (excellent) quality of physician answers (OR=0.40; CI,0.2-0.77), proximal or mid-ureteric stone (OR=1.9; CI, 1.1-3.5), arrival pain severity (OR=1.18 per unit increase; CI,1.01-1.4), and perceived physician skill (OR=0.81; CI, 0.65-1.0). Patient age, stone size, pain duration, nausea, discharge pain and perceived ED care quality were not independent predictors of 10-day adverse patient experience in multivariate models. Conclusion: Patient sex, quality of physician communication, patient sex, arrival pain severity, and proximal stone location are highly associated with 10-day patient reported AE.

Introduction: NSAIDS offer more effective analgesia than opioids, require less rescue medication, and decrease the incidence of nausea and vomiting in renal colic patients. Alpha blockers and Opioids are also prescribed frequently, but doses used and treatment durations are not well described. Our objective was to investigate ED prescribing decisions and medication compliance by patients with acute renal colic. Methods: In this prospective two-city cohort study, we invited patients with a first ED visit for image-confirmed 2-10 mm ureteric stones to consent to a telephone survey 10 days after their ED visit. During follow-up interviews, patients were asked what drugs they were prescribed and how many doses they required. This study was REB approved. Results: A convenience sample of 224 patients, including 152 males (67.9%) and 72 females (median age= 52.4 years) completed 10-day surveys. NSAIDS were prescribed for 48.7%, tamsulosin for 65.2% and opioids for 81.7%. One-third received a tamsulosin-NSAID combination, 40% an opioid-NSAID combination and 28% a tamsulosin-NSAID-opioid combination. Of 109 patients prescribed an NSAID, only 70 (64.2%) took 1 dose/day; however an additional 28 who were not prescribed NSAIDs took 1 NSAID dose/day. Mean (sd) NSAID intake in the overall study group was 1.1 (1.5) doses/day from day 1-5 and 0.6 (1.1) doses/day on days 6-10, with 90%ile values of 3.0 and 2.0 doses/day. NSAID compliance was more common in patients who stated they received high quality discharge instructions (63.8% vs. 32.6%; RR=1.95; 95% CI 1.47-2.60). Mean opioid intake in the overall study group was 1.2 (1.7) doses/day from day 1-5 and 0.5 (1.3) doses/day on days 6-10, with 90%ile values of 4.0 and 2.0 doses/day. Among patients prescribed tamsulosin, the average was 4.0 days of compliance (sd=4.3), with a 90%ile value of 10 days. Conclusion: This study provides estimates for the amount of drug actually used by renal colic patients during the 10-days after their ED visit. Patients used fewer opioid doses than expected, and NSAID and tamsulosin compliance appears relatively poor. NSAID compliance was better in patients who perceived high quality discharge instructions. This study suggests there is room for improvement in medication prescribing and discharge instructions for ED patients with an acute episode of ureteral colic.

Introduction: CT scan is the most common imaging modality for suspected renal colic and is used for about 80% of presentations. Cumulative ionizing radiation exposure from repeat CT scans increases long-term cancer risk. Despite a 10-fold increase in CT use to detect kidney stones in the ED in just over a decade, there has been no increase in the proportion of kidney stones diagnosed, number of significant alternate diagnoses or admissions to hospital. Choosing Wisely recommends to avoid ordering CT of the abdomen/pelvis in otherwise healthy patients<age 50 presenting to the ED with known history of kidney stones and with symptoms consistent with uncomplicated renal colic. The aim is that >90% of patients < age 50 with a history of renal stones arriving in Sunnybrook ED with symptoms consistent with renal colic will be managed without a CT abdomen/pelvis. Methods: Emergency physicians were engaged in the process at various stages, including a brainstorming session to perform a root cause analysis. A Driver diagram was created to generate change ideas. Outcome Measure Number of CT scans ordered for target population (Results: Results to date indicate that there is a non-sustained decrease in the number of CT scans performed on ED patients < age 50 with recurrent renal colic. The STONE score was infrequently used, thus making it difficult to standardize CT ordering for presumed renal colic. Conclusion: As a result of this QI initiative, there is awareness amongst emergency physicians of a patient population that is over imaged with CT scan, often with no change in management. Introduction of a low dose CT scan order was the greatest gain from this QI initiative. In order to decrease CT utilization, physicians need to be shown the lack of benefit of CT use and a safe alternative diagnostic approach.

