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Summary

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Background  Constipation is a common, often chronic, gastrointestinal motility disorder characterized by such symptoms as straining, hard stool, and infrequent defecation. Published literature is limited regarding symptom prevalence, healthcare-seeking behaviour, and patient satisfaction with traditional therapies for chronic constipation.

Aim  To assess the prevalence of chronic constipation among a random sample of Americans, to identify the frequency, severity and bothersomeness of their symptoms, and to assess satisfaction levels with traditional treatments.

Methods  All members (N = 37 004) of the Knowledge Networks Panel, representative of the US population, participated in a web-based survey. Eligibility was established using a six-question screener.

Results  Of the 24 090 panellists consenting to participate, 557 met eligibility requirements and took the 45-question survey. The most prevalent symptom was straining (79%). Hard stool and straining were the top two severe symptoms, and bloating, straining and hard stool were the top three bothersome symptoms. Symptoms affected quality of life of more than half (52%) the respondents. Among those who worked or went to school, 12% experienced reduced productivity and a mean of 2.4 days of absence in the month before the survey. Most respondents had used (96%) or were using (72%) constipation relief therapy; however, nearly half (47%) were not completely satisfied, mainly because of efficacy (82%) and safety (16%) concerns.

Conclusions  Chronic constipation is common. Individual symptoms are often severe and bothersome, and many patients are dissatisfied with traditional treatment options, primarily because of lack of efficacy.


Introduction

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Constipation is a prevalent, often chronic, gastrointestinal (GI) motility disorder. It affects from 2% to 27% of North Americans, with most estimates concentrated around 15%,1 and is more common in women than men (estimated prevalence ratio of 2.2:1).1 Rome diagnostic criteria (Rome II,2 Rome III3) for functional constipation were developed to standardize the definition of constipation for enrolment in clinical trials. However, there is no widely accepted, clinically useful definition of constipation. Although doctors often define constipation based on stool frequency,4 patients define constipation as a multisymptom disorder that includes infrequent bowel movements, hard/lumpy stool, straining, bloating, feeling of incomplete evacuation after a bowel movement and abdominal discomfort.5

In addition to the bothersome symptoms associated with this condition, health-related quality of life (QoL) is negatively impacted in people with chronic constipation,6, 7 and studies have shown that the degree of symptom severity of chronic constipation correlates negatively with the patient's perceived QoL.8 Women who seek medical care for constipation often have increased psychological and social morbidities, including anxiety, depression, increased somatization and decreased sexual satisfaction,9 which could contribute to poor QoL. Population studies have shown that in patients with chronic constipation, poor QoL was an important predictor of healthcare utilization and resultant healthcare costs.10, 11 Other studies have shown that patients who seek medical treatment for chronic constipation, estimated at only 25% of those affected, are not always effectively treated and are generally dissatisfied with treatment outcomes.5, 12

The goal of therapy for patients with chronic constipation is not only to provide multisymptom relief, but also to address the underlying pathophysiology. Although lifestyle changes such as increased exercise, dietary fibre and fluid intake are beneficial approaches for some patients with constipation, the true effectiveness of these measures in patients with chronic constipation has not yet been proven.13, 14 Traditional therapies such as fibre or osmotic and stimulant laxatives often have limitations because they generally do not target the multiple symptoms associated with chronic constipation, nor do they address the underlying cause(s). Further, though many of these treatments adequately alleviate one symptom of constipation, they may exacerbate another. For example, fibre improves stool form and frequency but may worsen the symptoms of gas and bloating.14

The published medical literature is limited regarding symptom prevalence, healthcare-seeking behaviour and patient satisfaction with traditional therapies for chronic constipation. Moreover, no direct data have been published on patient perception of treatment outcomes. The purpose of this survey, in the form of a web-based questionnaire, was to evaluate patients who sought care for the symptoms of chronic constipation in the previous year. Specific survey goals included assessment of the prevalence and variety of chronic constipation symptoms; identification of the frequency, severity and bothersomeness of commonly reported constipation symptoms; and determination of patients’ levels of satisfaction with traditional therapies.

