Emergency department diagnosis and management of constipation in the United States, 2006-2017

a b s t r a c t

Background: Constipation is a common diagnosis in adults and children. Emergency department (ED) visits for constipation increased from 1980 to 2010. Since then, efforts have aimed to reduce resource utilization for con- stipation in the ED setting. Our objective is to examine contemporary ED practice patterns in the context of up- dated care guidelines.

Methods: We conducted a cross-sectional study using the National Hospital Ambulatory Medical Care Survey from 2006 to 2017. Encounters with a constipation diagnosis were included. We examined rates of ED visits, di- agnostic testing, and medication use. We also compared general and pediatric ED practice patterns for children. Results: Approximately 1.3 million ED visits with a diagnosis of constipation occurred annually, with pediatric en- counters comprising one-third of all visits. There was a 114% increase in ED visits for constipation over the study period. Urinalysis and imaging increased by 17% and 15%, respectively. Older patients were more likely to un- dergo diagnostic testing. No significant changes in laboratory testing, radiographs, or osmotic laxative prescrip- tions were observed among children. Compared to pediatric EDs, general EDs were more likely to perform CBC (29% vs. 15%) and urinalysis testing (42% vs 31%). General EDs were less likely to prescribe osmotic laxatives for children compared to pediatric EDs (26% vs. 37%).

Conclusion: ED visits for constipation have increased significantly since 2006. Rates of Diagnostic tests.and pre- scriptions have not changed despite published evidence and guidelines that the diagnosis of constipation does not require imaging, and that the management of constipation requires consistent outpatient treatment. Oppor- tunities exist to reduce ED resource utilization through knowledge dissemination and implementation.

(C) 2022

  1. Introduction

Constipation is a common emergency department (ED) diagnosis [1] that carries significant burden and Healthcare costs [2]. Nationally- representative studies found an increase in constipation-related visits in both the outpatient [3] and ED settings [4] in the United States from 1993 to 2011, with the most significant increase in children. Radiographs are obtained in up to 66% of children in the ED with constipation [5,6].

Updated guidelines have emphasized that constipation requires consistent outpatient management with dietary changes and polyethyl- ene glycol [7-9]. The guidelines [7-9] also recommend against routine blood tests and radiographs, as functional constipation is a clinical diag- nosis [7,10,11] based on ROME IV criteria for both adults and children

* Corresponding author at: Division of Pediatric Emergency Medicine, Department of Pediatrics, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, United States of America.

E-mail address: [email protected] (A.Z. Zhou).

[12-14]. It is unknown whether these guidelines have changed ED visits and management of constipation in the last decade. Although studies have examined pediatric constipation-related ED visits [5] and hospital- izations [15], they were confined to free-standing children’s hospitals. Thus, these may not be broadly representative, as 80-90% of children are evaluated in general EDs [16,17].

Recently, several institutions have made efforts to reduce radiograph use for Suspected constipation [18-21]. There have also been outpatient institutional efforts to reduce the rate of ED visits for constipation [20,22]. It is unclear if these efforts are widespread across the U.S.

Our objective is to evaluate contemporary ED practice patterns across the U.S. in the diagnosis and treatment of constipation, with a focus on pediatric encounters. Given published guidelines emphasizing outpatient management and minimal testing [7-9], we hypothesize that there has been a Decrease in ED visits, laboratory tests and imaging. We sought to identify trends in the rates of ED visits, diagnostic testing, and management. Knowledge of recent practice patterns and guideline

0735-6757/(C) 2022

uptake will identify key opportunities to optimize constipation manage- ment in the ED setting.

  1. Methods
    1. Data source

We conducted a cross-sectional study using the National Hospital Ambulatory Medical Care Survey [23]. This national probabil- ity sample survey includes visits to hospital EDs with deidentified patient information. It uses a multistage probability sample design to ensure nationally Representative samples [24]. The National Center for Health Statistics Ethics Review Board approves of research using NHAMCS [25]. The Ann and Robert H. Lurie Children’s Hospital Institutional Review Board exempted this work as non-human subjects research.

