Safety, efficacy and costs of pharmacotherapy for functional gastrointestinal disorders: the case of alosetron and its implications.
BACKGROUND
Functional gastrointestinal disorders cause substantial morbidity, but not mortality. Alosetron may achieve 'adequate relief ' in diarrhoea-predominant irritable bowel syndrome, but may cause major complications, including death.


OBJECTIVE
To appraise, quantitatively, the trade-off between possible symptomatic improvement and serious complications in the treatment of functional gastrointestinal disorders.


METHODS
A decision analytical model was used to examine alosetron or standard treatment for 6 months in 45-year-old women with diarrhoea-predominant irritable bowel syndrome using the health care system's perspective.


RESULTS
Assuming a 14% higher 'adequate relief' rate with alosetron compared to standard care, and a complication rate of four per 1000 persons in 6 months, alosetron gained 0.00081 quality-adjusted life-years (QALYs) per patient at a cost of 358,700 US dollars per QALY gained. Alosetron gained QALYs if 'adequate relief' increased the patients' utility by more than 0.01 in the base case. In probabilistic analysis, alosetron gained QALYs in 98.2% of iterations at a median cost of 212,600 US dollars per QALY (interquartile range, 138,000-338,900 US dollars per QALY). Results were highly sensitive to the utility gain with 'adequate relief' and alosetron's response and complication rates.


CONCLUSIONS
Alosetron's benefit-to-risk profile appears to be favourable, but its cost per QALY gained may be substantial. Decision analyses on treatments for functional gastrointestinal disorders are likely to be highly sensitive to the utility estimates used. There is a pressing need for direct utility measurements in functional gastrointestinal disorders.
Ladabaum
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Division of Gastroenterology, Department of Medicine, University of California, San Francisco, CA 94143-0538, USA. ladabau@itsa.ucsf.edu
D002243:Carbolines / Q000008:administration & dosage* / Q000009:adverse effects / Q000191:economics; D003109:Colonic Diseases, Functional / Q000188:drug therapy* / Q000191:economics; D003362:Cost-Benefit Analysis; D003967:Diarrhea / Q000188:drug therapy / Q000191:economics; D005260:Female; D005765:Gastrointestinal Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000191:economics; D006801:Humans; D008875:Middle Aged; D019057:Quality-Adjusted Life Years; D012307:Risk Factors; D012449:Safety
D002243:Carbolines; D005765:Gastrointestinal Agents; C090840:alosetron