Methods

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Panellist recruitment and selection

All members of the Knowledge Networks Panel (N =37 004), which is representative of the total US population and tracks age, race, geographic region, employment status and other demographic elements, were recruited to participate in this web-based survey. Recruitment and interviewing were conducted between 31 March and 23 April 2004. The web-enabled panel was composed of members of households with and without Internet access, and all members were provided the same equipment for participation in Internet surveys. The surveys were self-administered and accessible any time of day for a designated period. Panellists received notice in their password-protected e-mail accounts when assigned surveys were available for completion. Survey responses were confidential, and identifying information was never revealed. Participants had the option to leave the panel at any time.

To ensure that the panel was probability-based representative of the US population, panellists were recruited through random-digit telephone dialling. Panel sample weights were adjusted to US census demographic benchmarks, and the sample design weights were calculated based on specific design parameters. Weighting adjustments were applied to the final survey data to reduce the effects of non-sampling error (variance and bias).

Eligibility

Everyone who agreed to participate in the survey was asked to complete an online, self-administered, six-question screener to evaluate whether they met entry criteria.

Inclusion criteria

Recruits were eligible to participate in this study if they were proficient in the English language, were 18 years of age or older, experienced at least two symptoms of constipation in the year before the survey as defined by Rome II criteria2 (Table 1; the need for manual manoeuvres to facilitate defecation was not used as a criterion for constipation in this survey because of the high degree of patient misinterpretation), sought doctor care for constipation symptoms in the year before the survey, and had not been diagnosed as having irritable bowel syndrome (IBS) or any GI disease of organic cause with associated constipation.

Table 1.   Rome II criteria for functional constipation2 and survey inclusion criteria
Rome II criteriaSurvey inclusion criteria
 The presence of 2 or more of the following for at least 3 months, which need not be consecutive, in the past 12 months:*The presence of 2 or more of the following in the year before the survey:
   Straining in >25% of defecations Straining in >25% of defecations
   Lumpy or hard stool in >25% defecations Lumpy or hard stool in >25% defecations
   Sensation of incomplete evacuation in >25% of defecations Sensation of incomplete evacuation in >25% of defecations
   Sensation of anorectal obstruction/blockade in >25% defecations Sensation of anorectal obstruction/blockade in >25% defecations
   Manual manoeuvres to facilitate >25% defecations (e.g. digital evacuation, support of the pelvic floor) <3 defecations per week
   <3 defecations per weekParticipants with abdominal discomfort who did not have a doctor diagnosis of irritable bowel syndrome or spastic colon were included
* Loose stool is not present, and criteria are insufficient for irritable bowel syndrome 
Exclusion criteria

Recruits were not eligible to participate in the survey if they were pregnant during the survey or had been pregnant in the year before the survey. Patients were specifically asked whether they had been diagnosed by a doctor as having cancer or an organic GI disease [e.g. diverticulitis, diverticulosis, inflammatory bowel disease (IBD), Crohn's disease], IBS with constipation (IBS-C), or spastic or irritable colon. Participants reporting abdominal pain, which is the hallmark symptom of IBS, were not excluded unless they had been diagnosed by a doctor as having IBS-C or spastic or irritable colon. Therefore, some participants with abdominal discomfort/pain were included because they did not have a doctor diagnosis of IBS or spastic colon. Anyone taking tegaserod, which was not approved by the US Food and Drug Administration for chronic idiopathic constipation at the time of the survey, was also excluded.

Survey administration

Panellists meeting entry criteria completed an online, self-administered, 45-question survey. Participants were directed to read and understand an informed consent document, after which they were given the option of continuing with the survey. Panellists were also advised that their participation was voluntary and that they had the option of not answering specific questions.

As part of the survey, participants were asked to report on the presence, duration, frequency, severity, bothersomeness and impact on QoL of a variety of constipation-related symptoms, including straining, hard stool, abdominal discomfort, bloating, infrequent bowel movements and feeling of incomplete evacuation after a bowel movement. They were also asked to report on treatments, treatment satisfaction and optimal product attributes.

