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World Journal of
Gastrointestinal Endoscopy
ISSN 1948-5190 (online)
World J Gastrointest Endosc 2022 August 16; 14(8): 474-511
Published by Baishideng Publishing Group Inc
WJGE https://www.wjgnet.com IAugust 16, 2022 Volume 14 Issue 8
World Journal of
Gastrointestinal
Endoscopy
W J G E
Contents Monthly Volume 14 Number 8 August 16, 2022
ORIGINAL ARTICLE
Retrospective Cohort Study
Disparities in colonoscopy utilization for lower gastrointestinal bleeding in rural vs urban settings in the
United States
474
Ganta N, Aknouk M, Alnabwani D, Nikiforov I, Bommu VJL, Patel V, Cheriyath P, Hollenbeak CS, Hamza A
Retrospective Study
Percutaneous transluminal angioplasty balloons for endoscopic ultrasound-guided pancreatic duct
interventions
487
AbiMansour JP, Abu Dayyeh BK, Levy MJ, Storm AC, Martin JA, Petersen BT, Law RJ, Topazian MD, Chandrasekhara V
Observational Study
New application of endocytoscope for histopathological diagnosis of colorectal lesions
495
Inoue F, Hirata D, Iwatate M, Hattori S, Fujita M, Sano W, Sugai T, Kawachi H, Ichikawa K, Sano Y
CASE REPORT
Hidden local recurrence of colorectal adenocarcinoma diagnosed by endoscopic ultrasound: A case series
502
Okasha HH, Wahba M, Fontagnier E, Abdellatef A, Haggag H, AbouElenin S
LETTER TO THE EDITOR
Laparoscopic and endoscopic cooperative surgery for full-thickness resection and sentinel node dissection
for early gastric cancer
508
Vanella S, Godas M, Pereira JC, Pereira A, Apicella I, Crafa F
WJGE https://www.wjgnet.com II August 16, 2022 Volume 14 Issue 8
World Journal of Gastrointestinal Endoscopy
Contents Monthly Volume 14 Number 8 August 16, 2022
ABOUT COVER
Editorial Board Member of World Journal of Gastrointestinal Endoscopy, Murali Dharan, FASGE, MRCP, Assistant
Professor, Department of Gastroenterology and Hepatology, University of Connecticut Health Center, Farmington,
CO 06030, United States. dharan@uchc.edu
AIMS AND SCOPE
The primary aim of World Journal of Gastrointestinal Endoscopy (WJGE, World J Gastrointest Endosc) is to provide
scholars and readers from various fields of gastrointestinal endoscopy with a platform to publish high-quality basic
and clinical research articles and communicate their research findings online.
WJGE mainly publishes articles reporting research results and findings obtained in the field of gastrointestinal
endoscopy and covering a wide range of topics including capsule endoscopy, colonoscopy, double-balloon
enteroscopy, duodenoscopy, endoscopic retrograde cholangiopancreatography, endosonography, esophagoscopy,
gastrointestinal endoscopy, gastroscopy, laparoscopy, natural orifice endoscopic surgery, proctoscopy, and
sigmoidoscopy.
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Journal Citation Indicator (JCI) for WJGE as 0.33.
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Submit a Manuscript: https://www.f6publishing.com World J Gastrointest Endosc 2022 August 16; 14(8): 474-486
DOI: 10.4253/wjge.v14.i8.474 ISSN 1948-5190 (online)
ORIGINAL ARTICLE
Retrospective Cohort Study
Disparities in colonoscopy utilization for lower gastrointestinal
bleeding in rural vs urban settings in the United States
Nagapratap Ganta, Mina Aknouk, Dina Alnabwani, Ivan Nikiforov, Veera Jayasree Latha Bommu, Vraj Patel,
Pramil Cheriyath, Christopher S Hollenbeak, Alan Hamza
Specialty type: Gastroenterology
and hepatology
Provenance and peer review:
Unsolicited article; Externally peer
reviewed.
Peer-review model: Single blind
Peer-review report’s scientific
quality classification
Grade A (Excellent): 0
Grade B (Very good): B
Grade C (Good): C, C
Grade D (Fair): 0
Grade E (Poor): 0
P-Reviewer: El-Nakeep S, Egypt;
Govindarajan KK, India;
Thomopoulos K, Greece
Received: February 15, 2022
Peer-review started: February 15,
2022
First decision: April 12, 2022
Revised: May 14, 2022
Accepted: July 22, 2022
Article in press: July 22, 2022
Published online: August 16, 2022
Nagapratap Ganta, Mina Aknouk, Dina Alnabwani, Ivan Nikiforov, Veera Jayasree Latha Bommu,
Vraj Patel, Pramil Cheriyath, Department of Internal Medicine, Hackensack Meridian Health
Ocean Medical Center, Brick, NJ 08724, United States
Christopher S Hollenbeak, Penn State Milton S. Hershey Medical Center, 500 University Drive,
University Park, PA 16802, United States
Alan Hamza, Department of Internal Medicine, Ocala Health, Ocala, FL 34471, United States
Corresponding author: Pramil Cheriyath, FACP, MBBS, MD, MS, Director, Doctor,
Department of Internal Medicine, Hackensack Meridian Health Ocean Medical Center, 1610
NJ-88, Brick, NJ 08724, United States. pramil.cheriyath@hmhn.org
Abstract
BACKGROUND
Lower gastrointestinal bleeds (LGIB) is a very common inpatient condition in the
United States. Gastrointestinal bleeds have a variety of presentations, from minor
bleeding to severe hemorrhage and shock. Although previous studies investigated
the efficacy of colonoscopy in hospitalized patients with LGIB, there is limited
research that discusses disparities in colonoscopy utilization in patients with LGIB
in urban and rural settings.
