The Journal of Emergency Medicine, Vol. 48, No. 1, pp. 53–57, 2015 Copyright Ó 2015 Elsevier Inc. Printed in the USA. All rights reserved 0736-4679/$ - see front matter
http://dx.doi.org/10.1016/j.jemermed.2014.07.033
Selected Topics: Emergency Radiology
IMPACT OF AN EMERGENCY MEDICINE DECISION SUPPORT AND RISK EDUCATION SYSTEM ON COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING USE Tony J. Carnevale, MD,* Di Meng, PHD,† James J. Wang,† and Mark Littlewood, MPA‡ *Kaiser Permanente Northwest Sunnyside Medical Center, Portland, Oregon, †Health Information Technology Transformation and Analytics, Kaiser Permanente, Oakland, California, and ‡Risk Management and Patient Safety, The Permanente Federation, Oakland, California Reprint Address: Di Meng, PHD, Health Information Technology Transformation and Analytics, Kaiser Permanente, 1800 Harrison Street, Oakland, CA 94612
, Keywords—computed tomography; magnetic resonance imaging; quality improvement; utilization; clinical decision support systems
, Abstract—Background: Increasing computed tomography (CT) and magnetic resonance imaging (MRI) use in the emergency department (ED) over the last decade is well documented. Objective: Our aim was to assess the impact of an electronic decision support and risk education system (DS-RES) on CT/MRI use. Methods: We conducted an age-, sex-, and risk-adjusted analysis of CT/MRI use and ED and inpatient rebound rates before and after implementation in 2009 at a Kaiser Permanente Northwest medical center. Results: In the pre period, a total of 12,531 encounters occurred for unique patients within each of 10 chief complaint categories. In the post period, 16,864 total encounters occurred for unique patients within each chief complaint category, 11.4% of patients were at low risk and 24.8% and 63.8% were at medium and high risk, respectively. Adjusted CT/MRI use increased 1.1% (95% confidence interval [CI] 0%–2.3%) between pre and post periods. Among low-risk and medium-risk patients, CT/MRI use decreased by 5.0% (95% CI 2.5%–7.5%) and 10.4% (95% CI 7.9%–12.8%). Among patients at high risk, CT/MRI use increased by 3.9% (95% CI 2.5%–5.3%). The proportion of patients with a 3- or 7-day rebound to the ED or an inpatient facility decreased between pre and post periods by 1.4% (95% CI 0.7%–2.2%) and 0.7% (95% CI 0.2%–1.5%). Conclusions: DS-RES implementation did not decrease overall CT/MRI rates, but it was associated with a shift in use toward highrisk patients and less patient rebound to the ED and hospital. Further research is required to identify mechanisms underlying imaging utilization shifts. Ó 2015 Elsevier Inc.
INTRODUCTION Increasing rates of imaging during emergency department (ED) visits in the last decade are well documented (1–9). Approximately 16% of ED visits nationwide include computed tomography (CT) or magnetic resonance imaging (MRI) (10). Other estimates suggest a similar percentage for CT scans alone in adult ED visits (11). Increased use of imaging prolongs length of stay in the ED, confers little or no additional clinical benefit, and raises concerns about radiation exposure (12–18). The ED is the only setting in which the use of CT scans among the Medicare population failed to decrease between 2000 and 2010 (19). Reported strategies to decrease overuse of imaging in the ED include preauthorization and real-time reminders on radiology requisitions, which variably impact utilization (20–22). Health-information exchange reduced neuroimaging in repeat ED visits by patients with headache (23). Clinical guidelines can potentially decrease the use of CT imaging by as much as 35%, although this suggestion has not been validated (12).
RECEIVED: 28 August 2013; FINAL SUBMISSION RECEIVED: 29 May 2014; ACCEPTED: 1 July 2014 53
54
T. J. Carnevale et al.
Our objective in this quality-improvement project was to assess the impact of a multimodal emergency medicine decision support and risk education system (DS-RES) on the use of CT and MRI imaging. METHODS
system for the listed complaints ranged from 64.3% to 95.5%. Overall, physicians used DS-RES in 81.6% of encounters for these complaints. We designated the pre period as July 2008 to June 2009 and the post period as October 2009 through September 2010.
