Inflamm Bowel Dis Volume 21, Number 8, August 2015
Letters to the Editor
highlights several points in our article that would benefit from additional discussion. Analytic morphomics provides a semiautomated method of quantifying tissue composition using computed tomography. We hypothesized that this technology may provide a means to objectively characterize the clinical gestalt of postoperative complication risk in patients undergoing bowel resection for Crohn’s disease. We agree that data on wound classification and C-reactive protein are important covariates that may adjust the impact of fat composition on postoperative wound infection. We considered these points in our analysis; however, as a function of the retrospective study design, wound characteristics were not uniformly described. Furthermore, C-reactive protein values were only available in 187 of 274 subjects within a 6week window of their surgery; we elected not to use imputation for missing data given the wide range of C-reactive protein values. We also agree that cumulative steroid exposure, accounting for both dose and duration, is likely an important covariate in assessing surgical outcomes. Extracting detailed data on prednisone exposure from a retrospective chart review is unreliable and best suited for future prospective work. Data detailing surgical history would be additive to this analysis and we plan to include these data in future prospective studies. We elected to present fat distribution as a subcutaneousto-visceral standardized ratio. Projecting the data as visceral-to-subcutaneous fat ratios has a collinear relationship to the outcome. Finally, we considered the role of gender on fat distribution. Female fat distribution is skewed towards a greater proportion of visceral fat compared with males. When stratifying by gender, subcutaneous-to-visceral fat ratios are greater in males with complications (1.18, SD 1.09) compared with females (0.84, SD 0.41). In those without complications, male fat ratios (0.73, SD 0.61) were also greater than females (0.59, SD 0.41). However, in our multivariate adjusted model for complications incorporating fat distribution, gender was not significant (odds ratio 1.51, 95% confidence interval, 0.76– 3.01), likely because the relative changes in fat distribution were similar between
E20
genders. We agree that when considering fat distribution as a univariate predictor, value ranges associated with complication differ by gender. Evaluating the prognostic capabilities of fat distribution in inflammatory bowel disease will be an element of our future work using analytic morphomics. Building from this proof-of-concept study, future prospective study designs investigating fat distribution will better account for the limitations noted.
Ryan W. Stidham, MD* Akbar K. Waljee, MD, MS*,† Nicholas M. Day, MD‡ Carrie L. Bergmans, BS* Katelin M. Zahn, BS‡ Peter D. R. Higgins, MD, PhD, MSc* Stewart C. Wang, MD, PhD§ Grace L. Su, MD*,† *Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan † Center for Clinical Management Research, VA Ann Arbor Health Services Research & Development, Ann Arbor, Michigan ‡ Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan § Department of Surgery, University of Michigan Health System, Ann Arbor, Michigan
Use of CT Scan in Ulcerative Colitis Patients Presenting to the Emergency Department To the Editor: I have recently read the article by Gashin et al.1 This was a very helpful and interesting study and brought up a very The author has no conflicts of interest to disclose. Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. DOI 10.1097/MIB.0000000000000505 Published online 2 July 2015.
pertinent issue, most commonly faced in the emergency department, i.e., whether or not computed tomography (CT) will be beneficial in the management of a patient with ulcerative colitis. Avoiding unnecessary CT scans in this patient population is of crucial value, not only just from a cost-effective standpoint but also to avoid unnecessary radiation exposure. I do believe that there are certain issues with this study that need to be addressed and should be taken under consideration while interpreting the results of this study. First, this study does not describe the patients’ disease severity at baseline. A patient who has mild/well-controlled disease will require less aggressive workup as compared with a patient with severe/ uncontrolled disease. About half of the patient population was not on any medications for ulcerative colitis at the time of presentation. This could be due to mild/ well-controlled disease, which in this case can skew the results of the study by involving patients who were not very sick and probably would not have benefited from a CT scan in the first place. This was also suggested by other data such as relatively normal white blood cell count and hemoglobin values.2 Moreover, less than 10% of the patients had erythrocyte sedimentation rate or C-reactive protein checked at the time of presentation, both of which are of utmost importance in these patients.3 Second, the study does not address the follow-up of these patients. As we know, CT scans can easily miss certain complications of ulcerative colitis such as microperforations and ulcerative colon cancer. Such complications require a colonoscopy. Moreover, patients with history of ulcerative colitis presenting with a significant rectal bleed (one-third of the patients in this study) and normal CT scan require a colonoscopy to rule out complications that can be missed by CT scans. This study considered CT scans as the final diagnostic test in these patients, which is not true in real life. Finally, one-third of the patient population had a history of colectomy. As we know that ulcerative colitis is primarily a disease of the colon, a history of colectomy reduces the patients’ risk of developing a complication secondary to ulcerative colitis later in life. This aspect of the study also adds
| www.ibdjournal.org
Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. Unauthorized reproduction of this article is prohibited.