AIM
To investigate the difference in utilization of colonoscopy in lower gastrointestinal
bleeding between patients hospitalized in urban and rural hospitals.
METHODS
This is a retrospective cohort study of 157748 patients using National Inpatient
Sample data and the Healthcare Cost and Utilization Project provided by the
Agency for Healthcare Research and Quality. It includes patients 18 years and
older hospitalized with LGIB admitted between 2010 and 2016. This study does
not differentiate between acute and chronic LGIB and both are included in this
study. The primary outcome measure of this study was the utilization of
colonoscopy among patients in rural and urban hospitals admitted for lower
gastrointestinal bleeds; the secondary outcome measures were in-hospital
mortality, length of stay, and costs involved in those receiving colonoscopy for
LGIB. Statistical analyses were all performed using STATA software. Logistic
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 475 August 16, 2022 Volume 14 Issue 8
regression was used to analyze the utilization of colonoscopy and mortality, and a generalized
linear model was used to analyze the length of stay and cost.
RESULTS
Our study found that 37.9% of LGIB patients at rural hospitals compared to approximately 45.1%
at urban hospitals received colonoscopy, (OR = 0.730, 95%CI: 0.705-0.7, P > 0.0001). After
controlling for covariates, colonoscopies were found to have a protective association with lower in-
hospital mortality (OR = 0.498, 95%CI: 0.446-0.557, P < 0.0001), but a longer length of stay by 0.72 d
(95%CI: 0.677-0.759 d, P < 0.0001) and approximately $2199 in increased costs.
CONCLUSION
Although there was a lower percentage of LGIB patients that received colonoscopies in rural
hospitals compared to urban hospitals, patients in both urban and rural hospitals with LGIB
undergoing colonoscopy had decreased in-hospital mortality. In both settings, benefit came at a
cost of extended stay, and higher total costs.
Key Words: Lower gastrointestinal bleeding; Rural-urban disparities; Colonoscopy; Utilization of
colonoscopy; Length of stay; Inpatient admission costs
©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
Core Tip: Colonoscopy utilization is lower in rural hospitals than in urban hospitals in the United States for
all acute and chronic lower gastrointestinal bleeding. Patients in both rural and urban hospitals who
present with lower gastrointestinal bleeds that undergo colonoscopy have decreased in-hospital mortality,
an extended length of hospital stay, and higher total costs.
Citation: Ganta N, Aknouk M, Alnabwani D, Nikiforov I, Bommu VJL, Patel V, Cheriyath P, Hollenbeak CS,
Hamza A. Disparities in colonoscopy utilization for lower gastrointestinal bleeding in rural vs urban settings in the
United States. World J Gastrointest Endosc 2022; 14(8): 474-486
URL: https://www.wjgnet.com/1948-5190/full/v14/i8/474.htm
DOI: https://dx.doi.org/10.4253/wjge.v14.i8.474
INTRODUCTION
Gastrointestinal (GI) bleeding is the most common cause of hospitalization due to gastrointestinal
disease in the United States and is responsible for 2%-4% of hospital mortality[1]. Approximately 30% to
40% of all cases of GI bleeding are from a lower GI source[2]. Over the past decade, there has been a
progressive change in GI bleeding patterns that lead to hospitalization, with a clear decreasing trend in
upper GI events and a significant increase in lower GI events[3]. Unfortunately, even though lower
gastrointestinal bleeding (LGIB) is a common indication for admission to the hospital, it has received
relatively little attention in the literature[4]. The estimated hospitalization rate for LGIB is 33-87 per
100000 population[3] with mortality rates of 2%-4% during hospitalization and rebleeding rates of 13%-
19% after one year[4] . Diverticular bleeds are the leading cause of LGIB and account for approximately
30%-50% of all cases[5]. In patients 50 years or younger, the leading cause of LGIB is hemorrhoids,
which often present as minor bleeding. Increased incidence of LGIB with age is likely secondary to
increased diverticulosis and angiodysplasia[1]. Other conditions that are commonly associated with
LGIB include angiodysplasia, ischemic colitis, colon cancer/polyps, post-polypectomy bleeding, inflam-
matory bowel disease, solitary rectal ulcer, radiation colitis/proctitis, and rectal varices[6]. Colonoscopy
is a minimally invasive procedure that improves clinical outcomes which include- decreased rebleeding,
decreased duration of hospital stay, and decreased need for major surgery[7].