Ethical and legal aspects

Surveys were conducted according to the globally accepted standards of good clinical practice (as defined in the ICH E6 Guideline for Good Clinical Practice, 1 May 1996) in agreement with the latest version of the Declaration of Helsinki, in accordance with HIPPA, and in keeping with local regulations. Study protocols and all associated materials were reviewed and approved by a central institutional review board (New England Institutional Review Board).

Statistical analysis

Summary statistics such as mean values, standard deviations, minimums, quartiles, maximums for continuous variables, counts and percentages for categorical variables and confidence intervals (when appropriate) were used. Consistent with the exploratory, hypothesis-generating nature of the study, statistical tests (i.e. χ2-tests for categorical variables and t-tests for continuous variables) were conducted at the nominal 0.05 level, with no attempt to control for multiple testing. Statistical modelling techniques (e.g. regression, anova, survival analysis) were used to characterize the nature and strength of relationships observed between data elements.

Results

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Demographics

Of 37 004 members of the Knowledge Network Panel who were contacted, 27 923 responded to the invitation e-mail, 24 090 consented to continue and 557 were deemed eligible to participate in the survey. More than half (56%) of the 557 eligible participants were women, and most (73%) were between 18 and 64 years of age and were white (82%; Table 2).

Table 2.   Participant demographics
 Number of participantsPercentage
Total557100
Sex
 Male24343.6
 Female31456.4
Age (years)
 18–348715.6
 35–4914726.4
 50–6417130.7
 65+15227.3
Ethnicity
 White non-Hispanic45681.9
 Black468.2
 Hispanic397.0
 Other162.9

Screener results

When screening consenting participants for eligibility, 19% (4680 of 24 090) of the respondents reported experiencing two or more symptoms of constipation per year. Of this percentage, most (n = 4548) were not pregnant or had not been pregnant in the year before the survey. Consistent with published reports,5 only 25% (1147 of 4548) of those meeting inclusion criteria to this point reported seeking care for their constipation symptoms within the year before the survey. Finally, 557 of these 1147 patients had not been diagnosed as having IBS or any GI diseases of organic cause with associated constipation, had at least two symptoms of constipation in the year before the survey, and were not taking tegaserod at the time of the survey.

Survey results

Duration and frequency of symptoms

Of the 557 eligible respondents, 30% (168 of 557) reported having had symptoms of constipation for 1 year or less, 26% (147 of 557) reported having them 2–3 years, 16% (89 of 557) reported having them 4–5 years, 6% (33 of 557) reported having them 6–9 years and 21% (117 of 557) reported having them 10 years or more (Figure 1). The mean number of years respondents had constipation was 4.2. Most (72%) respondents reported having symptoms of constipation between 1 and 6 days a week, and 35% reported having them 2 or 3 days a week. The mean number of days per week respondents had constipation symptoms was 3.2 ± 0.09 days. No differences were observed between men and women.

image

Figure 1.  Number of years respondents (n = 557) experienced constipation.

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Range of symptoms

Respondents reported a wide range of symptoms, and many reported more than one symptom (Figure 2). Most (79%) respondents reported straining, nearly all (90%) of whom had this symptom for more than 6 years. Seventy-one percent of respondents reported hard stool; 84% of them had this symptom for more than 6 years. Other reported symptoms included abdominal discomfort (62%), bloating (57%), infrequent bowel movements (57%) and feeling of incomplete evacuation after a bowel movement (54%). Percentages of respondents who reported having had these symptoms for more than 6 years were 71%, 73%, 67%, and 62%, respectively. Women were more likely than men to report bloating (63% of women vs. 50% of men). Symptom prevalence was higher among those who experienced constipation for a long time (6 or more years) than among those who experienced symptoms for 5 years or less.

image

Figure 2.  Constipation symptoms experienced by respondents (n = 557).

