Use of health care resources and cost of care for adults with constipation

Safety evaluation of lubiprostone in the treatment of constipation and irritable bowel syndrome

INTRODUCTION

Lubiprostone is approved in the United States for the treatment of chronic idiopathic constipation and constipation predominant irritable bowel syndrome (IBS-C). Lubiprostone causes secretion of fluid and electrolytes in the small bowel, through the activation of chloride channels, and thereby induces laxation and improvement of bowel functions. It is generally considered to be safe and effective. Common side effects of lubiprostone include nausea, diarrhea, abdominal pain and bloating, and the rare side effect dyspnea. Likely mechanisms for these side effects may be related to lubiprostone's primary action on small bowel secretion and the associated intestinal distension, as well as smooth muscle contraction.

AREAS COVERED

This article reviews the pharmacokinetic and safety profile of lubiprostone, with particular relevance to the two FDA-approved dosages.

EXPERT OPINION

Lubiprostone acts topically in the gut lumen and is almost completely metabolized in the gut lumen. Lubiprostone's M3 metabolite can be detected in low concentrations in the serum and may be responsible for some of its side effects. However, the exact mechanisms by which the side effects are produced are currently unknown.

Development and assessment of the constipation-related disability scale

BACKGROUND

Chronic constipation is associated with impaired quality of life and physical discomfort. Although inability to engage in day-to-day activities has been significantly associated with psychological distress, limited research has examined this relationship in constipated samples.

AIM

To develop and validate the Constipation-Related Disability Scale (CRDS), which assesses the extent of disability caused by constipation.

METHODS

A total of 240 constipated participants and 103 healthy controls completed the CRDS. Reliability was measured with Cronbach's coefficient alpha and test-retest reliability was assessed with intraclass correlation coefficients. Convergent, divergent and predictive validity were assessed.

RESULTS

Component and factor analyses were used to derive two factors: Work/Leisure Activities and Activities of Daily Living, as well as a total CRDS score. Good reliability was found, with alphas ≥ 0.87 and intraclass correlation coefficients ≥ 0.85. All scales were negatively correlated with the physical health subscales of the SF-36 (P < 0.001) and were not significantly correlated with the Epworth Sleepiness Scale and Social Desirability Scale, providing support for convergent and divergent validity, respectively. Evidence of predictive validity was supported by associations between the total CRDS with number of physician visits per year (P < 0.01), missed work in the last year (odds ratio [OR = 1.11, 95% confidence interval [CI] = 1.06-1.19, P < 0.001) and ER visits in the last year (OR = 1.08, 95% CI = 1.00-1.16, P < 0.05).

CONCLUSIONS

The Constipation-Related Disability Scale is the first instrument that assesses the impact of constipation on daily activities. There is evidence of strong reliability and validity of the instrument.

Prevalence and pathophysiology of functional constipation among women in Catalonia, Spain

BACKGROUND

Specific treatment of functional bowel disorders requires precise diagnosis. However, prevalence and subtypes of functional constipation among women are not completely understood.

OBJECTIVE

Our aim was to assess the prevalence of functional constipation and investigate the subtypes of dyssynergic defecation and slow transit constipation among Spanish women.

DESIGN

We performed a prospective epidemiological study in healthy young women and retrospective pathophysiological studies in 2 patient cohorts of women with functional constipation according to Rome II criteria.

SETTINGS

Referral centers at Clínica Sagrada Familia, Barcelona, Spain, and Hospital de Mataró, Mataró, Spain.

PATIENTS

The epidemiological study included 600 healthy young women, aged 37.1 (SD, 8.2) years. Patient cohort 1 comprised 172 women with functional constipation without symptoms of pelvic floor dysfunction, ranging in age from 18 to 45 years. Patient cohort 2 comprised 106 women with functional constipation and symptoms of dyssynergic defecation, ranging in age from 45 to 65 years.

MAIN OUTCOME MEASURES

In healthy women, a questionnaire was used to determine rates of functional constipation, dyssynergic defecation, and slow transit constipation. In patients, results of anorectal manometry, EMG, and colonic transit studies were reviewed to assess subtypes of functional constipation; in addition, results of dynamic videoproctography were reviewed in cohort 2 to assess the role of structural pelvic floor disorders.

