Open Access Open Badges Research article

The Zelnorm epidemiologic study (ZEST): a cohort study evaluating incidence of abdominal and pelvic surgery related to tegaserod treatment

John D Seeger12389*, Sherry Quinn3, David L Earnest4, Anthony Lembo5, Braden Kuo6, Elena Rivero7 and Alexander M Walker28

Author affiliations

1 Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, USA

2 Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA

3 OptumInsight, Waltham, MA, USA

4 Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA

5 Beth Israel Medical Center, Boston, MA, USA

6 Gastrointestinal Unit, Massachusetts General Hospital, Boston, MA, USA

7 Novartis Farmaceutica, Barcelona, Spain

8 World Health Information Science Consultants (WHISCON), Newton, MA, USA

9 1620 Tremont St, Suite 3300, Boston, MA, 02120, USA

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Citation and License

BMC Gastroenterology 2012, 12:171  doi:10.1186/1471-230X-12-171

Published: 30 November 2012



Pre-marketing clinical studies of tegaserod suggested an increased risk of abdominal surgery, particularly cholecystectomy. We sought to quantify the association between tegaserod use and the occurrence of abdominal or pelvic surgery, including cholecystectomy.


This cohort study was conducted within an insured population. Tegaserod initiators and similar persons who did not initiate tegaserod were followed for up to six months for the occurrence of abdominal or pelvic surgery. Surgical procedures were identified from health insurance claims validated by review of medical records. The incidence of confirmed outcomes was compared using both as-matched and as-treated analyses.


Among 2,762 tegaserod initiators, there were 94 abdominal or pelvic surgeries (36 gallbladder): among 2,762 comparators there were 134 abdominal or pelvic surgeries (37 gallbladder) (hazard ratio HR] = 0.70, 95% confidence interval [C.I.] = 0.54-0.91 overall, HR = 0.98, 95% C.I. = 0.62-1.55 for gallbladder). Current tegaserod exposure compared to nonexposure was associated with a rate ratio [RR] of 0.68 (95% C.I. = 0.48-0.95) overall, while the RR was 0.99 (95% C.I. = 0.56-1.77) for gallbladder surgery.


In this study, tegaserod use was not found to increase the risk of abdominal or pelvic surgery nor the specific subset of gallbladder surgery.

Abdominal surgery; Tegaserod; Cohort study