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Symptom severity and bothersomeness

Respondents were asked to rate the severity of constipation as a medical condition and the severity of their individual symptoms using the following descriptors: not at all, not very, somewhat, very and extremely severe. Overall, more than half (54%) of respondents considered constipation an extremely, very or somewhat severe medical condition. In rating the severity of their individual symptoms (respondents could choose more than one symptom), 79% rated straining, 85% rated hard stool, 75% rated infrequent bowel movements, 73% rated bloating, 71% rated abdominal discomfort and 70% rated feeling of incomplete evacuation after a bowel movement as extremely, very or somewhat severe (Figure 3). In general, symptom severity increased with the length of time patients experienced constipation. Again, symptoms were more severe among those who had constipation for a long time (6 or more years) than among those who had it for 5 years or less.

image

Figure 3.  Severity and bothersomeness of individual constipation symptoms.

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Respondents were also asked to rate the degree of bothersomeness of their individual constipation symptoms using the following descriptors: not at all, not very, somewhat, very and extremely bothersome. Most respondents (76%) rated their constipation as extremely, very or somewhat bothersome (Figure 3). For individual symptoms, 86% of respondents rated bloating, 85% rated straining, 85% rated hard consistency of stool, 81% rated abdominal discomfort, 80% rated infrequent bowel movements and 78% rated feeling of incomplete evacuation after a bowel movement as extremely, very or somewhat bothersome. Like symptom prevalence and severity, symptoms were more bothersome among those who experienced constipation for 6 or more years than among those who experienced it for 5 years or less.

Impact on quality of life

More than half (52%) of respondents reported that constipation affected their QoL somewhat, a lot or a great deal (Figure 4). The effect of individual constipation symptoms on participants’ QoL was rated using the following descriptors: not at all, a little, somewhat, a lot and a great deal. Bloating was reported by the largest percentage of respondents (71%) as at least somewhat affecting their QoL. Other symptoms reported to affect patient QoL (a great deal, a lot or somewhat) included abdominal discomfort (65%), infrequent bowel movements (63%), feeling of incomplete evacuation after a bowel movement (63%), hard stool (59%) and straining (59%). In addition, 69% of respondents who worked or went to school reported some degree of work impairment, and 73% of respondents reported social or personal impairment as a result of symptoms of constipation, though most patients did not feel that constipation completely prevented them from working or performing their daily activities. Within the month preceding the survey, 12% of respondents who worked or went to school reported missing time from work or class (mean, 2.4 days) because of constipation symptoms.

image

Figure 4.  Symptoms of constipation affect quality of life.

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Treatments to reduce constipation symptoms

An overwhelming majority (96%) of respondents reported that they had at some time used treatment for their constipation symptoms. Overall, 80% tried over-the-counter (OTC) products, and 35% had tried prescription medication. Most (72%; 385 of 533) respondents reported that they were currently taking medication for their constipation symptoms. Treatments included OTC products [including laxatives (27%) and fibre (50%)] and prescription medications (11%), including prescription laxatives (8% of total medications taken or 91% of total prescription medications).

Treatment satisfaction

Overall, 47% of respondents were not completely satisfied with their current constipation treatment. Most (82%) respondents reported their reason for dissatisfaction was efficacy related, including does not work well (39%), inconsistent results (25%), continuous dosage (7%), still requires laxative use (3%), not fast acting (1%) and does not treat infrequent bowel movements (2%). Other reasons for dissatisfaction included safety and adverse effect concerns (16%), price and cost issues (3%), taste (2%) or inconvenience (1%). Furthermore, 9% of respondents reported missing work or school despite their current therapy.

Those who were taking fibre at the time of the survey (n = 268) were asked to rate their level of satisfaction with this approach. Overall, 80% of these respondents were not completely satisfied with the ability of fibre to relieve their bloating, 79% were not completely satisfied with the predictability of fibre, 66% thought fibre did not completely relieve the multiple symptoms of constipation and 50% thought fibre did not completely relieve their constipation (Figure 5). Furthermore, most (64%) respondents were not completely satisfied with the ability of fibre to improve their QoL.