Primary intervention in diagnosing LGIB is receiving a colonoscopy and it is important that the
procedure is performed with minimal delay[8]. Currently the large majority of diagnostic and
therapeutic procedures in Gastroenterology is the colonoscopy. In 2015, approximately 11.5 million
colonoscopies were performed compared to 6.1 million upper endoscopies and a significantly lower rate
of flex sigmoidoscopies at 313000 annually[2]. Urgent Golytely preparation and colonoscopy is the most
direct and cost effective approach to diagnose hematochezia[7].
Several factors might contribute to rural-urban disparities in utilizing colonoscopy. Major factors may
be rural provider distribution and scarcity, challenges that have persisted despite significant attempts
by federal and state governments to address them over the last three decades[9]. The increased disparity
is also linked to fewer specialist visits and a greater reliance on generalists in rural regions. Therefore,
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 476 August 16, 2022 Volume 14 Issue 8
examining differences in rural hospitals and the benefits of colonoscopy among patients with lower
gastrointestinal bleeds can lead to better patient outcomes.
This study is aimed to determine whether there were rural disparities in colonoscopy utilization in
hospitalized patients with lower GI bleeding (LGIB) and the benefits of receiving a colonoscopy.
MATERIALS AND METHODS
Study design
This is a retrospective cohort study.
Data source
Data used in this study were from the National Inpatient Sample (NIS), Healthcare Cost and Utilization
Project (HCUP), provided by the Agency for Healthcare Research and Quality (AHRQ). The NIS is the
most extensive all-payer administrative discharge data set in the US and contains information on
discharges from community hospitals[10]. Cohorts of hospitalized patients can be identified in the NIS
using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9) codes
for the third quarter of 2015 and earlier, and International Classification of Diseases, Tenth Revision,
Clinical Modification (ICD-10) codes for the fourth quarter of 2015 and later.
Cohort
This study examined 157748 patients from the United States aged 18 and older in the NIS hospitalized
with a principal diagnosis of LGIB between 2010 and 2016. There is no differentiation between acute or
chronic bleeding. The algorithm described by Strate et al[4] was used to define the cohort. While Strate et
al[4] defines a cohort of patients with LGIB ICD-9 diagnosis and procedure codes, the general
equivalence mappings (GEM) from the Centers for Medicare and Medicaid Services (CMS) were used to
extend their algorithm to ICD-10 diagnosis and procedural classification system (PCS) codes[11-13].
Patients with a principal ICD-9 diagnosis code indicating lower gastrointestinal bleeding were
included in the cohort, including 562.12 (Diverticulosis of colon with hemorrhage), 562.13 (Diverticulitis
of colon with hemorrhage), 569.85 (Angiodysplasia of the intestine with bleeding), 569.3 (Hemorrhage
of rectum and anus), 455.2 (Internal hemorrhoids with other complication), 455.5 (External hemorrhoids
with further complication) and 455.8 (Unspecified hemorrhoids with other complication). We also
included patients with a secondary ICD-9 code that indicated a source of bleeding in the lower
gastrointestinal tract (Supplementary material). Furthermore, patients were excluded if the source of
bleeding appeared to be in the upper gastrointestinal tract or if they had an ICD-9 procedure code or
ICD-10 PCS code suggestive of a surgical procedure in the upper gastrointestinal tract or small intestine.
ICD-9 diagnosis and procedure codes were used for inclusion or exclusion criteria, and comparable
ICD-10 codes are listed in Supplementary material. Since we have based our study on administrative
data obtained from NIS, which is further based purely on ICD codes, we cannot comment with certainty
as to the clinical details on why colonoscopy was not done in some patients with LGIB and if any other
diagnostics were used. A study based on a medical chart review would be able to better answer the
questions related to the final diagnosis or cause of LGIB or why colonoscopy was not done in some
patients, and we would definitely want to conduct a study in the future to analyze these details.
The primary outcome of this study was the utilization of colonoscopy. This was identified using a
principle or secondary ICD-9 procedure code of 45.23 (colonoscopy) or a principle or secondary ICD-10
PCS code of 0DJD8ZZ (Inspection of Lower Intestinal Tract, Via Natural or Artificial Opening
Endoscopic). In addition, three secondary outcomes were studied, including in-hospital mortality,
length of stay, and costs. Length of stay was defined as total days from admission to discharge or death.
Costs were estimated from the hospital perspective from hospital-level ratios of costs-to-charges. All
charges were adjusted to the year 2018 US dollars using the medical care component of the consumer
price index.
Covariates
All multivariable analyses controlled for the patient and hospital characteristics. Models controlled for
age (18-64, 65-74, 75-84, 85+), sex (male, female), race (white, black, Hispanic, Asian, other), and primary
payer (Medicare, Medicaid, commercial, other). We controlled the size of the hospital (small, medium,
large) and the teaching status of the hospital. Teaching hospitals have at least one Accreditation Council
for Graduate Medical Education (ACGME) approved residency program or are members of the Council
of Teaching Hospitals (COTH). Comorbidities were controlled using the Charlson Comorbidity Index, a
weighted index of 17 comorbidities[14,15]. Finally, we controlled for the geography of the hospital
(rural, urban). Geography was based on the county where the hospital is located. Rural hospitals were
identified as those located in counties with a core-based statistical area designated as micropolitan or
non-core. This classification of rural-urban is based on the site’s zip code.