Emergency Medicine DS-RES
Statistical Analysis
DS-RES focuses on the diagnostic process in the ED with the goal of eliminating diagnostic delays and errors. It is based on a foundation of sound risk-reduction principles and includes point-of-care decision support tools in an integrated electronic health record (EHR), online riskreduction training, and regular feedback to physicians and nurses about their documentation performance using the EHR decision support tools (Figure 1). DS-RES templates for certain conditions include multiple alerts, key information (eg, identification of conditions as high risk, risk factors), documentation and flowsheet templates, order sets and order entry, trackboards to follow patient status and ordered/completed testing, and discharge documentation.
Data were available at three levels: encounter, chief complaint, and patient. Encounters during the pre and post periods included multiple visits from the same patients for one or more chief complaints. We examined imaging utilization at the level of encounters because each encounter represented an imaging opportunity. After excluding patients with a second or subsequent encounter for the same chief complaint, we adjusted encounters that occurred before and after DS-RES implementation for patient-level age, sex, and risk status. The latter was measured by DxCG score (Verisk Health,Inc.,Waltham, MA) and categorized into one of three risk groups: low (DxCG < 1), middle (DxCG $ 1 and < 5), and high (DxCG $ 5). We segmented the patient population with post-implementation encounters into these risk groups and divided the pre-implementation encounters into a similar risk distribution to adjust for these factors. We measured imaging utilization by physician orders and assessed the statistical significance of differences between the pre and post periods with the Z-test. We repeated this analysis after excluding encounters in which the chief complaints seemed least likely to require an order for imaging: fever in a child, laceration, and vaginal bleeding. We also assessed the proportion of 3- and 7-day rebound visits in the pre and post periods, similarly adjusting for age, sex, and risk status. Rebound was defined as a return visit to the ED or admission to an inpatient facility.
Design, Setting, and Population We conducted an age-, sex-, and risk-adjusted analysis of CT/MRI use and rebound rates before and after implementation of DS-RES. The medical center began using DS-RES in July 2009. Among patients who were not subsequently transferred to the hospital, we analyzed ED encounters for 10 chief complaints: abdominal pain, chest pain, fever in children, headache, head injury, laceration, lower and upper extremity injury, neck injury, shortness of breath, and vaginal bleeding. Provider use of DSRES was voluntary; excluding fever in children, the proportion of ED encounters in which physicians used the
Figure 1. Decision support and risk education system (DS-RES) screenshot. DS-RES provides documentation templates and point-of-care decision supports, as in this screenshot.
Impact of DS-RES on Imaging Use
55
Table 1. Distribution of All Encounters by Chief Complaint Chief Complaint
Pre DS-RES (n = 18,105)
Post DS-RES (n = 20,892)
Abdominal pain Chest pain Fever in a child Head injury Headache Laceration Lower extremity injury Neck injury Shortness of breath Upper extremity injury Vaginal bleeding
4879 3676 1153 589 1552 1492 342 346 2538 1061 477
5455 4522 1466 642 1686 1493 657 387 3025 1104 455
DS-RES = decision support and risk education system. Encounters include multiple patient visits for the same chief complaint.
RESULTS In the pre period, a total of 18,105 encounters occurred for patients with all chief complaints listed here; in the post period, 20,892 encounters occurred (Table 1). After excluding second or subsequent encounters for the same patient and chief complaint, a total of 12,531 encounters occurred in the pre period and 16,864 encounters occurred in the post period. The total number of unique patients across all chief complaints was 10,856 in the pre period and 14,834 in the post period (Table 2). The proportions of these patients in the low-, medium-, and high-risk groups were 11.4%, 24.8%, and 63.8%, respectively. In the pre period, the adjusted CT/MRI rate was 26.0%; in the post period, the comparable rate was 28.3% (p < 0.0001). Patterns of use shifted. Among enTable 2. Characteristics of Unique Patients With Encounters Related to All Chief Complaints
Male sex (%) Age (%) Younger than 20 y 21 44 y 45 64 y 65 y or older Race/ethnicity, % Non-Hispanic White Asian/Pacific Islander Black Latino Native American Other Unknown Risk status, DxCG score (%) 5
Pre DS-RES (n = 10,856)
Post DS-RES (n = 14,834)
43.6
43.4
16.2 27.7 33.0 23.1
17.2 27.5 32.0 23.4
75.4 4.9
77.2 4.6
4.6 4.4 1.1 2.6 6.9
5.3 5.7 0.8 1.9 4.5
10.7 27.9 61.4
8.6 25.1 66.3
DS-RES = decision support and risk education system.