Inflamm Bowel Dis Volume 21, Number 8, August 2015
to skewing of the results by selecting a patient population that has low risk of ulcerative colitis–related complications to begin with.
Shahzaib Nabi, MD Department of Internal Medicine, Henry Ford Health System, Detroit, Michigan
REFERENCES 1. Gashin L, Villafuerte-Galvez J, Leffler DA, et al. Utility of CT in the emergency department in patients with ulcerative colitis. Inflamm Bowel Dis. 2015;21:793–800. 2. Koutroubakis IE, Ramos-Rivers C, Regueiro M, et al. Persistent or recurrent anemia is associated with severe and disabling inflammatory bowel disease. Clin Gastroenterol Hepatol. [published online ahead of print April 8, 2015]. doi: 10.1016/j.cgh.2015.03.029. 3. Henriksen M, Jahnsen J, Lygren I, et al. C-reactive protein: a predictive factor and marker of inflammation in inflammatory bowel disease. Results from a prospective population-based study. Gut. 2008;57:1518–1523.
Reply to Use of CT Scan in Ulcerative Colitis Patients Presenting to the Emergency Department Reply: We would like to thank Dr. Nabi for his interest in our recently published article,1 which proposed a model to identify patients with ulcerative colitis (UC) in the emergency department (ED) who may benefit from a computed tomography (CT) scan. We agree with Dr. Nabi that CT scans are important in the diagnostic evaluation and management of patients with inflammatory bowel disease, but their overuse can be detrimental to both the patient (radiation expose, nephrotoxicity) and the health care system (excess cost). Attempting to refine who best needs these scans is crucial. We would like to take this opportunity to address some of Dr. Nabi’s comments. Although we do not describe the disease severity of the patients at baseline and this is a limitation of our retrospective review, all of the patients were evaluated in The authors have no conflict of interest to disclose. Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. DOI 10.1097/MIB.0000000000000513 Published online 2 July 2015.
the ED and underwent a CT scan. Therefore, one would expect that these patients had significant-enough symptoms to prompt an ED evaluation and imaging. Even patients with previously well-controlled disease can present at any time point with severe symptoms regardless of which medications they are on or supposed to be on. In fact, the reason for an ED visit is often an acute flare of symptoms. Although only half of the patients were on medications at presentation, this may be due to a lack of recent symptoms or nonadherence to medications, the latter of which is associated with an increased risk of flares.2,3 Although relatively normal white blood cell count and hematocrit may suggest less inflammation or bleeding, they are not the best predictors of disease severity. C-reactive protein and fecal calprotectin have been shown to more accurately predict endoscopic inflammation.4,5 Moreover, hemoglobin levels may be falsely elevated in dehydrated patients with flares. We do agree that C-reactive protein is helpful in the evaluation of patients with UC, but unfortunately, this is not standard of care in our ED and often does not occur until the patients reach the floor. Therefore, the results of these tests do not always influence the decision to obtain a CT scan in the ED. To address Dr. Nabi’s second point, we agree that the study does not address the follow-up of these patients. However, the main objective of our study was to focus on the ED visit and the frequency of clinically significant CT findings in patients with UC in the ED. We showed that 63% of CT scans did not have clinically significant findings. Using our model, patients presenting with bloody diarrhea and found to have a score of 4 or higher may not require a CT. In these patients, an abdominal x-ray as proposed in the algorithm by Pola et al6 may be more appropriate. Although CT scans may miss certain complications including microperforations and colon cancer, the role of the CT is not to detect colon cancer. We do agree with Dr. Nabi that eventual endoscopic assessment is often essential in the evaluation of a patient presenting to the ED with UC to assess the severity of disease, help with risk prognostication, and rule out CMV. By no means, are we suggesting CT scans are the
Letters to the Editor
final diagnostic test. In fact, our point is that not all patients require CT scans. Finally, Dr. Nabi comments on the fact that one-third of our patients had a history of colectomy, which skewed the results by selecting a patient population with low risk of UC-related complications. Although in our study, the rate of UCrelated complications was quite rare (n ¼ 3) and none of these patients had colectomy, the aim of our study was to identify any clinically significant finding not just those that were UC related. In a subgroup analysis, we found that patients with colectomy were more likely to have clinically significant findings on CT scan than those without colectomy (30/53 [56.6%] versus 30/110 [27.3%]). Therefore, the inclusion of the colectomy group actually increased the proportion of CTs with clinically significant findings rather than decreased it. Overall, this supports that (1) there are few UCrelated complications identified on CT and (2) patients presenting with typical UC symptoms of bloody diarrhea in the absence of nausea and recent surgery are less likely to have positive CT findings as depicted by our model.