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 477 August 16, 2022 Volume 14 Issue 8
Statistical analysis
Statistical analyses were designed to determine whether there was a significant association between
rural hospital designation and utilization of colonoscopy among patients admitted for gastrointestinal
bleeding. In addition, we tested whether patients who received colonoscopy had significantly different
rates of in-hospital mortality, length of hospital stay, and hospital costs. Characteristics of patients were
compared between those who received care at rural vs urban hospitals using t-tests for continuous
variables and chi-square tests for binary and categorical variables. Utilization of colonoscopy was
modeled using logistic regression, controlling for patient and hospital characteristics. Mortality was also
modeled using logistic regression. Length of stay and costs were modeled using linear regression,
controlling for patient and hospital characteristics. A propensity score analysis matched patients who
received care at a rural hospital to those at an urban hospital. Matching was performed using a 1:1
nearest neighbor approach and a caliper restriction of 0.2 times the standard deviation. Statistical
analyses were performed using STATA software (version 15, College Station, TX, United States).
Statistical significance was defined as P < 0.05.
RESULTS
Rates of colonoscopy utilization stratified by rurality are presented in Figure 1. Approximately 37.9% of
patients with lower gastrointestinal bleeding received colonoscopy at rural hospitals compared to 45.1%
at urban hospitals. Rural hospitals had a consistently lower rate of colonoscopy utilization relative to
urban hospitals from 2010 through 2015. The difference was mediated to a large degree in 2016. Also,
there was a trend for decreasing colonoscopy utilization in both settings.
As seen in Table 1, patients differed significantly in demographics and comorbidities. However,
much of the significance was due to the considerable sample size. For example, patients treated at rural
hospitals tended to be slightly older (74.4 years vs 73.0 years, P < 0.0001), more likely to be female (53.7%
vs 51.9%, P < 0.0001), and significantly more likely to be white (74.6% vs 63.9%). Instead of other payers,
they were more likely to be insured by Medicare (78.8% vs 74.3%). Hospital characteristics also differed
significantly. For example, all rural hospitals are non-teaching hospitals, and bed size varies by region
and rurality in the NIS[10]. A large hospital in a rural area in the Northeast has 100 or more beds, while
a large, urban teaching hospital has 425 or more beds. A large hospital in a rural area in the West has 45
or more beds, while a large, urban teaching hospital has 325 or more beds.
After controlling for other factors, patients treated at rural hospitals had 27% lower odds of receiving
colonoscopy relative to patients treated at urban hospitals (OR = 0.73, P < 0.0001) (Table 2). There were
several other factors associated with receiving a colonoscopy. For example, women had 4.4% lower
odds of receiving colonoscopy (OR = 0.96, P < 0.0001), and non-white patients were more likely to
receive a colonoscopy. Patients with more comorbidities were less likely to receive colonoscopy; each
additional one-point increase in the Charlson comorbidity index was associated with 5.1% lower odds of
colonoscopy. Patients who were receiving care at small (OR = 0.90, P < 0.0001) and medium (OR = 0.92)
sized hospitals were less likely to receive colonoscopy relative to patients receiving care at large
hospitals.
Patients who received colonoscopy had a significantly lower likelihood of in-hospital mortality
(Table 3). After controlling for other factors, colonoscopy was associated with a 50% lower odds of
mortality (OR = 0.50, P < 0.0001). In addition, patients treated at rural hospitals had a 5% greater odds of
mortality (OR = 1.05, P = 0.58), but this association was not statistically significant after controlling for
colonoscopy utilization. Several other factors were associated with more significant in-hospital
mortality, including age and comorbidities. Other factors were protective for mortality, including the
female sex, which was associated with 17% lower odds of mortality (OR = 0.83, P < 0.0001).
Utilization of colonoscopy was associated with a longer length of hospital stay of 0.72 days (P <
0.0001) (Table 4). In addition, patients treated at rural hospitals had a shorter stay of 0.37 d (P < 0.0001).
Colonoscopy was also associated with higher hospital costs. Patients treated at rural hospitals incurred
lower costs of $853 (P < 0.001) independent of colonoscopy. Patients admitted for lower gastrointestinal
bleeding who received colonoscopy incurred an additional $2,199 in costs (P < 0.0001) (Table 5).
To control for potential selection bias in patients receiving treatment at rural hospitals, a propensity
score matching analysis was used to match 16177 patients treated at rural hospitals with 16177 similar
patients treated at urban hospitals. After matching, there were no significant differences in inpatient or
hospital characteristics. Results of the propensity score analysis confirmed the multi-variable model. In
the overall (unmatched) cohort, 37.9% of patients treated at rural hospitals received a colonoscopy,
while 46% of patients treated at urban hospitals received a colonoscopy (P < 0.0001). After matching,
44.7% of patients treated at urban hospitals received colonoscopy (P < 0.0001), suggesting that the
utilization of colonoscopy between urban and rural hospitals is not related to patient characteristics.