counters in which patients were in the low-risk group, CT/MRI use decreased by 6.2% (95% confidence interval [CI] 4.0%–8.5%). Imaging use also decreased 3.3% (95% CI 1.6%–5.0%) in encounters involving medium-risk patients. However, in encounters with patients at high risk, the use of CT or MRI scans increased by 5.6% (95% CI 4.3%–7.0%). After excluding encounters related to fever in a child, laceration, and vaginal bleeding, CT/MRI use in encounters with low- and high-risk patients changed only minimally; use in encounters with medium-risk patients decreased by an additional 7 percentage points to 10.4% (95% CI 7.9%–12.8%). The proportion of patients with a 3-day rebound visit to either the ED or to an inpatient facility decreased between the pre and post periods by 1.4% (95% CI 0.7%–2.2%) from 9.7% to 8.3%. The proportion of patients with a 7-day rebound also decreased by 0.7% (95% CI 0.2% to 1.5%), from 13.9% to 13.2%. DISCUSSION Although imaging rates did not decrease after the implementation of an emergency medicine decision support and risk education system, patterns of use did shift to a statistically significant degree. A lower proportion of patients in the low- and medium-risk groups and a higher proportion of patients in the high-risk group had imaging tests after DS-RES implementation. In addition, 3- and 7day rebound rates decreased between the pre- and postimplementation periods. Strengths of our project include that it documents a shift in imaging utilization associated with risk groups, in addition to overall patterns of use. Potential explanations for the observed variation in use by risk include improved diagnostic processes resulting in less overuse of imaging among lower-risk patients and appropriately increased use among higher-risk patients. Another strength of our project is that, although we assessed a single ED, the population was relatively large. Our results are consistent with other reports of the difficulty of reducing overall imaging use in the ED (19,22). They also suggest that estimated potential reductions in imaging use by more than one third after implementation of clinical guidelines may be unduly optimistic (12). However, absolute decreases might not be an appropriate goal. Our findings suggest that our baseline imaging rates included both overuse among low- and medium-risk patients and underuse among high-risk patients. Depending on the proportion of each that is occurring in a given location or system, increasing the appropriateness of imaging utilization may have a variable effect on overall rates. However, additional research is needed to confirm the clinical impact of the shift in CT/MRI utilization we noted.
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T. J. Carnevale et al.
Limitations One limitation of our quality-improvement project is the observational nature of our assessment. We controlled for potential confounders, such as age, sex, and disease burden, but other, unmeasured variables may have impacted our findings. We performed an aggregate mixed-model adjustment, which did not take into account any variations in the mix of chief complaints between the two periods; we assumed that chief complaints varied randomly during the two observation periods. We were also unable to directly measure diagnostic accuracy, an organizational goal of implementing DS-RES. The decrease in the 7-day rebound rate was not statistically significant. Decreased rebound rates suggest that fewer patients had unaddressed needs after an ED visit in the post period, which is likely to be a function, at least in part, of increased diagnostic accuracy. However, these data remain suggestive, and further study is required to understand the mechanisms underlying lower rebound rates and to identify any role played by increased diagnostic accuracy. CONCLUSIONS Implementation of an emergency medicine decision support and risk education initiative did not decrease overall CT/MRI rates in ED visits, but it was associated with a shift in utilization toward high-risk patients. We conclude that baseline imaging rates included components of both over- and underuse by risk group; concomitant decreases in rebound rates suggest greater diagnostic accuracy. REFERENCES 1. Korley FK, Pham JC, Kirsch TD. Use of advanced radiology during visits to US emergency departments for injury-related conditions, 1998-2007. JAMA 2010;304:1465–71. 2. Broder J, Warshauer DM. Increasing utilization of computed tomography in the adult emergency department, 2000-2005. Emerg Radiol 2006;13:25–30. 3. Larson DB, Johnson LW, Schnell BM, et al. National trends in CT use in the emergency department: 1995-2007. Radiology 2011;258: 164–73. 4. Prologo JD, Gilkeson RC, Diaz M, et al. CT pulmonary angiography: a comparative analysis of the utilization patterns in emergency department and hospitalized patients between 1998 and 2003. AJR Am J Roentgenol 2004;183:1093–6.
