Abstract
INTRODUCTION
Renal colic is a common emergency department (ED) presentation. Variations in assessment and management of suspected renal colic may have significant implications on patient and hospital outcomes. We developed a clinical practice guideline to standardize the assessment and management of renal colic in the ED. We subsequently compared outcomes before and after guideline implementation.
METHODS
The guideline standardizes the analgesia regimen, urology consult criteria, imaging modality, patient education, and followup instructions. This is a single-center, observational cohort study of patients presenting to the ED with renal colic prospectively collected after guideline implementation (December 2018 to May 2019) compared to a control group retrospectively collected before guideline implementation (December 2017 to May 2018). A total of 528 patients (pre-guideline n=283, post-guideline n=245) were included. Statistical analysis was performed with SPSS using multivariate linear regression.
RESULTS
ED length of stay (LOS) was significantly shorter after guideline implementation (pre-guideline 295.82±178.8 minutes vs. post-guideline 253.2±118.2 minutes, p=0.017). The number of computed tomography (CT) scans patients received was significantly less after guideline implementation (pre guideline 1.35±1.34 vs. post-guideline 1.00±0.68, p=0.034). Patients discharged for conservative management had a lower re-presentation rate in the post-guideline group (12.6%) than the pre-guideline group (17.2%); however, this did not reach statistical significance (p=0.18).
CONCLUSIONS
Implementation of a clinical practice guideline for ureteric stones reduces the ED LOS and the total number of CT scan in patients who present with renal colic. Standardizing assessment and management of ureteric stones can potentially improve patient and hospital outcomes without compromising the quality of care.
INTRODUCTION
Renal colic is a common emergency department (ED) presentation. Lifetime risk of urolithiasis is 12% in men and 6% in women.1 Despite the high incidence, there are no existing universal clinical practice guidelines at a local or national level and very few international guidelines.2,3 Subsequent variations in assessment and management of suspected renal colic may have implications on patient and hospital outcomes, particularly quality and cost of care. We developed a clinical practice guideline for our local health district to standardize the assessment and management of ureteric stones in the ED. To the best of our knowledge, there is no literature reporting the benefits and improvements in quality of care after best practice guideline implementation. The aim of this study was to compare patient and hospital outcomes prior to and following implementation of a clinical practice guideline for ureteric stones.
METHODS
Clinical practice guideline
The clinical practice guideline (Figure 1) (Appendix; available at cuaj.ca) was developed to standardize assessment and management of renal colic with best evidence-based practice. The guideline was developed in consultation with the urology, emergency medicine, and radiology departments. The guideline was mandatory to follow. ED staff received in-person education on the guideline and electronic and physical copies were made easily accessible.
Figure 1.
Emergency department flowchart for first presentation of renal colic.
The guideline recommends a standardized analgesia regimen of paracetamol, indomethacin, and oxycodone as required. The imaging modality was standardized so that all patients with computed tomography (CT)-confirmed stones received an X-ray. For those with radio-opaque stones visible on X-ray, X-ray was used as the followup imaging modality to minimize radiation exposure. Patients with stones not visible on X-ray received CT of the kidney-ureter-bladder (KUB) as their subsequent followup imaging. The urology consult criteria were streamlined, including signs of sepsis, stone size >5 mm, multiple or bilateral ureteric stones, solitary or transplant kidney, or creatinine >200 μmol/L. For patients who met discharge criteria for conservative management, patient and general practitioner factsheets were developed to standardize patient education and followup instructions for analgesia and repeat imaging in 4–6 weeks to ensure stone passage. These factsheets were translated from English into Vietnamese, Arabic, and Chinese — the four most spoken languages in the local health district.
Study population
This was a single-center, quality-improvement study. We performed an observational cohort study of consecutive patients presenting to the ED of a metropolitan teaching hospital with renal colic between December 2018 and May 2019, prospectively collected after guideline implementation. A control group of patients were retrospectively collected prior to guideline implementation between December 2017 to May 2018, in a time matched period to account for the seasonal variations on incidence of renal colic.4 Patients who were <18 years of age or pregnant were excluded from the study. The study was approved by the South Western Sydney Local Health District Human Research Ethics Committee (ETH09934).