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 478 August 16, 2022 Volume 14 Issue 8
Table 1 Characteristics of patients admitted for lower gastrointestinal bleeding, stratified by geography
Variable Urban (n = 141571) Rural (n = 16177) P value
Age 73.01 74.35 < 0.0001
18-64 24.2% 20.3%
65-74 22.2% 22.3%
75-84 27.6% 29.6%
85+ 22.9% 24.5%
Sex < 0.0001
Male 48.1% 46.3%
Female 51.9% 53.7%
Race < 0.0001
White 63.9% 74.6%
Black 18.5% 10.8%
Hispanic 8.2% 2.3%
Asian 2.7% 1.9%
Other 2.1% 1.0%
Missing 4.6% 9.4%
Payer < 0.0001
Medicare 74.3% 78.8%
Medicaid 5.4% 4.3%
Commercial 16.0% 12.4%
Other 4.3% 4.4%
Missing 0.1% 0.3%
Comorbidities
Number 1.38 1.32 < 0.0001
Charlson index 1.89 1.77 < 0.0001
Colonoscopy < 0.0001
Yes 45.1% 37.9%
No 54.9% 62.1%
Hospital bed size < 0.0001
Small 15.5% 10.8%
Medium 29.5% 18.9%
Large 54.9% 70.2%
Region < 0.0001
Northeast 33.2% 21.8%
Midwest 44.2% 20.8%
South 50.0% 39.9%
West 28.4% 17.4%
Teaching < 0.0001
No 45.5% 100.0%
Yes 54.5% 0.0%
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 479 August 16, 2022 Volume 14 Issue 8
DISCUSSION
Patients who present with gastrointestinal bleeds should undergo a thorough history, physical
examination, lab work, and diagnostic procedure to determine the source of bleeding (upper GI tract,
colon, or small bowel) and identify the pathology of the bleed. Colonoscopy is the most popular
procedure for diagnosing, risk stratifying, and treating colonic bleeding[16]. It is often challenging to
manage lower GI bleeding because of the wide variety of pathology that can lead to a lower
gastrointestinal bleed. With advancements in endoscopic technology it is modality of choice for lower
gastrointestinal bleeds as it allows for diagnosis and treatment simultaneously[17]. Approximately 15%
of patients with presumed LGIB are ultimately found to have an upper GI source for their bleeding,
highlighting the importance of receiving a timely colonoscopy[18].
Our study demonstrates that patients with LGIB admitted to rural hospitals are less likely to receive
colonoscopy for the diagnosis and management, with an odds ratio of 0.73 (95%CI: 0.71-0.76, P <
0.0001). Results also showed that the disparity gap has narrowed over the past few years, but we should
continue to improve availability of colonoscopy in rural hospitals.
Colonoscopy utilization in rural vs. urban LGIB patients could be due to several factors. One of the
major factors is the lack of specialists, such as gastroenterologists, in rural hospitals. For this reason,
colonoscopies in hospitals that are short on subspecialists are often performed by family medicine
physicians that are trained in the procedure. Despite the lower rate of colonoscopies, the safety and
quality of family physicians performing colonoscopies are highly comparable to specialists performing
the same procedure[19]. These findings suggest that increasing the training opportunities for family
physicians in performing colonoscopies could potentially alleviate the scarcity of subspecialists in rural
hospitals. Rural provider distribution and scarcity challenges have persisted despite significant attempts
by federal and state governments to address them over the last three decades[9].
Lack of insurance and the barrier of financial hardship in rural populations may also partly explain
the lower rate of colonoscopies performed in rural hospitals. The disproportion of colonoscopies
performed in rural vs urban hospitals does however show a downward trend after implementing the
Affordable Care Act (ACA)[20]. Insufficient public transportation and increased distance and time to
travel to urban hospitals to get colonoscopy and specialist health care can also explain the lower rates of
colonoscopy utilization in rural patients. Access to primary care is one of the most significant determ-
inants of up-to-date screening status. However, cost barriers and other factors such as poor broadband
internet services limit rural residents' access to finding a primary provider[21].
According to the United States census bureau, in 2017, rural counties continued to have higher
uninsured residents than urban areas. In entirely rural counties, 12.3% of the population lacked health
insurance, compared to 11.3 percent in primarily rural counties (more than half of the people in rural
areas) and 10.1 percent in most urban counties (less than half of the population in rural areas)[22].
According to the Medical Expenditure Panel Survey (MEPS), in 2014-2015, 37.0% of rural people and
33.6% of urban people aged 65 years and older were covered by medicare[23].
In a cross-sectional analysis of Center for Disease Control (CDC) data by Cole et al[24], rural residents
had lower colorectal cancer screening rates (48%; 95%CI: 48%-49%) than urban residents (54%; 95 %CI:
53%- 55%) from 1998 to 2005 after accounting for demographic and health factors. However, the total
number of colonoscopy or flexible sigmoidoscopy screenings increased in urban and rural populations
from 1998 to 2005[24]. The rural disparity is also shown in a systematic review by Castellanos et al[21],
who examined studies of patients suffering from cardiovascular diseases between 1990 and 2017. Most
published clinical trials showed that patients from rural communities had significantly lower cardiac
rehabilitation referral and participation rates than the general population[21].