5. Raja AS, Mortele KJ, Hanson R, et al. Abdominal imaging utilization in the emergency department: trends over two decades. Int J Emerg Med 2011;4:19. 6. Boone JM, Brunberg JA. Computed tomography use in a tertiary care university hospital. J Am Coll Radiol 2008;5:132–8. 7. Friedman BW, Chilstrom M, Bijur PE, Gallagher EJ. Diagnostic testing and treatment of low back pain in United States emergency departments: a national perspective. Spine 2010;35:E1406–11. 8. Gilbert JW, Johnson KM, Larkin GL, Moore CL. Atraumatic headache in US emergency departments: recent trends in CT/MRI utilisation and factors associated with severe intracranial pathology. Emerg Med J 2012;29:576–81. 9. Pines JM, Mullins PM, Cooper JK, et al. National trends in emergency department use, care patterns, and quality of care of older adults in the United States. J Am Geriatr Soc 2013;61:12–7. 10. Freid VM, Bernstein AB. Health care utilization among adults aged 55-64 years: how has it changed over the past 10 years? NCHS Data Brief 2010;1–8. 11. Kirsch TD, Hsieh YH, Horana L, et al. Computed tomography scan utilization in emergency departments: a multi-state analysis. J Emerg Med 2011;41:302–9. 12. Melnick ER, Szlezak CM, Bentley SK, et al. CT overuse for mild traumatic brain injury. Jt Comm J Qual Patient Saf 2012;38:483–9. 13. Kocher KE, Meurer WJ, Desmond JS, Nallamothu BK. Effect of testing and treatment on emergency department length of stay using a national database. Acad Emerg Med 2012;19:525–34. 14. Broder J, Fordham LA, Warshauer DM. Increasing utilization of computed tomography in the pediatric emergency department, 2000-2006. Emerg Radiol 2007;14:227–32. 15. Pines JM. Trends in the rates of radiography use and important diagnoses in emergency department patients with abdominal pain. Med Care 2009;47:782–6. 16. Heller MT, Kanal E, Almusa O, et al. Utility of additional CT examinations driven by completion of a standard trauma imaging protocol in patients transferred for minor trauma. Emerg Radiol 2014;21: 341–7. 17. Shah KH, Slovis BH, Runde D, et al. Radiation exposure among patients with the highest CT scan utilization in the emergency department. Emerg Radiol 2013;20:485–91. 18. Kharbanda AB, Flood A, Blumberg K, Kreykes NS. Analysis of radiation exposure among pediatric trauma patients at national trauma centers. J Trauma Acute Care Surg 2013;74:907–11. 19. Levin DC, Rao VM, Parker L. The recent downturn in utilization of CT: the start of a new trend? J Am Coll Radiol 2012;9:795–8. 20. Blachar A, Tal S, Mandel A, et al. Preauthorization of CT and MRI examinations: assessment of a managed care preauthorization program based on the ACR appropriateness criteria and the Royal College of Radiology guidelines. J Am Coll Radiol 2006; 3:851–9. 21. Stiell IG, Clement CM, Grimshaw J, et al. Implementation of the Canadian C-spine rule: prospective 12 centre cluster randomised trial. BMJ 2009;339:b4146. 22. Stiell IG, Clement CM, Grimshaw JM, et al. A prospective clusterrandomized trial to implement the Canadian CT head rule in emergency departments. CMAJ 2010;182:1527–32. 23. Bailey JE, Wan JY, Mabry LM, et al. Does health information exchange reduce unnecessary neuroimaging and improve quality of headache care in the emergency department? J Gen Intern Med 2013;28:176–83.
Impact of DS-RES on Imaging Use
ARTICLE SUMMARY 1. Why is this topic important? Increased use of computed tomography (CT) and magnetic resonance imaging (MRI) in the emergency department is well documented. The emergency department is the only setting in which the use of CT in the Medicare population failed to decrease between 2000 and 2010. 2. What does this study attempt to show? We assess the impact of an emergency medicine risk decision support and risk education system that included comprehensive point-of-care decision support on CT/ MRI use. 3. What are the key findings? Overall imaging rates increased. However, CT/MRI rates decreased among low- and medium-risk patients and increased among high-risk patients. 4. How is patient care impacted? High rates of CT and MRI use may reflect elements of underuse among high-risk patients and overuse among low- and medium-risk patients.
