Shrividya Iyer, PhD
Associate director of global health outcomes assessment at Wyeth Research
Keith L. Davis, MA
Senior director of health economics at RTI Health Solutions
Sean Candrilli, PhD
Head of health economics at RTI Health Solutions


Purpose: The main objective of this study was to compare the opioid use patterns, resource utilization, and costs of patients on opioid therapy who have constipation with those who do not.

Design: Retrospective, observational matched cohort design

Methodology: Patients initiating opioid therapy between Jan. 1, 1999 and Dec. 31, 2005 were identified from a longitudinal insurance claims database. Patients had ≥30 days of opioid use and continuous plan coverage for ≥6 months before and ≥12 months after their index date, defined as the date of the first pharmacy claim for an opioid.

Constipation was defined as having one or more ICD-9 codes of 564.0 during the follow-up period.

Patterns of opioid use and resource utilization were compared between patients with constipation and a demographically matched (1:1) cohort of opioid initiators without constipation using t-tests and Chi-square (∋2) tests.

Principal findings: We identified 39,485 patients, of whom 2,519 (6.4%) had constipation. Most patients with constipation were female (66%) and ≥45 years old (68%). Compared to controls, the constipation group had significantly higher rates of concurrent use of ≥2 opioids (p<0.0001), discontinuation, and switching between opioids. Patients with constipation had statistically significant higher hospital admissions, emergency room visits, home health services, nursing home care, physician office visits, other outpatient/ancillary care, and laboratory tests. Patients with constipation had significantly higher mean all-cause costs for emergency, physician visits, nursing facility, home health, and prescription drug services compared to patients without constipation.

Conclusion: Opioid-treated patients with constipation were found to have significant differences in opioid use patterns and significantly higher health care utilization and associated costs.