    1. Study design

We included ED visits with a constipation diagnosis in any of the three (2006-2014) or five (2014-2017) diagnosis fields. We defined constipation based on prior literature [3,5,15] using ICD-9 and ICD-10 codes (Supplementary Table 1). We excluded visits that were a result of injury, overdose, or a side effect of prior medical or surgical treat- ments. We also excluded visits if gastrointestinal comorbidities, such as Gastrostomy tube or short gut syndrome, were concomitant diagno- ses (Supplementary Table 1). The start year of 2006 was chosen to coin- cide with the implementation of the Multum Lexicon Plus drug classification system to ensure uniform drug coding. Survey data was available through 2017 at the time of analysis.

    1. Data abstraction

Variables of interest were harmonized across the years in SAS Enter- prise Guide (Version, SAS Institute Inc., Cary, NC) [26]. Demographics included age, sex, race, and geographic region. Age was categorized as 0-18 years, 19-40 years, 41-60 years, and >60 years. Pe- diatric EDs were defined as those where at least 75% of patients were

<=18 years old, consistent with prior work [27-29]. We defined teaching

hospitals as those where >=10% of ED visits involved a resident/intern provider [28,30] or if the hospital has an emergency medicine residency program. Diagnostic tests included complete blood count , elec- trolytes, urinalysis (UA), any imaging, radiograph (X-ray), ultrasound, and computed tomography (CT). Electrolyte is a composite of the sur- vey fields BMP (basic metabolic panel), CMP (comprehensive metabolic panel) and Electrolyte; BMP and CMP were available starting 2015. The survey field of radiograph does not specify the body part imaged. The CT survey field specified abdomen/pelvis starting 2012. Since our study pe- riod starts in 2006, we omitted the body part specification and labeled an encounter as involving a CT scan if the “CT scan” field is coded as “yes,” regardless of which body part(s) were imaged.

We categorized medications into 5 therapeutic classes (bulking agents, stool softener, stimulant laxatives, osmotic laxatives, and sup- pository/enema), consistent with prior studies [8,31] (Supplementary Table 2). We abstracted their generic components using Multum Lexi- con Plus. Combination drugs were classified under all applicable classes.

    1. Data analysis

Analyses were performed in the open-source R software environ- ment [32] with the add-on package “survey” [33] to implement proce- dures for generating estimates and standard errors for the complex multistage probability sampling scheme. We calculated survey- weighted estimates of counts and proportions along with associated standard errors. We grouped data into 3-year intervals to reduce unre- liable estimates, defined as any estimate based on fewer than 30 un- weighted visits or for which the calculated standard error was over

30%. To compare groups defined by age or year interval, we conducted weighted chi-square tests with Rao-Scott second order correction [34]. We evaluated trends over time using weighted logistic regression with year interval as the sole covariate. We did not run tests or fit models if any estimates were unreliable. The significance level for all inferences was 0.05.

  1. Results
    1. Constipation visits

There was an average of 1,330,000 (SE 75,000) ED encounters annu- ally with a diagnosis of constipation from 2006 to 2017; 37% were by children (<=18 years old) (Table 1). Most children were evaluated in general EDs, representing approximately 78% of pediatric visits for constipation. Most patients were female and of white race, and more patients presented in the south than other regions (Table 1). The ab- solute number and proportion of ED visits (Fig. 1) with a diagnosis of constipation significantly increased over the study period for adults and children (p < 0.001 for each group), with an overall 114% increase in constipation-related visits during the study period. When stratified by age, there was a 128% increase for children and 105% increase for adults.

    1. Diagnostic testing

The most commonly obtained laboratory tests were CBC and urinal- ysis; these tests were obtained during almost half of all ED visits for con- stipation (Table 2). Laboratory testing was used more frequently in the ED for adults compared with children (Table 3). There was no signifi- cant change over time in CBC testing, while electrolyte and urinalysis use increased (Table 3).