57
http://dx.doi.org/10.1016/j.jemermed.2014.07.033
Selected Topics: Emergency Radiology
IMPACT OF AN EMERGENCY MEDICINE DECISION SUPPORT AND RISK EDUCATION SYSTEM ON COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING USE Tony J. Carnevale, MD,* Di Meng, PHD,† James J. Wang,† and Mark Littlewood, MPA‡ *Kaiser Permanente Northwest Sunnyside Medical Center, Portland, Oregon, †Health Information Technology Transformation and Analytics, Kaiser Permanente, Oakland, California, and ‡Risk Management and Patient Safety, The Permanente Federation, Oakland, California Reprint Address: Di Meng, PHD, Health Information Technology Transformation and Analytics, Kaiser Permanente, 1800 Harrison Street, Oakland, CA 94612
, Keywords—computed tomography; magnetic resonance imaging; quality improvement; utilization; clinical decision support systems
, Abstract—Background: Increasing computed tomography (CT) and magnetic resonance imaging (MRI) use in the emergency department (ED) over the last decade is well documented. Objective: Our aim was to assess the impact of an electronic decision support and risk education system (DS-RES) on CT/MRI use. Methods: We conducted an age-, sex-, and risk-adjusted analysis of CT/MRI use and ED and inpatient rebound rates before and after implementation in 2009 at a Kaiser Permanente Northwest medical center. Results: In the pre period, a total of 12,531 encounters occurred for unique patients within each of 10 chief complaint categories. In the post period, 16,864 total encounters occurred for unique patients within each chief complaint category, 11.4% of patients were at low risk and 24.8% and 63.8% were at medium and high risk, respectively. Adjusted CT/MRI use increased 1.1% (95% confidence interval [CI] 0%–2.3%) between pre and post periods. Among low-risk and medium-risk patients, CT/MRI use decreased by 5.0% (95% CI 2.5%–7.5%) and 10.4% (95% CI 7.9%–12.8%). Among patients at high risk, CT/MRI use increased by 3.9% (95% CI 2.5%–5.3%). The proportion of patients with a 3- or 7-day rebound to the ED or an inpatient facility decreased between pre and post periods by 1.4% (95% CI 0.7%–2.2%) and 0.7% (95% CI 0.2%–1.5%). Conclusions: DS-RES implementation did not decrease overall CT/MRI rates, but it was associated with a shift in use toward highrisk patients and less patient rebound to the ED and hospital. Further research is required to identify mechanisms underlying imaging utilization shifts. Ó 2015 Elsevier Inc.
INTRODUCTION Increasing rates of imaging during emergency department (ED) visits in the last decade are well documented (1–9). Approximately 16% of ED visits nationwide include computed tomography (CT) or magnetic resonance imaging (MRI) (10). Other estimates suggest a similar percentage for CT scans alone in adult ED visits (11). Increased use of imaging prolongs length of stay in the ED, confers little or no additional clinical benefit, and raises concerns about radiation exposure (12–18). The ED is the only setting in which the use of CT scans among the Medicare population failed to decrease between 2000 and 2010 (19). Reported strategies to decrease overuse of imaging in the ED include preauthorization and real-time reminders on radiology requisitions, which variably impact utilization (20–22). Health-information exchange reduced neuroimaging in repeat ED visits by patients with headache (23). Clinical guidelines can potentially decrease the use of CT imaging by as much as 35%, although this suggestion has not been validated (12).
RECEIVED: 28 August 2013; FINAL SUBMISSION RECEIVED: 29 May 2014; ACCEPTED: 1 July 2014 53
54
T. J. Carnevale et al.
Our objective in this quality-improvement project was to assess the impact of a multimodal emergency medicine decision support and risk education system (DS-RES) on the use of CT and MRI imaging. METHODS
system for the listed complaints ranged from 64.3% to 95.5%. Overall, physicians used DS-RES in 81.6% of encounters for these complaints. We designated the pre period as July 2008 to June 2009 and the post period as October 2009 through September 2010.