Statistical analysis
IBM SPSS Statistics® version 28 (IBM®, Armonk, U.S.) was used for the statistical analysis. Continuous variables were reported as mean (standard deviation) or median (interquartile range), whereas categorical variables were expressed in total number (percentage) as appropriate. Depending on the assumption of normal distribution, continuous variables between pre- and post-guideline groups were compared using independent t-test or Mann-Whitney U test. In addition, multivariate linear regression was performed to identify risk factors of length of stay (LOS) in ED and total number of CT scans. Regression coefficient and its 95% confidence interval (CI) were calculated.
RESULTS
A total of 528 patients were included in this study. There were 283 patients in the pre-guideline group and 245 patients in the post-guideline group. The patient demographics and clinical characteristics are summarized in Table 1. The mean age was 47.8±15.0 years and 24.1% of subjects were female. The post-guideline group had a significantly higher percentage of X-ray and stone identified on X-ray (Table 1).
Table 1.
Patient demographics and clinical characteristics
| Mean ± SD or n (%) | p | |||
|---|---|---|---|---|
| Pre-guideline | Post-guideline | Total | ||
|
| ||||
| Age (years) | 48.5±15.0 | 47.0±15.0 | 47.8±15.0 | 0.28 |
|
| ||||
| Female | 64 (22.6%) | 63 (25.7%) | 127 (24.1%) | 0.41 |
|
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| X-ray in ED | 17 (6.0%) | 142 (58.2%) | 159 (30.2%) | <0.0001* |
|
| ||||
| Stone on X-ray | 11 (73.3%) | 60 (42.3%) | 71 (45.2%) | 0.028* |
|
| ||||
| Stone size on X-ray | 3.80±1.30 | 3.69±2.68 | 3.70±2.56 | 0.93 |
|
| ||||
| CT in ED | 217 (76.7%) | 195 (79.6%) | 412 (78.0%) | 0.42 |
|
| ||||
| Stone on CT | 174 (81.3%) | 154 (79.8%) | 328 (80.6) | 0.70 |
|
| ||||
| Stone size on CT | 4.0 (3.0–7.0) | 4.0 (3.0–6.0) | 4.0 (3.0–6.0) | 0.065 |
|
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| Alternative findings on CT | 4 (2.4%) | 5 (4.0%) | 9 (3.0%) | 0.42 |
|
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| Incidental CT findings | 47 (26.9%) | 39 (23.2%) | 86 (25.1%) | 0.44 |
|
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| Ultrasound in ED | 14 (5.0%) | 10 (4.1%) | 24 (4.6%) | 0.64 |
|
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| Urology consult criteria | 0.34 | |||
| No | 159 (69.1%) | 180 (76.3%) | 339 (72.7%) | |
| Signs of sepsis | 5 (2.2%) | 1 (0.4%) | 6 (1.3%) | |
| Stone >5 mm | 51 (22.2%) | 45 (19.1%) | 96 (20.6%) | |
| >1 stone in ureter | 4 (1.7%) | 1 (0.4%) | 5 (1.1%) | |
| Bilateral stones | 3 (1.3%) | 2 (0.8%) | 5 (1.1%) | |
| Creatinine >200 | 5 (2.2%) | 3 (1.3%) | 8 (1.7%) | |
| Intractable pain | 3 (1.3%) | 4 (1.7%) | 7 (1.5%) | |
Statistically significant.
Results are expressed as mean ± standard deviation, median (interquartile range) or number (percentage). CT: computed tomography; ED: emergency department; SD: standard deviation.
The mean ED LOS (time from ED presentation to discharge or ward admission) was 295.82±178.8 minutes in the pre-guideline group and 253.2±118.2 minutes in the post-guideline group. The ED LOS was significantly shorter after guideline implementation (mean difference 0.72, 95% CI 0.29–1.14, p=0.017) (Figure 2A, Table 2). The association between guideline implementation and ED LOS was statistically significant (p=0.022) after controlling for age, gender, X-ray in ED, ultrasound in ED, does not meet urology consult criteria, and urology consult for stone >5 mm (Table 3). Moreover, ultrasound in ED was associated with longer ED LOS (p=0.001).
Figure 2.
Control charts showing: (A) emergency department (ED) length of stay; and (B) total number of computed tomography (CT) scans per patient. LCL: lower control limit; UCL: upper control limit.
Table 2.