Diagnostic imaging was performed during 66% of ED visits for consti- pation. imaging use, particularly CT imaging, was significantly higher in adults compared to children (Table 3). Over the study period, there was an increase in overall imaging use, but the rate of individual imaging modalities stayed constant (Table 3).

Table 1

Emergency department patient demographics, 2006-2017.

Characteristics Average annual constipation visits (in thousands) N (SE) Total 1330 (75)

Age, years

0-18 490 (34)

19-40 280 (25)

41-60 220 (18)

>60 340 (23)


Female 770 (46)

Male 560 (37)


White 730 (46)

African American 330 (30)

Hispanic 250 (22)

Other 31 (4.6)


Northeast 198 (15)

Midwest 300 (33)

South 556 (58)

West 280 (32)

Type of ED

General 1230 (70)

Pediatric 110 (19)

Teaching Hospital Status

Non-teaching 995 (62)

Teaching 340 (32)

Fig. 1. Average annual number (panel A) and percent of ED visits (panel B) with a diagnosis of constipation.

Panel A







2006-2007 2008-2009

2010-2011 2012-2013


2014-2015 2016-2017

All patients Adult patients Pediatric patients

Panel B







2006-2007 2008-2009 2010-2011 2012-2013 2014-2015 2016-2017


All patients Adult patients Pediatric patients

When comparing diagnostic tests for children in general EDs and pediatric EDs, general EDs were more likely to perform laboratory tests and imaging than pediatric EDs (Table 4). General EDs de- monstrated no significant change in CBC (p = 0.96) or UA use (p = 0.14) in children over time. There was, however, an increase in overall imaging use (p = 0.01) from 53% (SE 4.4%) in 2006-2008 to 66% (SE 4.7%) in 2015-2017. There was a concomitant increase in X-ray use (p = 0.02) from 44% (SE 11%) to 60% (SE 5%) in children treated in general EDs with constipation. In contrast, pediatric EDs experienced no change in the rate of overall imaging (p = 0.28) or X-ray use (p = 0.11). Reliable estimates could not be obtained for other categories of diagnostic tests.

Percent of ED visits, %

Number of constipation visits, in thousands

    1. Management

The most commonly prescribed medications in the ED for constipa- tion were osmotic laxatives, followed by enemas or suppositories

(Table 2). Other agents such as stool softeners, stimulant laxatives, and bulking agents were uncommonly used.

Children were more likely than adults to receive osmotic laxatives in the ED (Table 3). General EDs were less likely to treat children with os- motic laxatives than pediatric EDs (Table 4). However, there was an in- crease in osmotic laxative prescriptions for children in general EDs over the study period (p = 0.04) from 15% (SE 3.9%) in 2006-2008 to 29% (SE 4.9%) in 2015-2017. No generalizable estimates can be made for other drug classes because their use was rare.

  1. Discussion

In this nationally representative, cross-sectional study of ED encoun- ters, we found a significant increase in the number of ED visits for con- stipation from 2006 to 2017. These increases are greater than the concomitant rise in the U.S. population (8.9%) during the study period [35]. There was not only an increase in the number of ED visits, but

Table 2 Overall rates of emergency department diagnostic tests and management for constipation, 2006-2017.

Table 4

Emergency department diagnostic tests and management of constipation for children by site of care, 2006-2017. Overall rate represents the rate for all visits in children regardless of General or Pediatric EDs.

Emergency department % of visits (SE)

Laboratory Testing

CBC 47 (1.6)

Urinalysis 45 (1.6)


Laboratory testing


13 (1.5)

15 (1.8)

6.6 (2.0)


26 (2.1)

29 (2.4)

15 (3.1)



39 (2.3)

42 (2.6)

31 (3.5)


Overall % of visits (SE)

General ED % of visits (SE)

Pediatric ED % of visits (SE)



Any imaging

66 (1.3)


47 (1.3)


5.2 (0.6)


20 (1.1)

Any imaging

58 (2.2)

61 (2.2)

49 (4.7)



0.55 (0.15)


48 (2.3)

50 (2.5)

41 (4.4)



Osmotic laxative 20 (1.3)

Stimulant laxative 0.3 (0.11)

Stool softener 0.9 (0.21)

Bulking agents 0.1 (0.1)

Enema/suppository 3.1 (0.4) CBC, complete blood count; CT, computed tomography; MRI, magnetic resonance imaging.