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Figure 5.  Ratings for traditional constipation treatments.

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Those who were taking OTC laxatives at the time of the survey (n = 146) were asked to rate their attributes. Overall, 71% of respondents were not completely satisfied with the predictability of OTC laxatives, 67% did not think OTC laxatives completely relieved their bloating, 60% did not think OTC laxatives completely relieved the multiple symptoms of constipation and 44% did not think OTC laxatives completely relieved their constipation (Figure 5). Moreover, most (68%) respondents were not completely satisfied with the ability of OTC laxatives to improve their QoL.

Those who were taking prescription laxatives at the time of the survey (n = 42) were asked to rate their level of satisfaction with these products. Overall, 75% of respondents were not completely satisfied with the predictability of prescription laxatives, 52% did not think prescription laxatives were completely effective in relieving their bloating, 50% did not think prescription laxatives were completely effective in relieving their constipation and 50% did not think prescription laxatives were completely effective in relieving the multiple symptoms of constipation (Figure 5). In addition, nearly half (44%) of respondents were not completely satisfied with the ability of prescription laxatives to improve their QoL.

Optimal product attributes

Respondents rated certain key attributes of a medication for constipation as extremely or very important, including effective relief of constipation (straining/hard, infrequent stool; 80%), effective at improving the quality of bowel movements (79%), well tolerated (74%), predictable response time (73%), relief of multiple symptoms (71%), appropriate for long-term use (71%) and effective relief of bloating (64%).

Discussion

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

The findings from this survey are consistent with those reported previously with regard to the high prevalence of constipation, its multifaceted symptoms, its oftentimes bothersome nature that, for many, results in a negative impact on QoL, and the generally low level of satisfaction with the efficacy and tolerability profiles of traditional treatment options.1, 6, 15, 16 Three findings were of particular relevance to the treatment of patients with constipation: (i) the symptom that patients view as most bothersome often correlates directly with the symptom they view as most severe and prevalent; (ii) severity and bothersomeness, and the occurrence of additional symptoms, increase as the duration of symptoms lengthens and (iii) patients are often poorly satisfied with symptom relief achieved with fibre and with OTC and prescription laxatives. The clinical implications of these findings are important to consider.

Although constipation is often regarded simply as infrequency of bowel movements, it is actually a multiple-symptom complex that varies in chronicity and intensity from one patient to another, necessitating an individualized treatment approach. Although participants in this survey met inclusion criteria based on Rome II criteria for functional constipation, among them symptoms associated with constipation, including some not included in the Rome criteria, were reported. This result is consistent with previous reports in which patients with constipation reported a wide variety of symptoms.5 Indeed, in this survey, straining (79%), hard stool (71%), abdominal discomfort (62%), bloating (57%) and feeling of incomplete evacuation after a bowel movement (54%) were reported at frequencies similar to those reported for infrequent bowel movements (57%). The varied manifestations that patients experience often necessitate use of multiple medications targeted at individual symptoms, increasing the potential for adverse effects and drug interactions. Of the many steps involved in evaluating and treating a patient with constipation, elucidating the symptom that the patient views as most bothersome is among the most important in developing a treatment goal and initiating a treatment plan. This survey revealed that patients often rate the severity and bothersomeness of individual symptoms in a rank order similar to that for prevalence. Identifying the key symptom(s) to target (in terms of underlying cause and treatment options) is therefore a critical first step in developing a realistic action plan that attempts to minimize the number of therapeutic agents used.