Comparison of outcomes before and after clinical practice guideline implementation
| Pre-guideline | Post-guideline | Total | p | |
|---|---|---|---|---|
|
| ||||
| ED LOS | 0.017* | |||
| Mean ± SD | 4.93±2.98 | 4.22±1.97 | 4.60±2.59 | |
| Median (IQR) | 3.92 (3.12–5.98) | 3.73 (2.79–5.21) | 3.83 (2.92–5.57) | |
|
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| Admission, n (%) | 67 (23.8%) | 62 (25.4%) | 129 (24.5%) | 0.66 |
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| Surgery, n (%) | 44 (15.5%) | 39 (21.2%) | 83 (17.8%) | 0.12 |
|
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| Time to surgery | n=38 | n=37 | 0.094 | |
| Mean ± SD | 24.5±34.0 | 24.6±15.0 | 24.5±26.2 | |
| Median (IQR) | 15.5 (4.50–32.0) | 23 (14.0–28.5) | 20.0 (8.0–30.0) | |
|
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| Hospital LOS, mean ± SD | 1.74±1.38 | 1.92±1.14 | 1.81±1.29 | 0.43 |
|
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| Re-presentation, n (%) | 41 (17.2%) | 26 (12.6%) | 67 (15.1%) | 0.18 |
|
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| Total number of CT scans | 0.034* | |||
| Mean ± SD | 1.35±1.34 | 1.00±0.68 | 1.19±1.10 | |
| Median (IQR) | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) | |
Statistically significant.
Results are expressed as mean ± standard deviation, median (interquartile range) or number (percentage). CT: computed tomography; IQR: interquartile range; LOS: length of stay; SD: standard deviation.
Table 3.
Multivariate linear regression analysis of emergency department length of stay and total number of CT scans
| Length of stay in ED | Total number of CT scans | |||
|---|---|---|---|---|
| Coefficient (95% CI) | p | Coefficient (95% CI) | p | |
|
| ||||
| Guideline | −0.64 (−1.18 to −0.092) | 0.022* | −0.42 (−0.65 to −0.19) | <0.0001* |
|
| ||||
| Age | 0.58 | 0.35 | ||
|
| ||||
| Gender | 0.82 | 0.95 | ||
|
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| X-ray in ED | 0.68 | 0.14 | ||
|
| ||||
| Ultrasound in ED | 1.77 (2.85 to 0.68) | 0.001* | 0.95 | |
|
| ||||
| Does not meet urology consult criteria | 0.82 | 0.65 | ||
|
| ||||
| Urology consult for stone >5 mm | 0.64 | 0.16 | ||
Statistically significant.
CI: confidence interval; CT: computed tomography; ED: emergency department.
The mean total number of CT scans patients received over the course of their care was 1.35±1.34 in the pre-guideline group and 1.00±0.68 in the post-guideline group. There was a significant reduction in the number of CT scans in the post-guideline group (mean difference 0.35, 95% CI 0.17–0.53, p=0.034) (Figure 2B, Table 2). The association between guideline implementation and total number of CT scans remained significant (p<0.0001) after controlling for age, gender, X-ray in ED, ultrasound in ED, does not meet urology consult criteria, and urology consult for stone >5 mm (Table 3).
There were no differences in admission rate (p=0.66), surgery rate (p=0.12), time to surgery (p=0.094), hospital LOS (p=0.43), and re-presentation to ED (p=0.18) between the pre- and post-guideline groups.
Patients discharged for conservative management of a ureteric stone had a lower rate of representation in the post-guideline group (12.6%) compared with the pre-guideline group (17.2%); however, this did not reach statistical significance (p=0.18).
DISCUSSION
To the best of our knowledge, our study is the first to demonstrate the effects of best evidence guideline implementation for renal colic on ED LOS. Managing overcrowding in ED and shortening ED LOS, without compromising patient care, is an important target for any public healthcare system. It has been reported that extended stay in the ED results in increased inpatient mortality rate up to 30 days post-admission.5 Our findings show that this guideline reduced ED LOS by 42 minutes. This is a clinically significant reduction in the LOS, given the state-based Emergency Treatment Performance target aims for patients to be admitted, transferred, or discharged from the ED within four hours.6 A reduced ED LOS has benefits for both patients and the healthcare system. For patients, there were lower rates of left-without-being-seen, ED mortality, inpatient mortality, and 30-day mortality.7,8 At an institutional level, a reduction in ED LOS reduces hospital spending.9 Unfortunately, these outcomes were not measured in our study.