Ultrasound 5.2 (1.1) 4.4 (1.0) 8.2 (3.0) –

CT scan 9.2 (1.5) 10 (1.8) 5.9 (2.0) –

Treatment – in ED or on discharge

Osmotic Laxative 28 (2.3) 26 (2.6) 37 (4.3) 0.011

* P-values from chi-square tests of whether pediatric EDs differ from general EDs. If an estimate is unreliable, the corresponding row is marked “-” for not applicable.

also in the proportion of ED visits with a constipation diagnosis for all age groups.

A prior study found a 42% increase in constipation-related ED visits in the US from 2006 to 2011 [4]. In this more contemporary study since the publication of new evidence and guidelines, we found a 114% increase in constipation-related ED visits from 2006 to 2017. The reasons behind the increase in ED visits are likely multifactorial. The in- creased rate may reflect rising symptomatic complaints, amplified pa- tient awareness, desire for timely treatment, or increased physician attentiveness to Diagnostic coding. Regardless of the etiologies, our find- ings highlight opportunities to reduce the high ED utilization rate. One study found 45% of children with constipation-related ED encounters did not pursue an outpatient visit in the preceding or subsequent 30 days [1]. Another found 41% of children hospitalized for constipation did not have a previous outpatient visit for the same diagnosis [36]. Re- cently, single-center studies have focused on improving outpatient follow-up and decreasing ED utilization [20,22]. These studies charac- terized structured outpatient programs for patients with chronic functional constipation that led to decreases in ED visits, hospital admis- sions, and healthcare costs. Our findings suggest that such institutional efforts, while effective, have not been widely implemented.

Diagnostic tests were frequently performed during ED encounters for constipation although current guidelines do not recommend their routine use [7,10,11]. Diagnostic tests are indicated only in cases that are ambiguous or concerning for serious pathology [5,10,18]. Consistent with prior findings, we found that older patients were more likely to undergo diagnostic studies [37].

We found that 48% of children with constipation underwent radio- graphs in the ED, consistent with prior reported rates (28-66%) [5,6]. There has been no large-scale change in the use of radiographs over the study period in pediatric EDs. This represents profound opportuni- ties for improvement as several pediatric EDs have successfully reduced radiograph use for suspected constipation by 50% or more without con- comitant increase in serious missed diagnoses or ED revisits [18,20,21]. One survey of pediatric emergency medicine providers found that obtaining family buy-in on the diagnosis of constipation is the most common reason for obtaining plain radiographs [38]. Additionally, we found that radiograph use for children in general EDs had increased. This may also be due to the need for family buy-in, as well as other bar- riers to guideline adoption such as physician desire to reduce diagnostic uncertainty [39]. The uncertainty is in part due to abdominal pain being a frequent chief complaint in children [6,24], but neither a sensitive nor specific symptom for constipation [6].

We found that CT was used in 18-22% of all encounters with a diag-

nosis of constipation (Table 2). While there is no role for CT imaging in the diagnosis of constipation, it is possible that these encounters had concomitant diagnoses or required the evaluation of appendicitis, diver- ticulitis and other intraabdominal processes before arriving at the diag- nosis of constipation. Past work has shown that for non-traumatic abdominal pain, general EDs had higher rate of CT while pediatric EDs had higher rate of ultrasound, likely due to evaluation for appendicitis, intussusception, and Ovarian torsion [40]. These findings suggest that general EDs may be performing CTs more frequently on children due to lack of ultrasound availability. This also represents opportunities to enhance provider awareness of pediatric-focused radiology protocols

Table 3

Emergency department diagnostic tests and management for constipation, by age and year intervals.