RESULTS

The prevalence of functional constipation in healthy young women was 28.8%; symptoms of dyssynergic defecation were found in 8.2%, those of isolated slow transit in only 0.17%. In patient cohort 1, a total of 143 patients (83.1%) showed dyssynergic defecation: 117 patients (68.0%) had paradoxical external anal sphincter contraction and 26 (15.1%) had impaired internal anal sphincter relaxation). Slow transit constipation without dyssynergia was observed in 15 (8.7%). Up to 40.2% of patients with dyssynergia also had delayed colonic transit. In the cohort of 106 women with dyssynergic defecation, videoproctography showed impaired puborectal relaxation in 64 patients (60.4%), anterior rectocele in 65 (61.3%), and rectal prolapse in 13 (12.3%).

LIMITATIONS

We could not estimate the prevalence and subtypes of irritable bowel syndrome in the epidemiological study.

CONCLUSIONS

Functional constipation is extremely prevalent among young, healthy, Spanish women, dyssynergic defecation being the most prevalent subtype. Slow transit constipation without dyssynergic defecation is uncommon. Structural pelvic floor disorders are highly prevalent in middle-aged women with dyssynergic defecation.

Lubiprostone for the treatment of adults with constipation and irritable bowel syndrome

Chronic constipation and IBS-C are two of the most common functional bowel disorders encountered by primary care providers and gastroenterologists, affecting up to 27% of the population in Western countries [1-4]. The treatment of these disorders is often empiric and most current therapies are indicated for episodic constipation. Over time, most patients become refractory to one or more laxatives. Lubiprostone (Amitiza) has been approved by the US Food and Drug Administration (FDA) for the treatment of chronic-idiopathic constipation [6]. It is an oral bicyclic fatty acid that selectively activates type 2 chloride channels in the apical membrane of the intestinal epithelial cells, hence stimulating chloride secretion, along with passive secretion of sodium and water, inducing peristalsis and laxation, without stimulating gastrointestinal smooth muscle. Several trials have shown it to be effective in the treatment of chronic idiopathic constipation, and recently also IBS-C. It has little systemic absorption and almost free of any serious adverse effects, however, occasionally can cause nausea. Based on the available evidence, it is reasonable to conclude that lubiprostone should be added to the short list of evidence-based pharmacotherapies for chronic constipation and IBS-C. Given the overlap between chronic constipation and IBS-C, clinicians can consider two strategies when deciding on the initial dose of lubiprostone. Based on current product labeling, it is recommended that 8 μg bid be started in patients with IBS-C whereas 24 μg bid be used in those with chronic constipation. Thus far, lubiprostone offers a novel approach to our therapeutic armamentarium, however, there is a need for more drugs with different mechanisms of action, in order to treat constipation that is often multifunctional.

Longitudinal direct medical costs associated with constipation in women

BACKGROUND

Although direct medical costs for constipation-related medical visits are thought to be high, to date, there have been no studies examining longitudinal resource utilisation in adults with constipation.

AIM

To estimate the incremental direct medical costs associated with constipation in women.

METHODS

This is a nested case-control study. The study population consisted of all mothers of 5718 children in the population-based birth cohort born during 1976-1982 in a community. The cases presented to the medical facilities with constipation. The controls were randomly selected and matched to cases in a 2:1 ratio. Direct medical costs for constipated women and controls were collected for the years 1987-2002.

RESULTS

We identified 168 women with a diagnosis of constipation. The total direct medical costs over the 15-year period for constipated subjects were more than double those of controls [$63 591 (95% CI: 49 786-81 396) vs. $24 529 (95% CI: 20 667-29 260)]. The overall out-patient costs for constipated women were $38 897 (95% CI: 31 381-48 253) compared to $15 110 (95% CI: 12 904-17 781) for controls. The median of annual out-patient visits for constipated women was 0.16 compared to 0.11 for controls.

CONCLUSION

Women with constipation have significantly higher medical care utilisation and expenditures compared with women without constipation.

Overactive bladder drugs and constipation: a meta-analysis of randomized, placebo-controlled trials

BACKGROUND

Anticholinergic drugs are commonly prescribed for symptomatic treatment of overactive bladder (OAB). While recent meta-analyses have characterized the prevalence of dry mouth among patients utilizing OAB medications, prevalence of constipation has not been systematically reviewed.

AIMS

To provide an effect measure for constipation associated with anticholinergic OAB drugs versus placebo.