The pathophysiology of some forms of constipation has been well described, and a number of subtypes, including normal-transit constipation, slow-transit constipation and defecatory disorders, have been characterized based on underlying pathophysiological mechanisms.16, 17 Patients with slow-transit constipation report, among others, symptoms of straining, hard/lumpy stool and infrequent defecation, and they exhibit reduced gut transit when assessed using radio-opaque markers or scintigraphy. Patients with normal-transit constipation also report symptoms of straining, hard/lumpy stool and infrequent defecation; however, they exhibit normal motility upon testing. Treatment for these patient groups is generally pharmacological. Patients with defecatory disorders, who report excessive straining, feelings of incomplete evacuation and manual manoeuvring for a bowel movement, frequently have anorectal obstruction or abnormal coordination of pelvic and abdominal muscles (dyssynergia). Biofeedback therapy or surgery is often recommended. Although each subtype has its own characteristics, significant overlap typically exists among the groups. Determining the presence of these abnormalities requires specific testing, which is usually not undertaken in clinical practice. In this survey, the specific subtype of constipation was not elicited. However, straining was reported as one of the most frequent symptoms of constipation. Excessive straining, feelings of incomplete evacuation, the need to apply perineal or vaginal pressure or the need for direct digital evacuation of stool are all common symptoms observed in patients with defecatory disorders. It is possible that some survey participants had an unrecognized defecatory disorder that contributed to their constipation. Given that patients with defecatory disorders do not respond to fibre and frequently do not improve with OTC laxatives, the inclusion of significant numbers of participants with defecatory disorders could have contributed to the observed lack of efficacy of traditional treatment options. Conversely, the prevalence of a defecatory disorder is considerably less common than normal-transit constipation, in which straining is also a typical symptom. In a population-based survey such as this, the presence of undiagnosed defecatory disorders probably does not contribute significantly to the lack of satisfaction with traditional therapy observed in this study.

For many patients, constipation is a chronic condition. In this survey, almost one quarter (21%) of respondents reported experiencing symptoms for 10 years or more. A notable finding regarding the duration of any symptom was that the severity and bothersomeness, as well as the occurrence of additional symptoms, increased as symptom duration lengthened. This observation may reflect several factors, including development of constipation-associated complications and increasing abnormality over time. The clinical implication of these findings is that patients with chronic symptoms of constipation often require more aggressive therapy, including the use of prescription products.

Constipation imposes a heavy economic burden on patients and society, with sales of laxatives alone accounting for several hundred million dollars each year.16 Despite the common view of constipation as a disorder that can be self-treated with the large armamentarium of OTC treatment options, poorly controlled constipation-related symptoms account for approximately 2.5 million doctor visits per year, with 85% of patients receiving prescriptions during these visits.18 This survey confirmed the fact that many people are disappointed with the efficacy and safety profiles of traditional treatment approaches. Respondents tried a variety of OTC and prescription agents, and only half were satisfied with any particular option. For most, a lack of efficacy was the leading reason for dissatisfaction. Severe slow-transit constipation that is refractory to traditional pharmacological therapies could be one of the reasons for the observed dissatisfaction among patients.16, 17 Regardless, a need clearly exists for effective, well-tolerated treatment options that target multiple symptoms of constipation. When asked what product attributes were most important to them, respondents rated effective relief of constipation symptoms (straining; hard/lumpy, infrequent stool), improvement in quality of bowel movements, tolerability, predictable response time, multisymptom relief, long-term use and efficacy in alleviating bloating as most imperative. Treatments that fulfil at least several of these attributes are likely to play an important role in the treatment of constipation.

Conclusions

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Results of this survey confirm that constipation is a prevalent condition that negatively impacts patients’ daily lives, often necessitating doctor office visits and pharmacological treatment. Proactive elucidation of the symptoms that patients consider most bothersome is an important step in developing a targeted treatment plan. For numerous reasons, patients are often unsatisfied with the symptom relief achieved from traditional treatment approaches, such as bulking agents and laxatives. These findings highlight an important unmet need for treatment options that target the multiple symptoms of constipation. Fortunately, the armamentarium of effective, well-tolerated therapeutic options is expanding. New and emerging treatments for constipation are likely to fill an important void for many patients, particularly those who experience symptoms on a chronic basis and who may require a more aggressive treatment approach.