Age groups

Year intervals

0-18% (SE)

19-40% (SE)

41-60% (SE)

>60% (SE)


2006-2008% (SE)

2009-2011% (SE)

2012-2014% (SE)

2015-2017% (SE)


Laboratory testing


13 (1.5)

31 (2.6)

39 (3.0)

38 (2.5)


26 (2.5)

25 (2.2)

11 (1.8)

44 (2.6)

< 0.0001


26 (2.1)

56 (3.1)

61 (3.4)

58 (2.9)


45 (2.6)

48 (2.5)

47 (3.1)

46 (2.7)



39 (2.3)

56 (3.1)

50 (2.9)

42 (2.8)


41 (2.2)

43 (2.4)

47 (2.8)

48 (3.4)



Any imaging

58 (2.2)

67 (2.8)

72 (2.8)

71 (2.5)


61 (2.4)

66 (2.4)

64 (2.4)

70 (2.6)



48 (2.3)

44 (3.2)

46 (3.4)

50 (2.6)


46 (2.6)

49 (2.3)

41 (2.6)

52 (2.8)



5.2 (1.1)

7.7 (1.4)

4.2 (1.1)

3.8 (1.0)


3.6 (0.83)

4.5 (0.9)

7.2 (1.4)

4.7 (1.0)



9.2 (1.5)

22 (2.6)

29 (2.8)

30 (2.2)


18 (2.0)

21 (2.1)

20 (2.4)

22 (2.2)


Managementa – in ED or on discharge

Osmotic laxative 28 (2.3) 16 (2.4) 18 (2.7) 13 (1.4) <0.0001 12 (1.7) 24 (2.2) 20 (2.7) 21 (2.4) 0.18

a Unable to compare rates of MRI, stimulant laxatives, stool softener, bulking agents and enema due to unreliable estimates.

to minimize unnecessary radiation exposure in children [40,41]. Overall, our findings, along with prior work, point to opportunities to expand on institutional efforts to reduce diagnostic imaging for suspected con- stipation, as well as to disseminate evidence on the successful efforts [18-21].

In the management of constipation, we found that osmotic laxatives – mostly represented by polyEthylene glycol (PEG) – were the most fre- quently prescribed medications for constipation. For adults with chronic constipation, there is moderate evidence and strong recommendation in favor of PEG over other drug classes [10,42]. There is mixed evidence for stimulant laxatives as a rescue option [39]. For children with chronic constipation, evidence points to equal effectiveness of PEG and enemas for fecal disimpaction, but PEG is preferentially recommend given the ease of oral administration [7]. For both adults and children, the quality of evidence for other drug classes was low due to the heterogeneity of the available studies [7,10,42,43]. One single-center study found that a significant number of children were started on therapy after ED visit for constipation [44]. This suggests that the ED visit was useful in either identifying the previously unknown problem or highlighted the severity of the problem. One multicenter retrospective cohort study found that children who were administered enema were not only more likely to revisit the ED, but also more likely to be given an alternate diagnosis to constipation at the revisit [5]. This suggests that if there are signs and symptoms that prompt enema administration, there may be clinical features that help identify clinically important alternate diagnoses [5].

We found that general EDs were less likely than pediatric EDs to pre- scribe osmotic laxatives to children. However, we also found an increase in osmotic laxative use in general EDs for children from 2006 to 2017, suggesting growing awareness and perhaps adoption of the guidelines [7]. It is also possible that after PEG became available over-the-counter in 2007, there was increasing public awareness of the medication which led to the increased prescription rate. Nevertheless, despite the evidence and Guideline recommendations, the osmotic laxative rate in children was only 28% overall in all EDs and 37% in pediatric EDs. It is possible that patients already had access to PEG over the counter or from prior prescriptions. Another explanation is the wide variation in care due to local practice patterns [15]. Practice variation has also been found within a single pediatric ED, as well as a low rate (35%) of adherence to laxative prescriptions after discharge [45]. Furthermore, most of the available evidence apply to outpatient maintenance therapy, not ED treatment of acutely symptomatic constipation [7,15,43,46]. Further research is therefore needed to delineate the opti- mal ED treatment and discharge regimen.