Emergency Medicine DS-RES
Statistical Analysis
DS-RES focuses on the diagnostic process in the ED with the goal of eliminating diagnostic delays and errors. It is based on a foundation of sound risk-reduction principles and includes point-of-care decision support tools in an integrated electronic health record (EHR), online riskreduction training, and regular feedback to physicians and nurses about their documentation performance using the EHR decision support tools (Figure 1). DS-RES templates for certain conditions include multiple alerts, key information (eg, identification of conditions as high risk, risk factors), documentation and flowsheet templates, order sets and order entry, trackboards to follow patient status and ordered/completed testing, and discharge documentation.
Data were available at three levels: encounter, chief complaint, and patient. Encounters during the pre and post periods included multiple visits from the same patients for one or more chief complaints. We examined imaging utilization at the level of encounters because each encounter represented an imaging opportunity. After excluding patients with a second or subsequent encounter for the same chief complaint, we adjusted encounters that occurred before and after DS-RES implementation for patient-level age, sex, and risk status. The latter was measured by DxCG score (Verisk Health,Inc.,Waltham, MA) and categorized into one of three risk groups: low (DxCG < 1), middle (DxCG $ 1 and < 5), and high (DxCG $ 5). We segmented the patient population with post-implementation encounters into these risk groups and divided the pre-implementation encounters into a similar risk distribution to adjust for these factors. We measured imaging utilization by physician orders and assessed the statistical significance of differences between the pre and post periods with the Z-test. We repeated this analysis after excluding encounters in which the chief complaints seemed least likely to require an order for imaging: fever in a child, laceration, and vaginal bleeding. We also assessed the proportion of 3- and 7-day rebound visits in the pre and post periods, similarly adjusting for age, sex, and risk status. Rebound was defined as a return visit to the ED or admission to an inpatient facility.
Design, Setting, and Population We conducted an age-, sex-, and risk-adjusted analysis of CT/MRI use and rebound rates before and after implementation of DS-RES. The medical center began using DS-RES in July 2009. Among patients who were not subsequently transferred to the hospital, we analyzed ED encounters for 10 chief complaints: abdominal pain, chest pain, fever in children, headache, head injury, laceration, lower and upper extremity injury, neck injury, shortness of breath, and vaginal bleeding. Provider use of DSRES was voluntary; excluding fever in children, the proportion of ED encounters in which physicians used the
Figure 1. Decision support and risk education system (DS-RES) screenshot. DS-RES provides documentation templates and point-of-care decision supports, as in this screenshot.
Impact of DS-RES on Imaging Use
55
Table 1. Distribution of All Encounters by Chief Complaint Chief Complaint
Pre DS-RES (n = 18,105)
Post DS-RES (n = 20,892)
Abdominal pain Chest pain Fever in a child Head injury Headache Laceration Lower extremity injury Neck injury Shortness of breath Upper extremity injury Vaginal bleeding
4879 3676 1153 589 1552 1492 342 346 2538 1061 477
5455 4522 1466 642 1686 1493 657 387 3025 1104 455
DS-RES = decision support and risk education system. Encounters include multiple patient visits for the same chief complaint.
RESULTS In the pre period, a total of 18,105 encounters occurred for patients with all chief complaints listed here; in the post period, 20,892 encounters occurred (Table 1). After excluding second or subsequent encounters for the same patient and chief complaint, a total of 12,531 encounters occurred in the pre period and 16,864 encounters occurred in the post period. The total number of unique patients across all chief complaints was 10,856 in the pre period and 14,834 in the post period (Table 2). The proportions of these patients in the low-, medium-, and high-risk groups were 11.4%, 24.8%, and 63.8%, respectively. In the pre period, the adjusted CT/MRI rate was 26.0%; in the post period, the comparable rate was 28.3% (p < 0.0001). Patterns of use shifted. Among enTable 2. Characteristics of Unique Patients With Encounters Related to All Chief Complaints
Male sex (%) Age (%) Younger than 20 y 21 44 y 45 64 y 65 y or older Race/ethnicity, % Non-Hispanic White Asian/Pacific Islander Black Latino Native American Other Unknown Risk status, DxCG score (%) 5
Pre DS-RES (n = 10,856)
Post DS-RES (n = 14,834)
43.6
43.4
16.2 27.7 33.0 23.1
17.2 27.5 32.0 23.4
75.4 4.9
77.2 4.6
4.6 4.4 1.1 2.6 6.9
5.3 5.7 0.8 1.9 4.5
10.7 27.9 61.4
8.6 25.1 66.3
DS-RES = decision support and risk education system.