Our study also showed that older people aged 85 years and above with LGIB were less likely to
receive a colonoscopy, perhaps because current guidelines do not recommend routine screening after 75
years. Women with LGIB are less likely to receive a colonoscopy, most likely because lower GI bleeding
is more common in men than in women, and men are more likely to undergo colonoscopy[25]. A study
by Devani et al[26] showed that women were more likely to delay colonoscopy than males, and women
were more likely to ignore bleeding than men (Table 2).
The odds of mortality were reduced in all patients who received a colonoscopy, irrespective of rural
or urban location, and the mortality was not significantly different in rural and urban hospitals for
patients who received a colonoscopy. This supports our observation that colonoscopy utilization is
associated with decreased mortality in all patients, and thus it should be offered to all LGIB patients. As
shown in our study, there is, however, a statistically significant difference in colonoscopy utilization
between rural and urban hospitals. Thus, by increasing colonoscopy availability in rural hospitals, we
anticipate a reduction in mortality in rural hospitals. In general, rural populations in the United States
are, on average, older and sicker than their urban counterparts[27]. Our study demonstrates that
patients with lower gastrointestinal bleeds who underwent colonoscopy had significantly lower
mortality than those with LGIB who did not undergo colonoscopy. This effect was observed after
controlling for meaningful patient and hospital characteristics (Table 3). This highlights the significant
impact colonoscopy can play in patients with LGIB.
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 480 August 16, 2022 Volume 14 Issue 8
Table 2 Results of multivariable model of colonoscopy utilization
95%CI
Variable OR Lower Upper P value
Rural 0.730 0.705 0.757 < 0.0001
Age
18-64 Reference
65-74 0.978 0.946 1.010 0.177
75-84 0.986 0.954 1.018 0.384
85+ 0.826 0.798 0.855 < 0.0001
Sex
Male Reference
Female 0.956 0.937 0.976 < 0.0001
Race
White Reference
Black 1.224 1.191 1.258 < 0.0001
Hispanic 1.206 1.160 1.253 < 0.0001
Asian 1.222 1.148 1.301 < 0.0001
Other 1.158 1.078 1.244 < 0.0001
Missing 1.107 1.057 1.159 < 0.0001
Payer
Medicare Reference
Medicaid 0.986 0.938 1.037 0.590
Commercial 1.068 1.034 1.103 < 0.0001
Other 1.076 1.020 1.135 0.007
Missing 0.763 0.579 1.004 0.053
Hospital bed size
Small 0.899 0.873 0.925 < 0.0001
Medium 0.919 0.898 0.940 < 0.0001
Large Reference
Teaching
No Reference
Yes 0.951 0.931 0.972 < 0.0001
Charlson comorbidity index 0.949 0.944 0.955 < 0.0001
Patients aged 85 years and above with LGIB had higher mortality rates than patients aged 18-64
years. This may partly be explained by the fact that current guidelines do not recommend routine
screening after the age of 75 years, and also, they have confounding prognostic factors compared to
younger patients (Table 3). Other research has shown that independent predictors of in-hospital
mortality include age, intestinal ischemia, comorbid illness, bleeding while hospitalized for a separate
process, coagulation defects, hypovolemia, transfusion of packed red blood cells, and male gender[4].
Women with LGIB had lower mortality rates than men regardless of the treatment setting. These
results were comparative to a retrospective observational study by Devani et al[26], who found that the
odds of mortality were almost 17% lower in women with LGIB than in men.
Our study showed that patients with LGIB admitted to rural hospitals had 8 to 9 h (0.37 d) shorter
length of hospital stay than patients admitted to urban hospitals. This can be due to the likelihood that
rural populations were less likely to undergo colonoscopy, which extends admissions, as rural hospitals
have fewer resources and specialists to perform colonoscopies. Rural populations may also get
discharged earlier due to poor insurance benefits and higher inpatient admission costs. Most rural
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 481 August 16, 2022 Volume 14 Issue 8
Table 3 Multivariable model of mortality
95%CI
Variable OR Lower Upper P value
Rural 1.050 0.888 1.242 0.567
Colonoscopy
Yes 0.498 0.446 0.557 < 0.0001
No Reference
Age
18-64 Reference
65-74 0.939 0.780 1.130 0.504
75-84 1.333 1.121 1.584 0.001
85+ 2.132 1.797 2.530 < 0.0001
Sex
Male Reference
Female 0.828 0.749 0.915 < 0.0001
Race
White Reference
Black 0.961 0.835 1.106 0.579
Hispanic 0.694 0.556 0.867 0.001
Asian 1.063 0.784 1.443 0.693
Other 0.960 0.665 1.385 0.826
Missing 0.944 0.750 1.187 0.621
Payer
Medicare Reference
Medicaid 0.941 0.718 1.235 0.662
Commercial 0.834 0.695 1.002 0.052
Other 0.774 0.556 1.077 0.129
Missing 0.538 0.074 3.905 0.540
Hospital bed size
Small 0.911 0.786 1.057 0.218
Medium 0.966 0.862 1.083 0.552
Large Reference
Teaching
No Reference
Yes 0.987 0.887 1.099 0.813
Charlson comorbidity index 1.239 1.215 1.263 < 0.0001
patients (37.01% of patients aged 65 years and older) have Medicare insurance[25] that has a prospective
payment system, which pays a predetermined, fixed reimbursement to the hospital for a diagnosis
irrespective of the length of stay. This payment system might prompt an earlier discharge for rural
patients[28].