METHODS

A meta-analysis of trials with darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, and trospium was conducted. All randomized, placebo-controlled studies of anticholinergic OAB drugs published in English language and identified in Medline and Cochrane databases were considered for inclusion in this meta-analysis. Those meeting predetermined design characteristics and having sufficient duration (≥2 weeks) were included. Constipation-related data from all included studies were abstracted.

RESULTS

One hundred two English-language, randomized, placebo-controlled trials were originally identified. Thirty-seven studies were ultimately included in the analysis, involving 19,434 total subjects (12,368 treatment+7,066 placebo patients). The odds ratios for constipation compared with placebo were as follows: overall [odds ratio (OR) 2.18, 95% confidence interval (CI)=1.82-2.60], tolterodine (OR 1.36, 95% CI=1.01-1.85), darifenacin (OR 1.93, 95% CI=1.40-2.66), fesoterodine (OR 2.07, 95% CI=1.28-3.35), oxybutynin (OR 2.34, 95% CI=1.31-4.16), trospium (OR 2.93, 95% CI=2.00-4.28), and solifenacin (OR 3.02, 95% CI=2.37-3.84).

CONCLUSIONS

Our results demonstrate that patients prescribed anticholinergic OAB drugs are significantly more likely to experience constipation. Differences in muscarinic receptor affinities among individual agents may possibly account for the modest variation in constipation rates observed; however, such a determination warrants additional research.

Advances in diagnostic assessment of fecal incontinence and dyssynergic defecation

Disorders of the anorectum and pelvic floor affect approximately 25% of the population. Their evaluation and treatment have been hindered by a lack of understanding of underlying mechanism(s) and a working knowledge of the diagnostic advances in this field. A meticulous evaluation of anorectal structure and its function can provide invaluable insights to the practicing gastroenterologist regarding the pathogenic mechanism(s) of these disorders. Also, significant new knowledge has emerged over the past decade that includes the development of newer diagnostic tools such as high-resolution manometry and magnetic resonance defecography as well as a better delineation of the clinical and pathophysiologic subtypes of constipation and incontinence. This article provides an up-to-date review on the role of diagnostic tests in the evaluation of fecal incontinence and constipation with dyssynergic defecation.

Clinical utility of colonic and anorectal manometry in chronic constipation

Constipation is one of the most common digestive problems in North America with significant psychosocioeconomic implications. It is caused by either a primary disorder of colonic and anorectal function or by many secondary conditions such as constipating drugs, metabolic disorders and other colorectal problems. Given the heterogeneity of problems that cause constipation, defining the underlying pathophysiology is increasingly being recognized as a key step toward optimal management. Colonic manometry with sensation and tone assessment (barostat) and anorectal manometry with rectal sensation and compliance assessment and balloon expulsion test can provide a comprehensive evaluation of colonic and anorectal sensorimotor function and facilitate a diagnosis of slow transit constipation, dyssynergic defecation or irritable bowel syndrome, or an overlap of these disorders. This review provides a critical appraisal of the role of manometric techniques toward augmenting our understanding of colonic and anorectal physiology, both in health and constipation and discussing their clinical utility in the diagnosis and management of chronic constipation.

Update on the management of constipation in the elderly: new treatment options

Constipation disproportionately affects older adults, with a prevalences of 50% in community-dwelling elderly and 74% in nursing-home residents. Loss of mobility, medications, underlying diseases, impaired anorectal sensation, and ignoring calls to defecate are as important as dyssynergic defecation or irritable bowel syndrome in causing constipation. Detailed medical history on medications and co-morbid problems, and meticulous digital rectal examination may help identify causes of constipation. Likewise, blood tests and colonoscopy may identify organic causes such as colon cancer. Physiological tests such as colonic transit study with radio-opaque markers or wireless motility capsule, anorectal manometry, and balloon expulsion tests can identify disorders of colonic and anorectal function. However, in the elderly, there is usually more than one mechanism, requiring an individualized but multifactorial treatment approach. The management of constipation continues to evolve. Although osmotic laxatives such as polyethylene glycol remain mainstay, several new agents that target different mechanisms appear promising such as chloride-channel activator (lubiprostone), guanylate cyclase agonist (linaclotide), 5HT₄ agonist (prucalopride), and peripherally acting μ-opioid receptor antagonists (alvimopan and methylnaltrexone) for opioid-induced constipation. Biofeedback therapy is efficacious for treating dyssynergic defecation and fecal impaction with soiling. However, data on efficacy and safety of drugs in elderly are limited and urgently needed.