Acknowledgements

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Authors' declaration of personal interests: Dr Johanson is a consultant for Boehringer Ingelheim, Microbia, Prometheus, Sucampo, Takeda and Theravance and a member of the speakers bureaus for Novartis, Sucampo and Takeda. Jeffrey Kralstein is an employee of Novartis Pharmaceuticals Corporation.

Declaration of funding interests: this study was funded in full by Novartis. The writing of this paper was funded in part by Novartis. Initial data analyses were undertaken by Knowledge Networks and received funding from Novartis. Writing support was provided by Cathy R. Winter, PhD, and Maribeth Bogush, PhD, and funded by Novartis.

References

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References
  • 1
    Higgins PD, Johanson JF. Epidemiology of constipation in North America: a systematic review. Am J Gastroenterol 2004; 99: 7509.
    Direct Link:
  • 2
    Thompson WG, Longstreth GF, Drossman DA, Heaton KW, Irvine EJ, Muller-Lissner SA. Functional bowel disorders and functional abdominal pain. Gut 1999; 45 (Suppl. II): II437.
  • 3
    Longstreth GF, Thompson WG, Chey WD, Houghton LA, Mearin F, Spiller RC. Functional bowel disorders. Gastroenterology 2006; 130: 148091.
  • 4
    Herz MJ, Kahan E, Zalevski S, Aframian R, Kuznitz D, Reichman S. Constipation: a different entity for patients and doctors. Fam Pract 1996; 13: 1569.
  • 5
    Pare P, Ferrazzi S, Thompson WG, Irvine EJ, Rance L. An epidemiological survey of constipation in Canada: definitions, rates, demographics, and predictors of health care seeking. Am J Gastroenterol 2001; 96: 31307.
    Direct Link:
  • 6
    O'Keefe EA, Talley NJ, Zinsmeister AR, Jacobsen SJ. Bowel disorders impair functional status and quality of life in the elderly: a population-based study. J Gerontol A Biol Sci Med Sci 1995; 50: M1849.
  • 7
    Chang L. Review article: Epidemiology and quality of life in functional gastrointestinal disorders. Aliment Pharmacol Ther 2004; 20 (Suppl. 7): 319.
  • 8
    Glia A, Lindberg G. Quality of life in patients with different types of functional constipation. Scand J Gastroenterol 1997; 32: 10839.
  • 9
    Mason HJ, Serrano-Ikkos E, Kamm MA. Psychological morbidity in women with idiopathic constipation. Am J Gastroenterol 2000; 95: 28527.
    Direct Link:
  • 10
    Irvine EJ, Ferrazzi S, Pare P, Thompson WG, Rance L. Health-related quality of life in functional GI disorders: focus on constipation and resource utilization. Am J Gastroenterol 2002; 97: 198693.
    Direct Link:
  • 11
    Koloski NA, Talley NJ, Boyce PM. The impact of functional gastrointestinal disorders on quality of life. Am J Gastroenterol 2000; 95: 6771.
    Direct Link:
  • 12
    Palsson OS, Whitehead WE, Levy R, Feld A, Von Korff M, Turner M. Constipation is less effectively treated than other functional bowel problems in a health maintenance organization (HMO). Am J Gastroenterol 2004; 99 (Suppl. 10): 287, abstract 878.
  • 13
    Dosh SA. Evaluation and treatment of constipation. J Fam Pract 2002; 51: 5559.
  • 14
    Doughty DB. When fiber is not enough: current thinking on constipation management. Ostomy Wound Manage 2002; 48: 3041.
  • 15
    Ferrazzi S, Thompson GW, Irvine EJ, Pare P, Rance L. Diagnosis of constipation in family practice. Can J Gastroenterol 2002; 16: 15964.
  • 16
    Lembo A, Camilleri M. Chronic constipation. N Engl J Med 2003; 349: 13608.
  • 17
    Locke GR III, Pemberton JH, Phillips SF. AGA technical review on constipation. Gastroenterology 2000; 119: 176678.
  • 18
    Sonnenberg A, Koch TR. Physician visits in the United States for constipation: 1958 to 1986. Dig Dis Sci 1989; 34: 60611.