Furthermore, our guideline was found to reduce the total number of CT scans a patient receives over the course of their care. Non-contrast CT-KUB is the gold-standard imaging modality for renal colic.2 Patients often receive more than one CT-KUB during the course of their acute illness. Broder et al reported 74% of patients who presented with renal colic received a CT scan and 79% had more than two scans.10 Furthermore, the majority of patients will have stone recurrence within five years of an initial stone.11 This raises concerns regarding potential health impacts associated with radiation exposure. Although low-dose or ultra-low-dose CT-KUB can be used with preserved sensitivity and specificity,12 cumulative radiation exposure may increase overall lifetime risk of malignancy by 0.7%.13
Followup imaging is essential to ensure passage of the stone. Patients with ureteric stones who do not report stone passage and do not receive followup imaging are at risk of silent obstruction, whereby the presence of renal obstruction is painless.14–16 Plain X-ray KUB is able to identify radiopaque stones, which account for upwards of 60% of stones.17 Therefore, X-ray KUB may be a suitable followup imaging modality for patients with radiopaque stones, as it may reduce radiation dose by 7–14-fold.18
Our guideline recommends dual initial imaging modalities (CT-KUB and plain X-ray KUB) to identify patients with radio-opaque stones who can then be followed up solely with plain X-ray KUB. Our study has shown that this reduces the number of CT scans by 0.35 total scans, on average, per patient without any significant changes in the admission rate, time to surgery, hospital LOS, and re-presentation rate. As such, our guideline may reduce unnecessary radiation exposure without compromising patient safety.
Many patients can be discharged safely from the ED for conservative management, as approximately 80% of ureteric stones pass spontaneousl;19 however, a significant proportion of patients discharged home to await stone passage often re-present to the ED due to inadequate pain management or a misunderstanding of their conservative management plan. To reduce ED re-presentations, we streamlined conservative management by standardizing the analgesia regimen to ensure all patients are discharged with sufficient analgesia.
Poor health literacy and language barriers lead to poor adherence to medication instructions, higher hospital re-presentation rates, and poorer health outcomes.20–22 This is particularly prevalent in our institution, as the catchment area includes a large proportion of culturally and linguistically diverse patients, with 62% of residents speaking a language other than English at home.23 We endeavoured to provide culturally competent care and improve health literacy by developing patient and GP factsheets, available in English, Arabic, Chinese, and Vietnamese for patients discharged for conservative management of a ureteric stone. These strategies lead to a lower re-presentation rate in the post-guideline group (12.6%) than in the pre-guideline group (17.2%).
Our study found that the use of ultrasound KUB was associated with a longer ED LOS. Ultrasound KUB is performed as a formal ultrasound in the radiology department at our institution, hence, there can be delays in obtaining an ultrasound due to awaiting allocated appointment slots and transfer to the radiology department. Furthermore, ultrasound has limited sensitivity of 70.2% and specificity of 75.4% for ureteric stones, which may influence treatment decisions.24,25 Hydronephrosis is not an accurate predictor of the presence or passage of ureteric stones, with no hydronephrosis in 18% of patients presenting with renal colic and 60% of patients with a persistent stone at followup CT.16 While point-of-care ultrasound may be a useful adjunct to identify patients with hydronephrosis and streamline them to immediately proceed to a CT scan, it should only be performed by appropriately accredited staff and should not routinely replace CT as the imaging modality of choice. Hence, POCUS was not included in the assessment algorithm of our guideline unless patients were pregnant.
Limitations
There were several limitations in our study. This study was conducted in a tertiary hospital in a metropolitan Australian center. There may be variations due to institutional or geographic factors and a multicenter study should be considered to confirm our findings. We plan to do so once we have implemented this clinical practice guideline across other hospitals in the local health district. Our clinical practice guideline standardizes several parameters in the assessment and management of renal colic. It is difficult to pinpoint which of these specifically led to the improvements in hospital and patient outcomes. Furthermore, outcomes such as morbidity and mortality rate and cost analysis were not included in this study. These are important parameters in determining the efficiency of any intervention implemented in a healthcare system.
CONCLUSIONS
The implementation of a clinical practice guideline for ureteric stones reduces the ED LOS and the total number of CT scans in patients who present with renal colic. Standardizing the assessment and management of ureteric stones can potentially improve patient and hospital outcomes without compromising the quality of care.
KEY MESSAGES
■ Implementation of a clinical practice guideline for ureteric stones reduces ED length of stay and the total number of CT scans a patient receives on average over the course of their acute illness.
■ Standardizing assessment and management of ureteric stones can potentially improve patient and hospital outcomes without compromising the quality of care.
Supplementary Information
Footnotes
Appendix available at cuaj.ca
COMPETING INTERESTS: The authors do not report any competing personal or financial interests related to this work.
This paper has been peer-reviewed.
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