Health utilization and cost impact of childhood constipation in the United States

OBJECTIVE

To estimate the total health care utilization and costs for children with constipation in the United States.

STUDY DESIGN

We analyzed data from 2 consecutive years (2003 and 2004) of the Medical Expenditure Panel Survey (MEPS), a nationally representative household survey. We identified children who either had been reported as constipated by their parents or had received a prescription for laxatives in a given year. Outcome measures were service utilization and expenditures.

RESULTS

The MEPS database included a total of 21 778 children age 0 to 18 years, representing 158 million children nationally. An estimated 1.7 million US children (1.1%) reported constipation in the 2-year period. No differences with respect to age, sex, race, and socioeconomic status were found between the children with constipation and those without constipation. The children with constipation used more health services than children without constipation, resulting in significantly higher costs: $3430/year vs $1099/year. This amounts to an additional cost for children with constipation of $3.9 billion/year.

CONCLUSIONS

This study demonstrates that childhood constipation has a significant impact on the use and cost of medical care services. The estimated cost per year is 3 times than that in children without constipation, which likely is an underestimate of the actual burden of childhood constipation.

Constipation: evaluation and treatment of colonic and anorectal motility disorders

This article focuses on the colonic and anorectal motility disturbances that are associated with chronic constipation and their management. Functional chronic constipation consists of three overlapping subtypes: slow transit constipation, dyssynergic defecation, and irritable bowel syndrome with constipation. The Rome criteria may serve as a useful guide for making a clinical diagnosis of functional constipation. Today, an evidence-based approach can be used to treat patients with chronic constipation. The availability of specific drugs for the treatment of chronic constipation, such as tegaserod and lubiprostone, has enhanced the therapeutic armamentarium for managing these patients. Randomized controlled trials have also established the efficacy of biofeedback therapy in the treatment of dyssynergic defecation.

Lubiprostone for constipation and irritable bowel syndrome with constipation

Chronic constipation and irritable bowel syndrome are heterogeneous disorders characterized by altered bowel habits, abdominal discomfort and/or difficult defecation. These conditions have a significant impact on patients' quality of life, as well as on the US economy, both in terms of healthcare costs and lost productivity. Treatment typically begins with lifestyle changes, increased fiber intake and osmotic and stimulant laxative intake. However, treatments for constipation vary in terms of their efficacy and safety. Furthermore, surveys of physicians and patients have revealed a strong desire for improved therapeutic options. Lubiprostone is a synthetic bicyclic fatty acid that is gut selective and stimulates type 2 chloride channels, resulting in increased chloride, sodium and water secretion into the lumen. The increased fluid secretion causes luminal distension, secondary peristalsis and laxation. Randomized Phase III trials have shown that lubiprostone is efficacious in the treatment of chronic idiopathic constipation and irritable bowel syndrome with constipation. The US FDA has approved lubiprostone at a dose of 24 microg twice daily for the treatment of chronic idiopathic constipation in adults, and at a dose of 8 microg twice daily for irritable bowel syndrome with constipation in adult women. Nausea, diarrhea and headaches are the most commonly reported side effects. In long-term studies, lubiprostone appears to be safe.

Dyssynergic defecation and biofeedback therapy

Constipation caused by dyssynergic defecation is common and affects up to one half of patients with this disorder. It is possible to diagnose this problem through history, prospective stool diaries, and anorectal physiologic tests. Randomized controlled trials have now established that biofeedback therapy is not only efficacious but superior to other modalities and that the symptom improvement is caused by a change in underlying pathophysiology. Development of user friendly approaches to biofeedback therapy and use of home biofeedback programs will significantly enhance the adoption of this treatment by gastroenterologists and colorectal surgeons.

Constipation: evaluation and treatment of colonic and anorectal motility disorders

This article focuses on the colonic and anorectal motility disturbances that are associated with chronic constipation and their management. Functional chronic constipation consists of three overlapping subtypes: slow transit constipation, dyssynergic defecation, and irritable bowel syndrome with constipation. The Rome criteria may serve as a useful guide for making a clinical diagnosis of functional constipation. Today, an evidence-based approach can be used to treat patients with chronic constipation. The availability of specific drugs for the treatment of chronic constipation, such as tegaserod and lubiprostone, has enhanced the therapeutic armamentarium for managing these patients. Randomized controlled trials have also established the efficacy of biofeedback therapy in the treatment of dyssynergic defecation.