Patients with LGIB undergoing colonoscopy had a longer length of hospital stay by 17 h (0.72 d) than
those who did not (Table 4). The length of time it takes to perform a colonoscopy is determined by the
patients’ and endoscopists’ characteristics. Even though not all colonoscopies are the same, there is no
distinction in the time permitted for each colonoscopy when arranging the procedure in the endoscopy
suite. As a result, patient wait times vary, impacting the overall length of stay. Factors determining the
length of stay (LOS) include overall time spent preparing for an operation, procedure time, insurance
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 482 August 16, 2022 Volume 14 Issue 8
Table 4 Multivariable model of length of hospital stay
95%CI
Variable Coefficient Lower Upper P value
Rural -0.372 -0.444 -0.300 < 0.0001
Colonoscopy
Yes 0.718 0.677 0.759 < 0.0001
No Reference
Age
18-64 Reference
65-74 0.133 0.066 0.201 < 0.0001
75-84 0.382 0.315 0.449 < 0.0001
85+ 0.518 0.448 0.588 < 0.0001
Sex
Male Reference
Female 0.067 0.026 0.109 0.001
Race
White Reference
Black 0.590 0.534 0.646 < 0.0001
Hispanic 0.016 -0.064 0.095 0.699
Asian -0.041 -0.169 0.088 0.534
Other 0.091 -0.057 0.238 0.227
Missing -0.183 -0.277 -0.089 < 0.0001
Payer
Medicare Reference
Medicaid -0.047 -0.150 0.055 0.367
Commercial -0.386 -0.453 -0.319 < 0.0001
Other -0.403 -0.513 -0.292 < 0.0001
Missing -0.079 -0.631 0.473 0.779
Hospital bed size
Small -0.451 -0.511 -0.391 < 0.0001
Medium -0.235 -0.283 -0.188 < 0.0001
Large Reference
Teaching
No Reference
Yes 0.297 0.253 0.341 < 0.0001
Charlson comorbidity index 0.232 0.221 0.243 < 0.0001
Intercept 3.173 3.097 3.249 < 0.0001
reimbursement, and out-of-pocket expenses, influencing hospital and patient decision-making[29].
Our study showed that rural patients with LGIB incur $853 less in costs than patients treated at urban
hospitals which could be due to the fact that rural patients are less likely to undergo colonoscopy, which
can be contributory to the reduction of the total inpatient admission cost.
Our study showed that patients with LGIB who undergo colonoscopy incur $2199 in higher costs
than those who do not. Procedural costs and longer duration of stay for patients undergoing
colonoscopy may be part of the higher costs. A cost-effectiveness analysis study comparing four
diagnostic strategies in the evaluation of rectal bleeding in adults by Allen et al[30] using a Markov
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 483 August 16, 2022 Volume 14 Issue 8
Table 5 Multivariable model of inpatient admission costs
95%CI
Variable Coefficient Lower Upper P value
Rural -$853.03 -$1059.62 -$646.44 < 0.0001
Colonoscopy
Yes $2198.68 $2080.08 $2317.27 < 0.0001
No Reference
Age
18-64 Reference
65-74 $353.75 $159.71 $547.79 < 0.0001
75-84 $569.47 $377.06 $761.87 < 0.0001
85+ $184.80 -$16.82 $386.42 0.072
Sex
Male Reference
Female -$487.40 -$606.30 -$368.49 < 0.0001
Race
White Reference
Black $1065.28 $903.76 $1226.81 < 0.0001
Hispanic $571.60 $343.11 $800.10 < 0.0001
Asian $2228.13 $1858.86 $2597.39 < 0.0001
Other $938.42 $514.93 $1361.92 < 0.0001
Missing -$223.19 -$492.88 $46.49 0.105
Payer
Medicare Reference
Medicaid $209.94 -$85.38 $505.27 0.164
Commercial -$432.66 -$624.55 -$240.77 < 0.0001
Other -$788.60 -$1105.57 -$471.62 < 0.0001
Missing -1065.893 -2652.626 520.839 0.188
Hospital bed size
Small -$418.08 -$590.47 -$245.70 < 0.0001
Medium -$305.15 -$440.76 -$169.54 < 0.0001
Large Reference
Teaching
No Reference
Yes $604.62 $477.91 $731.33 < 0.0001
Charlson comorbidity index $601.63 $570.19 $633.06 < 0.0001
Intercept $7859.86 $7642.30 $8077.41 < 0.0001
model showed that in addition to being associated with lower mortality, colonoscopy was also cost-
effective when compared to flexible sigmoidoscopy, flexible sigmoidoscopy followed by air contrast
barium enema (FS+ACBE), and simple observation. Additional research is needed to understand the
value proposition of colonoscopy for LGIB other than rectal bleeding. This is perhaps because patients
undergoing colonoscopy are more likely to stay longer in the hospital and spend higher costs than those
who do not undergo colonoscopy. Increases in LOS per day were linked to a 47% increase in Inpatient
admission costs[26]. The total cost of a colonoscopy depends on whether costs are assessed from a
societal or a health system perspective[31].
