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Constipation in Adults

General Information


  • constipation defined as unsatisfactory defecation characterized by infrequent stools, difficult stool passage, or both5
  • Rome III criteria defines functional constipation with1,2,5
    • ≥ 2 of the following
      • straining during ≥ 25% of defecations
      • lumpy or hard stools during ≥ 25% of defecations
      • feeling of incomplete evacuation during ≥ 25% of defecations
      • feeling of anorectal obstruction or blockage during ≥ 25% of defecations
      • manually facilitating defecation during ≥ 25% of defecations
      • < 3 unassisted bowel movements/week
    • loose stools rarely present without laxatives
    • criteria for irritable bowel syndrome not sufficiently met (although abdominal pain and/or bloating may be present, they are not predominant symptoms)
    • symptoms present for past 3 months with symptom onset ≥ 6 months before diagnosis
  • functional constipation (chronic idiopathic constipation) often overlaps with Irritable bowel syndrome (IBS)5


  • primary (or idiopathic) constipation has 3 common subtypes1,2
    • most patients in clinical practice will have combination of symptoms from > 1 common subtype, and/or attributable to constipation-predominant irritable bowel disease
    • 3 most common subtypes
      • functional
        • includes chronic idiopathic constipation and constipation-predominant irritable bowel syndrome
        • associated with difficult or delayed evacuation, hard stools, abdominal bloating or discomfort
      • slow transit (or delayed transit) - associated with prolonged time between bowel movements, lack of urge to defecate, abdominal distention, bloating, and discomfort
      • outlet dysfunction (or defecatory disorder) - associated with excessive straining and feeling of incomplete evacuation due to mechanical causes such as Hirschsprung disease, anal stricture, cancer, prolapse, rectoceles, or pelvic floor dysfunction
  • secondary constipation can be due to diet, lifestyle, pregnancy, advanced age, medications or underlying medical conditions (see Causes section for partial list)1


General references used

  1. Foxx-Orenstein AE, McNally MA, Odunsi ST. Update on constipation: one treatment does not fit all. Cleve Clin J Med. 2008 Nov;75(11):813-24
  2. Paquette IM, Varma M, Ternent C, Melton-Meaux G, Rafferty JF, Feingold D, Steele SR. The American Society of Colon and Rectal Surgeons' Clinical Practice Guideline for the Evaluation and Management of Constipation. Dis Colon Rectum. 2016 Jun;59(6):479-92
  3. Pare P, Bridges R, Champion MC, et al. Recommendations on chronic constipation (including constipation associated with irritable bowel syndrome) treatment. Can J Gastroenterol. 2007 Apr;21 Suppl B:3B-22Bfull-text
  4. Bove A, Bellini M, Battaglia E, et al. Consensus statement AIGO/SICCR diagnosis and treatment of chronic constipation and obstructed defecation (part II: treatment). World J Gastroenterol. 2012 Sep 28;18(36):4994-5013full-text
  5. Ford AC, Moayyedi P, Lacy BE, et al; Task Force on the Management of Functional Bowel Disorders. American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation. Am J Gastroenterol. 2014 Aug;109 Suppl 1:S2-26PDF

Recommendation grading systems used

  • Italian Association of Hospital Gastroenterologists and Italian Society of Colo-Rectal Surgery (AIGO/SICCR) recommendation grading system
    • grades of recommendation
      • Grade A - recommendation supported by ≥ 2 Level I trials, without conflicting evidence from other Level I trials
      • Grade B - recommendation based on evidence from a single Level I trial OR evidence from ≥ 2 Level l trials with conflicting evidence from another Level I trial OR evidence from ≥ 2 Level II trials
      • Grade C - recommendations based on levels of evidence III - V
    • levels of evidence
      • Level I - randomized clinical trials with P < 0.05, adequate sample size, and appropriate methodology
      • Level II - randomised clinical trials with P < 0.05, inadequate sample size, and/or inappropriate methodology
      • Level III - non-randomized trials with simultaneous controls
      • Level IV - non-randomized trials with historical controls
      • Level V - case series
    • Reference - AIGO/SICCR consensus statement on diagnosis and treatment of chronic constipation and obstructed defecation (23049207World J Gastroenterol 2012 Sep 28;18(36):4994full-text)
  • American College of Gastroenterology (ACG) 2014 guidelines use Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system
    • strength of recommendation
      • Strong recommendation - desirable effects of an intervention clearly outweigh the undesirable effects
      • Conditional (weak) recommendation - uncertainty about trade-offs between desirable and undesirable effects of an intervention
    • quality of evidence
      • High-quality evidence - further research unlikely to change confidence in estimate of effect
      • Moderate-quality evidence - further research likely to have impact on confidence in estimate of effect
      • Low-quality evidence - further research very likely to have important impact on confidence in estimate of effect and is likely to change estimate
      • Very low-quality evidence - estimate of effect very uncertain
    • Reference - ACG monograph on management of irritable bowel syndrome and chronic idiopathic constipation (25091148Am J Gastroenterol 2014 Aug;109 Suppl 1:S2)
  • American Society of Colon and Rectal Surgeons (ASCRS) grading system for recommendations
    • strength of recommendation grades
      • Grade 1 - strong recommendation - benefits clearly outweigh risks and burdens (or vice versa) for most, if not all, patients
      • Grade 2 - weak recommendation - benefits and risks closely balanced and/or uncertain
    • quality of evidence grades
      • Level A - high-quality evidence - randomized trials without factors that reduce quality of evidence, or well-done observational studies with very large magnitude of effect
      • Level B - moderate-quality evidence - downgraded randomized trials or upgraded observational studies
      • Level C - low- or very low-quality evidence - observational studies or case series
  • Canadian Association of Gastroenterology (CAG) levels of recommendation
    • Level A
      • for interventions, meta-analysis of randomized controlled trials (RCTs) or RCTs with no important flaws, consistent results, and direct or strong indirect evidence
      • for diagnosis and prognosis, meta-analysis of randomized controlled trials (RCTs) or RCTs with no important flaws, consistent results, and direct or strong indirect evidence
    • Level B
      • for interventions
        • meta-analysis of RCTs or RCTs with important flaw OR inconsistent results OR weak indirect evidence
        • nonrandomized studies with no important flaws, consistent results, and direct or strong indirect evidence
      • for diagnosis and prognosis, nonrandomized studies with important flaw OR inconsistent results OR weak indirect evidence
    • Level C
      • for interventions, nonrandomized studies with important flaw OR inconsistent results OR weak indirect evidence
      • meta-analyses or RCTs with combination of important flaws AND inconsistent results AND/OR indirect evidence
    • Level D - other nonexpert opinion evidence
    • Level E - expert opinion
    • Reference - 17464377Can J Gastroenterol 2007 Apr;21 Suppl B:3Bfull-text

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Choosing Wisely Canada acknowledges dissemination of their recommendations through DynaMed Plus to reach the point of clinical decision-making.
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How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T116186, Constipation in Adults; [updated 2018 Dec 03, cited place cited date here]. Available from Registration and login required.

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