counters in which patients were in the low-risk group, CT/MRI use decreased by 6.2% (95% confidence interval [CI] 4.0%–8.5%). Imaging use also decreased 3.3% (95% CI 1.6%–5.0%) in encounters involving medium-risk patients. However, in encounters with patients at high risk, the use of CT or MRI scans increased by 5.6% (95% CI 4.3%–7.0%). After excluding encounters related to fever in a child, laceration, and vaginal bleeding, CT/MRI use in encounters with low- and high-risk patients changed only minimally; use in encounters with medium-risk patients decreased by an additional 7 percentage points to 10.4% (95% CI 7.9%–12.8%). The proportion of patients with a 3-day rebound visit to either the ED or to an inpatient facility decreased between the pre and post periods by 1.4% (95% CI 0.7%–2.2%) from 9.7% to 8.3%. The proportion of patients with a 7-day rebound also decreased by 0.7% (95% CI 0.2% to 1.5%), from 13.9% to 13.2%. DISCUSSION Although imaging rates did not decrease after the implementation of an emergency medicine decision support and risk education system, patterns of use did shift to a statistically significant degree. A lower proportion of patients in the low- and medium-risk groups and a higher proportion of patients in the high-risk group had imaging tests after DS-RES implementation. In addition, 3- and 7day rebound rates decreased between the pre- and postimplementation periods. Strengths of our project include that it documents a shift in imaging utilization associated with risk groups, in addition to overall patterns of use. Potential explanations for the observed variation in use by risk include improved diagnostic processes resulting in less overuse of imaging among lower-risk patients and appropriately increased use among higher-risk patients. Another strength of our project is that, although we assessed a single ED, the population was relatively large. Our results are consistent with other reports of the difficulty of reducing overall imaging use in the ED (19,22). They also suggest that estimated potential reductions in imaging use by more than one third after implementation of clinical guidelines may be unduly optimistic (12). However, absolute decreases might not be an appropriate goal. Our findings suggest that our baseline imaging rates included both overuse among low- and medium-risk patients and underuse among high-risk patients. Depending on the proportion of each that is occurring in a given location or system, increasing the appropriateness of imaging utilization may have a variable effect on overall rates. However, additional research is needed to confirm the clinical impact of the shift in CT/MRI utilization we noted.
56
T. J. Carnevale et al.
Limitations One limitation of our quality-improvement project is the observational nature of our assessment. We controlled for potential confounders, such as age, sex, and disease burden, but other, unmeasured variables may have impacted our findings. We performed an aggregate mixed-model adjustment, which did not take into account any variations in the mix of chief complaints between the two periods; we assumed that chief complaints varied randomly during the two observation periods. We were also unable to directly measure diagnostic accuracy, an organizational goal of implementing DS-RES. The decrease in the 7-day rebound rate was not statistically significant. Decreased rebound rates suggest that fewer patients had unaddressed needs after an ED visit in the post period, which is likely to be a function, at least in part, of increased diagnostic accuracy. However, these data remain suggestive, and further study is required to understand the mechanisms underlying lower rebound rates and to identify any role played by increased diagnostic accuracy. CONCLUSIONS Implementation of an emergency medicine decision support and risk education initiative did not decrease overall CT/MRI rates in ED visits, but it was associated with a shift in utilization toward high-risk patients. We conclude that baseline imaging rates included components of both over- and underuse by risk group; concomitant decreases in rebound rates suggest greater diagnostic accuracy. REFERENCES 1. Korley FK, Pham JC, Kirsch TD. Use of advanced radiology during visits to US emergency departments for injury-related conditions, 1998-2007. JAMA 2010;304:1465–71. 2. Broder J, Warshauer DM. Increasing utilization of computed tomography in the adult emergency department, 2000-2005. Emerg Radiol 2006;13:25–30. 3. Larson DB, Johnson LW, Schnell BM, et al. National trends in CT use in the emergency department: 1995-2007. Radiology 2011;258: 164–73. 4. Prologo JD, Gilkeson RC, Diaz M, et al. CT pulmonary angiography: a comparative analysis of the utilization patterns in emergency department and hospitalized patients between 1998 and 2003. AJR Am J Roentgenol 2004;183:1093–6.
