Risk Factors Associated with Inadequate Bowel Preparation in Patients with Functional Constipation

  • Xiaoyang Guo
  • Xin Shi
  • Xiaoyu Kang
  • Hui Luo
  • Xiangping Wang
  • Hui Jia
  • Qin Tao
  • Jingjie Wang
  • Mingxin Zhang
  • Jinhai Wang
  • Xiaolan Lu
  • Shiyang Ma
  • Tao Lin
  • Yujie Jing
  • Yanglin PanEmail author
  • Xuegang Guo
  • Daiming Fan
Original Article



Constipation is a common reason of poor bowel preparation, which negatively influences the quality of colonoscopy. Risk factors for inadequate bowel preparation in constipated patients remain unclear.


This study aimed to investigate the high-risk factors that might influence the quality of bowel preparation in patients with functional constipation.


Consecutive patients with functional constipation who underwent colonoscopy between June 2016 and April 2017 were enrolled. A standard split dose of 4 l polyethylene glycol was used for bowel preparation. Patient- and procedure-related parameters were recorded. The primary outcome was an adequate rate of bowel preparation. Risk factors for inadequate bowel preparation were screened by multivariate logistic regression analysis.


A total of 199 patients were included. Adequate bowel preparation was found in 62.8% (125/199) of patients. At multivariate analysis, Bristol stool form scale (BSFS) 1 [odds ratio (OR) 2.73, 95% confidence interval (CI) 1.26–5.90; P = 0.011], rectal pain score during defecation < 2 (OR 4.14, 95% CI 1.22–13.97; P = 0.022), and starting-to-defecation interval ≥ 4 h (OR 3.83, 95% CI 1.34–10.91; P = 0.012) were risk factors for inadequate bowel preparation in patients with constipation. For patients with no, 1, 2, or 3 risk factors, the rates of inadequate bowel preparation were 11%, 23%, 49%, and 65%, respectively.


With the standard preparation regime, > 1/3 of patients with functional constipation had inadequate bowel cleansing. BSFS 1, rectal pain score during defecation < 2, and starting-to-defecation interval ≥ 4 h were identified as independent risk factors for inadequate bowel preparation in constipated patients.

Trial Registration number NCT02842411.


Risk factor Bowel preparation Functional constipation Colonoscopy 



Bowel preparation


Polyethylene glycol


Bristol stool form scale


Boston bowel preparation scale


Patient assessment of constipation symptom


Body mass index


Standard deviation


Odds ratio


Confidence interval



This work was supported in part by the National Natural Science Foundation of China (81370585) and National Key Technology R&D Program (2015BAI13B07).

Author’s contribution

Study concept and design: YP, XG; acquisition of data: XG, HL, XW; MZ, SM, YJ, QT; analysis and interpretation of data: XG; drafting and editing of the manuscript: XS, YP; critical revision of the manuscript for important intellectual content: XG; statistical analysis: XG, XS, XK; administrative and material support: DF.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no competing interests.

Ethics approval and consent to participate

The study protocol and informed consent form were approved by the ethics committees of all participating institutions. Written informed consent was obtained from all the patients.

Consent for publication

Not applicable.


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Xiaoyang Guo
    • 1
    • 2
  • Xin Shi
    • 1
  • Xiaoyu Kang
    • 1
    • 3
  • Hui Luo
    • 1
  • Xiangping Wang
    • 1
  • Hui Jia
    • 1
  • Qin Tao
    • 1
  • Jingjie Wang
    • 3
  • Mingxin Zhang
    • 4
  • Jinhai Wang
    • 5
  • Xiaolan Lu
    • 5
  • Shiyang Ma
    • 5
  • Tao Lin
    • 6
  • Yujie Jing
    • 6
  • Yanglin Pan
    • 1
    Email author
  • Xuegang Guo
    • 1
  • Daiming Fan
    • 1
  1. 1.State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive DiseasesFourth Military Medical UniversityXi’anChina
  2. 2.Department of UltrasoundThe 305 Hospital of PLABeijingChina
  3. 3.Department of Gastroenterology, Tangdu HospitalFourth Military Medical UniversityXi’anChina
  4. 4.Department of GastroenterologyThe First Affiliated Hospital of Xi’an Medical UniversityXi’anChina
  5. 5.Department of GastroenterologyThe Second Affiliated Hospital of Xi’an Jiaotong UniversityXi’anChina
  6. 6.Department of GastroenterologyThe 451 Hospital of PLAXi’anChina

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