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 484 August 16, 2022 Volume 14 Issue 8
Figure 1 Trends in utilization of colonoscopy for patients admitted for lower gastrointestinal bleeding.
One strength of the study is that we used data from NIS, HCUP, provided by the AHRQ. This is a
nationally representative sample, which enhances the generalizability of our findings.
Limitations of the study
We could not account for the severity of LGIB or the screening status of patients. Also, we studied
admissions between 2010 and 2016 which is the most recent database and there is not currently more
recent data. A limitation is that the NIS data set is based solely on ICD-9 and ICD-10 diagnoses. Specific
colonoscopy findings are not reported in the NIS data set.
CONCLUSION
Our study results demonstrated that the rate of utilization of colonoscopy was significantly lower in
rural hospitals compared to urban hospitals. This study also showed that patients with lower
gastrointestinal bleeds undergoing colonoscopy had significantly lower in-hospital mortality than those
who did not. The study results emphasize the importance of counseling rural patients and educating
them about the life-threatening complications of LGIB, which colonoscopy can avoid. Furthermore we
would benefit from more access to colonoscopies in rural settings. Internal medicine and family
physicians should be trained to perform colonoscopies in rural settings to increase the availability of
colonoscopy in these areas. Physicians should be encouraged to improve rural population outreach,
hospital resources, and reimbursement. Despite differences in colonoscopy utilization, this study did
not show any significant difference in mortality between rural and urban patients with LGIB. Further
studies are needed to give more insights into rural-urban disparities in mortality.
ARTICLE HIGHLIGHTS
Research background
Disparities in colonoscopy access in rural and urban hospitals is an understudied topic. The significance
of this study is to demonstrate whether or not improved access improves patient mortality.
Research motivation
To improve access to colonoscopies in the United States. We are also interested in the availability of
colonoscopy and how it effects patients length of stay and costs.
Research objectives
To discover whether or not there is a disparity in colonoscopy utilization for lower gastrointestinal
bleeds between rural and urban hospital areas in the United States. Also to determine whether there is a
benefit for mortality in patients with lower gastrointestinal bleeds when they receive colonoscopies.
Ganta N et al. Colonoscopy rural vs urban over 6 years
WJGE https://www.wjgnet.com 485 August 16, 2022 Volume 14 Issue 8
Research methods
Retrospective cohort study and data analysis of National Inpatient Sample, Healthcare Cost and
Utilization Project, provided by the Agency for Healthcare Research and Quality.
Research results
Approximately 37.9% of patients with lower gastrointestinal bleeding received colonoscopy at rural
hospitals compared to 45.1% at urban hospitals. Patients treated at rural hospitals had 27% lower odds
of receiving colonoscopy relative to patients treated at urban hospitals (OR = 0.73, P < 0.0001) After
controlling for other factors, colonoscopy was associated with a 50% lower odds of mortality (OR = 0.50,
P < 0.0001). The problem that remains to be solved is providing patients in rural hospitals access to
colonoscopy so more patients can have a mortality benefit when they present with a lower
gastrointestinal bleed.
Research conclusions
This study proposes that because there is a decrease in mortality when patients receive a colonoscopy,
we should improve access to colonoscopies in rural hospitals. New methods proposed are increased
access to specialists and increased training opportunities for primary care providers for colonoscopies.
Research perspectives
Future research should be aimed at determining mortality differences in patients with lower
gastrointestinal bleeds that receive colonoscopy between urban and rural hospitals.
FOOTNOTES
Author contributions: Ganta N and Aknouk M contributed equally to this work; Ganta N, Aknouk M, Nikiforov I,
Bommu VJL, Patel V, Cheriyath P, Hollenbeak C, and Hamza A, designed the research study; Ganta N, Aknouk M,
Alnabwani D, Nikiforov I, Bommu VJL, Patel V, and Hollenbeak C performed the research; Hollenbeak C, Nikiforov
I, and Cheriyath P contributed in statistical analysis; Ganta N, Aknouk M, Alnabwani D, Nikiforov I, Bommu VJL,
Patel V, and Hollenbeak C analyzed the data and wrote the manuscript.
Conflict-of-interest statement: All authors report no relevant conflicts of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by
external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-
NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license
their derivative works on different terms, provided the original work is properly cited and the use is non-
commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Country/Territory of origin: United States
ORCID number: Nagapratap Ganta 0000-0003-1601-2586; Mina Aknouk 0000-0002-9017-747X; Dina Alnabwani 0000-0001-
5254-4964; Ivan Nikiforov 0000-0003-1358-7181; Veera Jayasree Latha Bommu 0000-0002-8442-2838; Vraj Patel 0000-0002-
2394-1001; Pramil Cheriyath 0000-0002-3439-4605; Christopher S Hollenbeak 0000-0002-3362-814X; Alan Hamza 0000-0002-
6356-2209.
S-Editor: Ma YJ
L-Editor: A
P-Editor: Ma YJ
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