Laurie Gashin, MD Adam S. Cheifetz, MD Department of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
REFERENCES 1. Gashin L, Villafuerte-Galvez J, Leffler DA, et al. Utility of CT in the emergency Department in patients with ulcerative colitis. Inflamm Bowel Dis. 2015;21:793–800. 2. Higgins PD, Rubin DT, Kaulback K, et al. Systematic review: impact of non-adherence to 5-aminosalicylic acid products on ulcerative colitis flares. Aliment Pharmacol Ther. 2009;29:247–257. 3. Feagins LA, Igbal R, Spechler SJ. Case-control study of factors that trigger inflammatory bowel disease flares. World J Gastroenterol. 2014;20:4329–4334. 4. Schoepfer AM, Beglinger C, Straumann A, et al. Fecal calprotectin more accurately reflects endoscopic activity of ulcerative colitis than the Lichtiger Index, C-reactive protein, platelets, hemoglobin, and blood leukocytes. Inflamm Bowel Dis. 2013;19:332–341. 5. Langhorst J, Elsenbruch S, Koelzer J, et al. Noninvasive markers in the assessment of intestinal inflammation in inflammatory bowel diseases: performance of fecal lactoferrin, calprotectin, and PMN-elastase, CRP, and clinical indices. Am J Gastroenterol. 2008;103:162–169. 6. Pola S, Patel D, Ramamoorthy S, et al. Strategies for the care of adults hospitalized for active ulcerative colitis. Clin Gastroenterol Hepatol. 2012;10:1315–1325.
www.ibdjournal.org |
Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. Unauthorized reproduction of this article is prohibited.
E21
Letters to the Editor
highlights several points in our article that would benefit from additional discussion. Analytic morphomics provides a semiautomated method of quantifying tissue composition using computed tomography. We hypothesized that this technology may provide a means to objectively characterize the clinical gestalt of postoperative complication risk in patients undergoing bowel resection for Crohn’s disease. We agree that data on wound classification and C-reactive protein are important covariates that may adjust the impact of fat composition on postoperative wound infection. We considered these points in our analysis; however, as a function of the retrospective study design, wound characteristics were not uniformly described. Furthermore, C-reactive protein values were only available in 187 of 274 subjects within a 6week window of their surgery; we elected not to use imputation for missing data given the wide range of C-reactive protein values. We also agree that cumulative steroid exposure, accounting for both dose and duration, is likely an important covariate in assessing surgical outcomes. Extracting detailed data on prednisone exposure from a retrospective chart review is unreliable and best suited for future prospective work. Data detailing surgical history would be additive to this analysis and we plan to include these data in future prospective studies. We elected to present fat distribution as a subcutaneousto-visceral standardized ratio. Projecting the data as visceral-to-subcutaneous fat ratios has a collinear relationship to the outcome. Finally, we considered the role of gender on fat distribution. Female fat distribution is skewed towards a greater proportion of visceral fat compared with males. When stratifying by gender, subcutaneous-to-visceral fat ratios are greater in males with complications (1.18, SD 1.09) compared with females (0.84, SD 0.41). In those without complications, male fat ratios (0.73, SD 0.61) were also greater than females (0.59, SD 0.41). However, in our multivariate adjusted model for complications incorporating fat distribution, gender was not significant (odds ratio 1.51, 95% confidence interval, 0.76– 3.01), likely because the relative changes in fat distribution were similar between
E20
genders. We agree that when considering fat distribution as a univariate predictor, value ranges associated with complication differ by gender. Evaluating the prognostic capabilities of fat distribution in inflammatory bowel disease will be an element of our future work using analytic morphomics. Building from this proof-of-concept study, future prospective study designs investigating fat distribution will better account for the limitations noted.