Introduction: Computed tomography (CT) has increasingly been used as a standard initial investigation for patients presenting to the Emergency Department (ED) with suspected nephrolithiasis. Compared to ultrasound, CT has increased system-level costs, ionizing radiation exposure and frequently does not alter management. For these reasons, Choosing Wisely (CW) recommends avoiding CT imaging of otherwise healthy patients younger than age 50 years presenting with symptoms of uncomplicated renal colic that have a known history of nephrolithiasis or ureterolithiasis. We aimed to evaluate the degree of utilization of CT imaging for this subgroup of patients in a tertiary care centre ED. Methods: A retrospective chart review was performed for all patients younger than 50 years who visited Sunnybrook Health Sciences Centre ED for six months between December 2015 and May 2016 with renal colic symptoms and a history of nephrolithiasis. Demographic data, relevant past medical history, clinical presentation, lab values, urology consultation, ED treatments administered, diagnostic imaging orders and dispositions were recorded for each eligible patient. Results: Out of 130 reviewed patient charts, 73 patients were identified with a previous history of nephrolithiasis and a presentation consistent with uncomplicated renal colic. 54 patients received ultrasound, KUB x-ray, or no imaging. The other 19 (26.0%) of these patients received an abdominal/pelvic CT with an indication of looking for renal or ureteral stones. Of the patients that received CT, none demonstrated significant findings warranting hospital admission or leading to identifiable changes in ED management. Five (26.3%) of these 19 patients had received a total of three to four CTs for renal colic during past Sunnybrook ED visits, while one had previously received 13 CTs. Conclusion: CT scans are often used as an initial diagnostic modality for suspected renal colic despite a Choosing Wisely recommendation to restrict the use of CT scans in a target population and infrequent changes in management after obtaining a CT. These findings highlight the need for quality improvement strategies to decrease CT utilization in this patient population with suspected renal colic.

Introduction: Most patients with acute renal colic are discharged from the ED after initial diagnosis and symptom control, but 20-30% require repeat ED visits for ongoing pain, and 15-25% require rescue intervention (ureteroscopic intervention or lithotripsy). If patients destined for failure of outpatient management could be identified based on information available during their ED visits, they could be prioritized early for intervention to reduce short term pain and disability. Our objective was to identify predictors of outpatient treatment failure, defined as the need for hospitalization or rescue intervention within 60 days of ED discharge. Methods: We collated prospectively gathered administrative data from all Calgary region patients with an ED diagnosis of renal colic over a one-year period. Demographics, arrival mode, triage category, vital signs, pain scores, analgesic use and ED disposition were recorded. Research assistants reviewed imaging reports and documented stone characteristics. These data were linked with regional hospital databases to identify ED revisits, hospital admissions, and surgical procedures. The primary outcome was hospitalization or rescue intervention within 60 days of ED discharge. Results: Of 3104 patients with first ED visit for acute renal colic, 1296 had CT or US imaging and were discharged without intervention. Median age was 50 years and 69% were male. 325 patients (25.1%) required an ED re-visit and 11.8% required admission or rescue intervention. Patients with small (<5mm), medium (5-7mm) and large (>7mm) stones failed in 9.0%, 14.4% and 9.9% of cases respectively. The only factor predictive of treatment failure in multivariable models was stone position in the proximal or mid-ureter. Age, sex, vital signs, pain score, WBC, creatinine, history of prior stone or intervention, stone side, stone size, presence of stranding and degree of hydronephrosis were not associated with outpatient failure. Conclusion: Outpatient treatment failure could not be predicted based on any of the predictors studied.