    1. Limitations

Our study is bound by the limitations of the NHAMCS which include under-reporting, sampling errors, and evolution of the survey fields over time [26,47,48]. To address the evolution of the survey fields, we examined all relevant survey fields during data analysis and harmo- nized the data over the years [26,47]. For example, the low rate of elec- trolytes in 2012-2014 is likely due to underreporting. It is possible that the “Electrolytes” field in the survey [49] was not marked as the test be- came increasingly referred to as metabolic panel, basic metabolic panel (BMP) and comprehensive metabolic panel (CMP). We observed a sig- nificant increase in electrolyte testing with the introduction of the BMP and CMP fields to the survey in 2015. We did not identify any other survey or sampling methodology changes to account for the low rate of electrolytes in the 2012-2014 period [49,50].

Our study is also limited by the retrospective, encounter-based na- ture of the data; we were unable to obtain patient-level information such as prior or subsequent ED or outpatient visits for constipation. The number of unweighted ED encounters ranged from 16,709 to 35,849 annually. This limited more granular year-to-year comparisons and, even when grouped in 3-year intervals, our analyses were limited by relative standard errors >30% [26].

Because the radiograph field in the survey does not specify the body part(s) imaged, it is possible that our findings are confounded by X-rays obtained for concurrent pulmonary processes. From 2008 to 2018, there has been a significant decrease in Chest x-ray use in pediatric EDs in the United States [51]. This suggests the radiograph trend we observed represents a true constant rate of abdominal radiographs, and perhaps even an increased rate if corrected for the decreasing rate of CXR.

  1. Conclusion

There has been a significant increase in ED visits for adults and chil- dren with constipation in the US from 2006 to 2017. The use of diagnos- tic tests and medications has not changed significantly despite evidence that constipation is a clinical diagnosis requiring consistent outpatient management. Local quality improvement initiatives have decreased ra- diograph use, for example, without effecting similar changes outside the environments in which they were initially developed. To our knowl- edge, no large-scale improvement collaboratives have addressed consti- pation. Evidence from other disease processes, such as bronchiolitis, suggests that such large-scale collaboratives can successfully imple- ment guideline-based care across multiple institutions [28,52,53].

Our findings highlight opportunities to reduce ED resource utili- zation through patient and provider education, as well as local and collaborative quality improvement initiatives beyond individual institutions. They also reinforce the importance of effective outpa- tient follow up and treatments through knowledge dissemination and implementation.

Financial support


Author contributions

A.Z.Z. was responsible for planning the study, conducting the study, collecting the data, interpreting the data, drafting the manuscript, and revising the manuscript. D.L. was responsible for conducting the study, analyzing the data, interpreting the data, and revising the manuscript.

N.J.S. were responsible for conducting the study, collecting the data, in- terpreting the data and revising the manuscript. T.A.F. was responsible for planning the study, conducting the study, interpreting the data, re- vising the manuscript, and supervising the study. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

CrediT authorship contribution statement Amy Z. Zhou: Data curation, Formal analysis, Investigation, Method-

ology, Project administration, Writing – original draft, Writing – review & editing. Douglas Lorenz: Writing – review & editing, Software, Meth- odology, Formal analysis, Data curation. Norma-Jean Simon: Writing – review & editing, Software, Methodology, Data curation, Conceptualiza- tion. Todd A. Florin: Writing – review & editing, Supervision, Methodol- ogy, Formal analysis, Conceptualization.

Declaration of Competing Interest

The authors have no conflicts of interest to disclose.

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi. org/10.1016/j.ajem.2022.01.065.


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