Ryan W. Stidham, MD* Akbar K. Waljee, MD, MS*,† Nicholas M. Day, MD‡ Carrie L. Bergmans, BS* Katelin M. Zahn, BS‡ Peter D. R. Higgins, MD, PhD, MSc* Stewart C. Wang, MD, PhD§ Grace L. Su, MD*,† *Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan † Center for Clinical Management Research, VA Ann Arbor Health Services Research & Development, Ann Arbor, Michigan ‡ Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan § Department of Surgery, University of Michigan Health System, Ann Arbor, Michigan
Use of CT Scan in Ulcerative Colitis Patients Presenting to the Emergency Department To the Editor: I have recently read the article by Gashin et al.1 This was a very helpful and interesting study and brought up a very The author has no conflicts of interest to disclose. Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. DOI 10.1097/MIB.0000000000000505 Published online 2 July 2015.
pertinent issue, most commonly faced in the emergency department, i.e., whether or not computed tomography (CT) will be beneficial in the management of a patient with ulcerative colitis. Avoiding unnecessary CT scans in this patient population is of crucial value, not only just from a cost-effective standpoint but also to avoid unnecessary radiation exposure. I do believe that there are certain issues with this study that need to be addressed and should be taken under consideration while interpreting the results of this study. First, this study does not describe the patients’ disease severity at baseline. A patient who has mild/well-controlled disease will require less aggressive workup as compared with a patient with severe/ uncontrolled disease. About half of the patient population was not on any medications for ulcerative colitis at the time of presentation. This could be due to mild/ well-controlled disease, which in this case can skew the results of the study by involving patients who were not very sick and probably would not have benefited from a CT scan in the first place. This was also suggested by other data such as relatively normal white blood cell count and hemoglobin values.2 Moreover, less than 10% of the patients had erythrocyte sedimentation rate or C-reactive protein checked at the time of presentation, both of which are of utmost importance in these patients.3 Second, the study does not address the follow-up of these patients. As we know, CT scans can easily miss certain complications of ulcerative colitis such as microperforations and ulcerative colon cancer. Such complications require a colonoscopy. Moreover, patients with history of ulcerative colitis presenting with a significant rectal bleed (one-third of the patients in this study) and normal CT scan require a colonoscopy to rule out complications that can be missed by CT scans. This study considered CT scans as the final diagnostic test in these patients, which is not true in real life. Finally, one-third of the patient population had a history of colectomy. As we know that ulcerative colitis is primarily a disease of the colon, a history of colectomy reduces the patients’ risk of developing a complication secondary to ulcerative colitis later in life. This aspect of the study also adds
| www.ibdjournal.org
Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. Unauthorized reproduction of this article is prohibited.
Inflamm Bowel Dis Volume 21, Number 8, August 2015
to skewing of the results by selecting a patient population that has low risk of ulcerative colitis–related complications to begin with.
Shahzaib Nabi, MD Department of Internal Medicine, Henry Ford Health System, Detroit, Michigan
REFERENCES 1. Gashin L, Villafuerte-Galvez J, Leffler DA, et al. Utility of CT in the emergency department in patients with ulcerative colitis. Inflamm Bowel Dis. 2015;21:793–800. 2. Koutroubakis IE, Ramos-Rivers C, Regueiro M, et al. Persistent or recurrent anemia is associated with severe and disabling inflammatory bowel disease. Clin Gastroenterol Hepatol. [published online ahead of print April 8, 2015]. doi: 10.1016/j.cgh.2015.03.029. 3. Henriksen M, Jahnsen J, Lygren I, et al. C-reactive protein: a predictive factor and marker of inflammation in inflammatory bowel disease. Results from a prospective population-based study. Gut. 2008;57:1518–1523.
Reply to Use of CT Scan in Ulcerative Colitis Patients Presenting to the Emergency Department Reply: We would like to thank Dr. Nabi for his interest in our recently published article,1 which proposed a model to identify patients with ulcerative colitis (UC) in the emergency department (ED) who may benefit from a computed tomography (CT) scan. We agree with Dr. Nabi that CT scans are important in the diagnostic evaluation and management of patients with inflammatory bowel disease, but their overuse can be detrimental to both the patient (radiation expose, nephrotoxicity) and the health care system (excess cost). Attempting to refine who best needs these scans is crucial. We would like to take this opportunity to address some of Dr. Nabi’s comments. Although we do not describe the disease severity of the patients at baseline and this is a limitation of our retrospective review, all of the patients were evaluated in The authors have no conflict of interest to disclose. Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. DOI 10.1097/MIB.0000000000000513 Published online 2 July 2015.