Introduction: Patients with renal colic present frequently to the emergency department (ED). Existing literature suggests management with medical expulsion therapy (MET) may improve outcomes, especially for those with stones > 5 mm in size. This study evaluates the use of MET in the management of adult patients seen in regional EDs with a diagnosis of renal colic. Methods: A multi-centered medical chart review study was conducted in seven Edmonton-Zone EDs. Approximately 100 cases from each site were randomly selected from administrative data from the 2014 calendar year, no repeat cases were permitted. Using a standardized data collection process and trained research assistance, data were abstracted from medical charts. Medians and inter-quartile ranges (IQR), proportions, and odds ratios (OR) with 95% confidence intervals (CIs) are reported. Results: Overall, 656 patient charts were included in the review; median age was 46 years (IQR: 35, 46) and 249 (38%) were female. Few (10%) arrived by ambulance or were on MET therapy at presentation; however, many (51%) reported a previous episode of renal colic. Many (191 {29%}) received no initial ED imaging; CT (236 {36%}) was favoured over ultrasound (39 {6%}) for initial imaging, either alone or with plain radiographs (8%). Plain radiographs were frequently ordered (204 {31%}). Only 198 (31%) of charts contained documentation of the use of MET at discharge and the median duration of therapy was 10 days (IQR: 7, 14). Initiation of MET therapy did not vary based on older age (OR = 0.8; 95% CI: 0.57, 1.14); sex (OR = 0.9; 95% CI: 0.67, 1.33); resident involvement (OR = 1.1; 95% CI: 0.63, 2.0); presentation to an academic centre (OR = 1.4; 95% CI: 0.96, 1.95) or stone size (OR = 1.3; 95% CI: 0.76, 2.06). Conclusion: Management of renal colic with MET is uncommon in this region and practice variation appears driven by physician preference rather than evidence. Practice guidelines with standardized order sets are urgently needed to improve care.

Introduction: Hydronephrosis is a marker of stone-related ureteral obstruction. Our objective was to assess the diagnostic and prognostic value of hydronephrosis in ED patients with renal colic. Methods: We used an administrative database to identify all renal colic patients seen in Calgary’s four EDs in 2014. Research assistants reviewed imaging reports to identify proven ureteral stones, and to document hydronephrosis and stone size. Surgical interventions, ED and hospital visits within 60-days were collated from all regional hospitals. The primary outcome was sensitivity and specificity of hydronephrosis (moderate or severe) for detecting stones >5mm. We also assessed the association of hydronephrosis with index admission-intervention, and with outcomes at 7 and 60 days. Results: In 2014, 1828 patients had a confirmed ureteral stone plus assessment of hydronephrosis and stone size (1714 CT, 114 US). Hydronephrosis was absent, mild, moderate or severe in 15%, 47%, 34% and 4% of patients respectively. Median stone size was 4.0, 4.0, 5.0 and 7.0mm for patients in these categories. Mild, moderate and severe hydronephrosis were highly associated with admission (OR=2.0, 4.6, 9.8; p<0.001) and index visit surgical intervention (OR=2.1, 3.7, 6.0; p<0.001). The presence of moderate-severe hydronephrosis was 54.7% sensitive and 65.4% specific for stones > 5mm, with positive and negative predictive values of 51% and 74.2%. Of 1828 patients, 748 had an index visit surgical procedure and 1080 were discharged with medical management. In the latter group, hydronephrosis was absent, mild, moderate or severe in 20%, 50%, 27% and 3%. Corresponding median (IQR) stone size was 3.0, 4.0, 4.0 and 5.0mm. Of 1080 medically managed patients, 19% and 25% had an unscheduled ED revisit by 14 and 60 days, 9% and 10% were hospitalized by 7 and 60 days, and 13% had a rescue procedure within 60 days. In the medically managed group, degree of hydronephrosis had no statistical association with any outcomes at 7 or 60 days. Conclusion: Hydronephrosis has poor sensitivity, specificity and predictive value for stones >5mm. Degree of hydronephrosis is highly associated with MD decisions for admission and intervention, but not associated with patient outcomes in the absence of these decisions. Despite poor diagnostic and prognostic performance, hydronephrosis is likely guiding critical early management decisions.