Constipation Predominant Irritable Bowel Syndrome and Functional Constipation Are Not Discrete Disorders: A Machine Learning Approach.

INTRODUCTION: Chronic constipation is classified into 2 main syndromes, irritable bowel syndrome with constipation (IBS-C) and functional constipation (FC), on the assumption that they differ along multiple clinical characteristics and are plausibly of distinct pathophysiology. Our aim was to test this assumption by applying machine learning to a large prospective cohort of comprehensively phenotyped patients with constipation. METHODS: Demographics, validated symptom and quality of life questionnaires, clinical examination findings, stool transit, and diagnosis were collected in 768 patients with chronic constipation from a tertiary center. We used machine learning to compare the accuracy of diagnostic models for IBS-C and FC based on single differentiating features such as abdominal pain (a "unisymptomatic" model) vs multiple features encompassing a range of symptoms, examination findings and investigations (a "syndromic" model) to assess the grounds for the syndromic segregation of IBS-C and FC in a statistically formalized way. RESULTS: Unisymptomatic models of abdominal pain distinguished between IBS-C and FC cohorts near perfectly (area under the curve 0.97). Syndromic models did not significantly increase diagnostic accuracy (P > 0.15). Furthermore, syndromic models from which abdominal pain was omitted performed at chance-level (area under the curve 0.56). Statistical clustering of clinical characteristics showed no structure relatable to diagnosis, but a syndromic segregation of 18 features differentiating patients by impact of constipation on daily life. DISCUSSION: IBS-C and FC differ only about the presence of abdominal pain, arguably a self-fulfilling difference given that abdominal pain inherently distinguishes the 2 in current diagnostic criteria. This suggests that they are not distinct syndromes but a single syndrome varying along one clinical dimension. An alternative syndromic segregation is identified, which needs evaluation in community-based cohorts. These results have implications for patient recruitment into clinical trials, future disease classifications, and management guidelines.

Clinical and investigative assessment of constipation: a study from a referral center in western India.

INTRODUCTION: Constipation may be primary or secondary. Pathophysiologic subtypes of primary constipation are dyssynergic defecation (DD), slow (STC), and normal transit constipation (NTC). Clinical subtypes are functional constipation (FC) and constipation predominant IBS (C-IBS). AIMS: The objectives of this paper are to study the clinical profile, categorize and compare various subtypes of primary constipation, and to assess the success of biofeedback therapy (BFT) in a non-randomized, uncontrolled open-label study among patients with DD. MATERIAL AND METHODS: Consecutive constipation patients (April 2011 to December 2012) were evaluated. Patients <18 years and secondary constipation were excluded. FC and C-IBS were classified by Rome III module. All patients, after excluding secondary constipation, underwent anorectal manometry (ARM) with balloon expulsion test and colon transit study (CTS). Patients with DD were given BFT. RESULTS: Out of 128 patients, 23 %, 58 %, and 19 % had secondary constipation, FC, and C-IBS, respectively. Ninety-nine patients had primary constipation. Among those with primary constipation mean age was 53.5 (21-86) years, (77 % males). Forty-six, 15, and 40 had NTC, STC, and DD, respectively. Out of those with DD, 34 had paradoxical anal contraction and 6 had impaired rectal propulsion. FC and C-IBS were clinically and pathophysiologically similar except for abdominal pain. Patients with DD were more likely to have history of finger evacuation, straining, incomplete evacuation, sensation of anorectal obstruction than no DD. Sixty-nine percent of the patients with STC had ≤3 stools/week compared to 37 % with NTC (p-value 0.018). Thirty out of 40 (75 %) patients with DD underwent BFT but 20 completed ≥4 sessions. Seventy percent with ≥4 sessions had improved complete spontaneous bowel movements (CSBM). CONCLUSION: NTC was the most common subtype of primary constipation. Symptoms of finger evacuation, sensation of anorectal obstruction, incomplete evacuation, and straining were more prevalent in DD. ARM and CTS could easily identify patients with DD and STC.

Chronic constipation: overview and challenges.

Despite its high prevalence and cost implications, our understanding of the pathophysiology of constipation remains primitive, and available therapies have limited efficacy. The purpose of this supplement is to address critically the reasons for the current lack of understanding and to propose avenues of future research to address these deficiencies.

Epidemiology of constipation (EPOC) study in the United States: relation of clinical subtypes to sociodemographic features.

OBJECTIVE: Constipation is a common heterogeneous condition, possibly encompassing different clinical subtypes. Little is known about the comparative epidemiology of constipation subtypes. This study was conducted to estimate the prevalence of constipation subtypes and determine whether subtypes differ by sociodemographic factors. METHODS: Between June and September 1997, a telephone interview was conducted with individuals about their bowel habits in the preceding 3 months. Survey data on 15 constipation-related symptoms were used to identify individuals who met prespecified symptom criteria for the following mutually exclusive subgroups: functional constipation, irritable bowel syndrome (IBS), outlet obstruction or delay (outlet), both IBS and outlet (IBS-outlet), and frequent laxative users (i.e., at least every other day). A total of 10,018 eligible individuals in the United States 18 yr of age or older completed the interview. Test-retest reliability of reporting symptoms was assessed in a separate national survey. The Spearman's correlation coefficient for reporting symptoms ranged from 0.54 to 0.83; all but three symptoms had correlations above 0.68. RESULTS: The overall prevalence of constipation was 14.7%. By subtype, prevalence was 4.6% for functional, 2.1% for IBS, 4.6% for outlet, and 3.4% for IBS-outlet. An additional 1.8% of respondents reported laxative use at least every other day. Outlet was the most common subtype among women, whereas functional constipation was the most common subtype among men. The gender ratio varied by subtype, with elevated ratios for outlet (F/M = 1.65) and IBS-outlet (F/M = 2.27) subtypes. The age pattern differed among each of the four subtypes. Prevalence of functional subtype decreased with increasing age. In contrast, outlet subtype did not seem to vary by age, and IBS (both men and women) and IBS-outlet (women only) subtypes increased to age 35 yr and declined thereafter. Prevalence of functional constipation increased with increasing education. Outlet type was more common in nonwhites compared to whites. Finally, 45% of individuals with constipation reported having the condition for 5 yr or more. CONCLUSIONS: Constipation is a heterogeneous condition. Differences in epidemiological profile by age, sex ratio, and relation to other sociodemographical factors support the distinction of two and possibly more symptom-based subtypes.