the ED and underwent a CT scan. Therefore, one would expect that these patients had significant-enough symptoms to prompt an ED evaluation and imaging. Even patients with previously well-controlled disease can present at any time point with severe symptoms regardless of which medications they are on or supposed to be on. In fact, the reason for an ED visit is often an acute flare of symptoms. Although only half of the patients were on medications at presentation, this may be due to a lack of recent symptoms or nonadherence to medications, the latter of which is associated with an increased risk of flares.2,3 Although relatively normal white blood cell count and hematocrit may suggest less inflammation or bleeding, they are not the best predictors of disease severity. C-reactive protein and fecal calprotectin have been shown to more accurately predict endoscopic inflammation.4,5 Moreover, hemoglobin levels may be falsely elevated in dehydrated patients with flares. We do agree that C-reactive protein is helpful in the evaluation of patients with UC, but unfortunately, this is not standard of care in our ED and often does not occur until the patients reach the floor. Therefore, the results of these tests do not always influence the decision to obtain a CT scan in the ED. To address Dr. Nabi’s second point, we agree that the study does not address the follow-up of these patients. However, the main objective of our study was to focus on the ED visit and the frequency of clinically significant CT findings in patients with UC in the ED. We showed that 63% of CT scans did not have clinically significant findings. Using our model, patients presenting with bloody diarrhea and found to have a score of 4 or higher may not require a CT. In these patients, an abdominal x-ray as proposed in the algorithm by Pola et al6 may be more appropriate. Although CT scans may miss certain complications including microperforations and colon cancer, the role of the CT is not to detect colon cancer. We do agree with Dr. Nabi that eventual endoscopic assessment is often essential in the evaluation of a patient presenting to the ED with UC to assess the severity of disease, help with risk prognostication, and rule out CMV. By no means, are we suggesting CT scans are the
Letters to the Editor
final diagnostic test. In fact, our point is that not all patients require CT scans. Finally, Dr. Nabi comments on the fact that one-third of our patients had a history of colectomy, which skewed the results by selecting a patient population with low risk of UC-related complications. Although in our study, the rate of UCrelated complications was quite rare (n ¼ 3) and none of these patients had colectomy, the aim of our study was to identify any clinically significant finding not just those that were UC related. In a subgroup analysis, we found that patients with colectomy were more likely to have clinically significant findings on CT scan than those without colectomy (30/53 [56.6%] versus 30/110 [27.3%]). Therefore, the inclusion of the colectomy group actually increased the proportion of CTs with clinically significant findings rather than decreased it. Overall, this supports that (1) there are few UCrelated complications identified on CT and (2) patients presenting with typical UC symptoms of bloody diarrhea in the absence of nausea and recent surgery are less likely to have positive CT findings as depicted by our model.
Laurie Gashin, MD Adam S. Cheifetz, MD Department of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
REFERENCES 1. Gashin L, Villafuerte-Galvez J, Leffler DA, et al. Utility of CT in the emergency Department in patients with ulcerative colitis. Inflamm Bowel Dis. 2015;21:793–800. 2. Higgins PD, Rubin DT, Kaulback K, et al. Systematic review: impact of non-adherence to 5-aminosalicylic acid products on ulcerative colitis flares. Aliment Pharmacol Ther. 2009;29:247–257. 3. Feagins LA, Igbal R, Spechler SJ. Case-control study of factors that trigger inflammatory bowel disease flares. World J Gastroenterol. 2014;20:4329–4334. 4. Schoepfer AM, Beglinger C, Straumann A, et al. Fecal calprotectin more accurately reflects endoscopic activity of ulcerative colitis than the Lichtiger Index, C-reactive protein, platelets, hemoglobin, and blood leukocytes. Inflamm Bowel Dis. 2013;19:332–341. 5. Langhorst J, Elsenbruch S, Koelzer J, et al. Noninvasive markers in the assessment of intestinal inflammation in inflammatory bowel diseases: performance of fecal lactoferrin, calprotectin, and PMN-elastase, CRP, and clinical indices. Am J Gastroenterol. 2008;103:162–169. 6. Pola S, Patel D, Ramamoorthy S, et al. Strategies for the care of adults hospitalized for active ulcerative colitis. Clin Gastroenterol Hepatol. 2012;10:1315–1325.
www.ibdjournal.org |
Copyright © 2015 Crohn’s & Colitis Foundation of America, Inc. Unauthorized reproduction of this article is prohibited.
E21
