An approach to the design of therapeutic trials in IBS

Health-related quality of life among persons with irritable bowel syndrome: a systematic review

AIM

To perform a systematic review of the literature with three objectives: (1) to compare the health related quality of life (HRQoL) of patients with irritable bowel syndrome with that of healthy controls; (2) to compare the HRQoL of irritable bowel syndrome patients to those with other diseases; and (3) to examine therapy-associated changes in HRQoL of irritable bowel syndrome patients.

METHODS

Searches of all English and non-English articles from 1980 to 2001 were performed in Medline and Embase, and two investigators performed independent data abstraction.

RESULTS

Seventeen articles met our selection criteria. 13 studies addressed objective no. 1; 11 showed a significant reduction in HRQoL among irritable bowel syndrome patients. Of these, only one study was considered of high quality. Four studies addressed objective no. 2, none of which was considered to be high quality in addressing this objective. Four trials (three of high quality) addressed objective no. 3. One showed that symptomatic improvement with Leupron compared to placebo was accompanied an improvement only in the comparative health domain of the HRQoL. The second study reported significant positive changes in HRQoL after 12 weeks of cognitive behavioural therapy. The third report of two placebo-controlled studies indicated significant improvement with alosetron on most domains of Irritable Bowel Syndrome Quality of Life Questionnaire.

CONCLUSIONS

(i) There is reasonable evidence for a decrease in HRQoL in patients with moderate to severe irritable bowel syndrome; however, the data are conflicting regarding the impact of irritable bowel syndrome on HRQoL in population-based studies of nonconsulters. (ii) HRQoL in irritable bowel syndrome patients is impaired to a degree comparable to other chronic disorders such as GERD and depression. (iii) A therapeutic response in irritable bowel syndrome-related pain has a corresponding improvement in HRQoL. (iv) Limitations of the literature include focusing on moderate-severe irritable bowel syndrome in referral centres, and lack of appropriate controls

A double-blind, randomized, placebo-controlled dose-ranging study to evaluate the efficacy of alosetron in the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome is a common gastrointestinal disorder characterized by abdominal pain and discomfort and altered bowel habit. Antagonism at the 5-HT3 receptor may be of benefit in the treatment of irritable bowel syndrome.

AIMS

To evaluate the effect of 12 weeks of treatment with alosetron, a 5-HT3 receptor antagonist at doses of 0.1 mg b.d., 0.5 mg b.d. and 2 mg b.d. in irritable bowel syndrome patients.

METHODS

A double-blind, placebo-controlled, parallel-group study with a 2-week screening and a 12-week treatment period was conducted. A total of 462 patients (335 female) recorded details of the severity of their abdominal pain, and bowel function daily on a diary card throughout the study. At monthly clinic visits patients recorded the severity of their abdominal pain/discomfort and diarrhoea on a visual analogue scale.

RESULTS

In the total population and in the female subpopulation (but not in males) alosetron 2 mg b.d. significantly increased the proportion of pain-free days and decreased the visual analogue scale score for diarrhoea compared with placebo. Alosetron at doses of 0.5 mg b.d. and 2 mg b.d. led to a significant hardening of stool, and a reduction in stool frequency in the total population.

CONCLUSION

Alosetron at a dose of 2 mg b.d. is an effective treatment for female patients with irritable bowel syndrome.

Inclusion and exclusion criteria of importance in irritable bowel syndrome trials

Although numerous diseases may mimic or be confused with irritable bowel syndrome (IBS), a detailed and precise clinical history and a normal clinical examination usually lead to an accurate diagnosis of IBS. The presence of symptom criteria and the absence of warning signs must be established. Before entering a clinical trial, several routine tests are generally required: total blood count, erythrocyte sedimentation rate, biochemistry screen, stool culture and examination for occult blood, ova, and parasites, and a recent (<2 years) normal flexible sigmoidoscopy or colonoscopy with biopsy. Blood and stool tests are not necessary for the diagnosis of IBS but are important in the framework of controlled trials. Esophagogastroduodenoscopy, abdominal ultrasonography, and malabsorption tests are needed only in patients with atypical IBS or for phase II trials in certain subgroups of patients. Chronic diseases, drugs, and toxic agents that may mimic IBS symptoms or exacerbate the disorder must be excluded. Errors in patient inclusion will be minimized if the duration and severity of IBS symptoms before inclusion is sufficient and will have little effect on the result of the trial if the new drug is really effective and the study well randomized with a correct calculation of sample size.

Symptom relief with amitriptyline in the irritable bowel syndrome

Anti-depressants have been reported to be useful in the management of the Irritable Bowel syndrome. We studied the efficacy of amitriptyline for 12 weeks in a randomized double-blind placebo-controlled trial. Forty patients who met predefined criteria entered the trial. They received 25 mg amitriptyline for the first week, 50 mg for the second week and 75 mg nightly thereafter until the end of the 12th week. The drug and placebo groups were comparable in all major pretreatment variables. Amitriptyline was found to be significantly more effective than placebo in producing global improvement, increasing feelings of well-being, reducing abdominal pain and increasing satisfaction with bowel movements. Younger age and increasing extroversion predicted a better response to amitriptyline. Severity of depressive and anxiety symptoms and other personality variables did not influence outcome.