5. Raja AS, Mortele KJ, Hanson R, et al. Abdominal imaging utilization in the emergency department: trends over two decades. Int J Emerg Med 2011;4:19. 6. Boone JM, Brunberg JA. Computed tomography use in a tertiary care university hospital. J Am Coll Radiol 2008;5:132–8. 7. Friedman BW, Chilstrom M, Bijur PE, Gallagher EJ. Diagnostic testing and treatment of low back pain in United States emergency departments: a national perspective. Spine 2010;35:E1406–11. 8. Gilbert JW, Johnson KM, Larkin GL, Moore CL. Atraumatic headache in US emergency departments: recent trends in CT/MRI utilisation and factors associated with severe intracranial pathology. Emerg Med J 2012;29:576–81. 9. Pines JM, Mullins PM, Cooper JK, et al. National trends in emergency department use, care patterns, and quality of care of older adults in the United States. J Am Geriatr Soc 2013;61:12–7. 10. Freid VM, Bernstein AB. Health care utilization among adults aged 55-64 years: how has it changed over the past 10 years? NCHS Data Brief 2010;1–8. 11. Kirsch TD, Hsieh YH, Horana L, et al. Computed tomography scan utilization in emergency departments: a multi-state analysis. J Emerg Med 2011;41:302–9. 12. Melnick ER, Szlezak CM, Bentley SK, et al. CT overuse for mild traumatic brain injury. Jt Comm J Qual Patient Saf 2012;38:483–9. 13. Kocher KE, Meurer WJ, Desmond JS, Nallamothu BK. Effect of testing and treatment on emergency department length of stay using a national database. Acad Emerg Med 2012;19:525–34. 14. Broder J, Fordham LA, Warshauer DM. Increasing utilization of computed tomography in the pediatric emergency department, 2000-2006. Emerg Radiol 2007;14:227–32. 15. Pines JM. Trends in the rates of radiography use and important diagnoses in emergency department patients with abdominal pain. Med Care 2009;47:782–6. 16. Heller MT, Kanal E, Almusa O, et al. Utility of additional CT examinations driven by completion of a standard trauma imaging protocol in patients transferred for minor trauma. Emerg Radiol 2014;21: 341–7. 17. Shah KH, Slovis BH, Runde D, et al. Radiation exposure among patients with the highest CT scan utilization in the emergency department. Emerg Radiol 2013;20:485–91. 18. Kharbanda AB, Flood A, Blumberg K, Kreykes NS. Analysis of radiation exposure among pediatric trauma patients at national trauma centers. J Trauma Acute Care Surg 2013;74:907–11. 19. Levin DC, Rao VM, Parker L. The recent downturn in utilization of CT: the start of a new trend? J Am Coll Radiol 2012;9:795–8. 20. Blachar A, Tal S, Mandel A, et al. Preauthorization of CT and MRI examinations: assessment of a managed care preauthorization program based on the ACR appropriateness criteria and the Royal College of Radiology guidelines. J Am Coll Radiol 2006; 3:851–9. 21. Stiell IG, Clement CM, Grimshaw J, et al. Implementation of the Canadian C-spine rule: prospective 12 centre cluster randomised trial. BMJ 2009;339:b4146. 22. Stiell IG, Clement CM, Grimshaw JM, et al. A prospective clusterrandomized trial to implement the Canadian CT head rule in emergency departments. CMAJ 2010;182:1527–32. 23. Bailey JE, Wan JY, Mabry LM, et al. Does health information exchange reduce unnecessary neuroimaging and improve quality of headache care in the emergency department? J Gen Intern Med 2013;28:176–83.
Impact of DS-RES on Imaging Use
ARTICLE SUMMARY 1. Why is this topic important? Increased use of computed tomography (CT) and magnetic resonance imaging (MRI) in the emergency department is well documented. The emergency department is the only setting in which the use of CT in the Medicare population failed to decrease between 2000 and 2010. 2. What does this study attempt to show? We assess the impact of an emergency medicine risk decision support and risk education system that included comprehensive point-of-care decision support on CT/ MRI use. 3. What are the key findings? Overall imaging rates increased. However, CT/MRI rates decreased among low- and medium-risk patients and increased among high-risk patients. 4. How is patient care impacted? High rates of CT and MRI use may reflect elements of underuse among high-risk patients and overuse among low- and medium-risk patients.
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