Background: Opioids are used increasingly in the management of moderate-to-severe chronic non-cancer pain (CNCP). Opioid-induced bowel disorders (OBD) markedly impact health-related quality of life (HRQoL) and frequently limit medically indicated opioid pharmacotherapy. We assessed the risk factors, and effect of OBD on HRQoL in CNCP patients. We also estimated the likely prevalence of narcotic bowel syndrome (NBS). These effects have been reported in cancer patients but not in CNCP previously.
Methods: Ambulatory CNCP patients (n = 146) taking regularly scheduled opioids were invited to complete the Bowel-Disease-Questionnaire and a pain-sensitive HRQoL instrument. The Rome-II criteria were used to define bowel disorders. Narcotic bowel syndrome was defined as presence of daily severe to very-severe abdominal pain of more than 3 months duration requiring more than 100 mg of morphine equivalent per day.
Key results: Ninety-eight patients (69%) returned the survey. Respondents had taken opioids for 10 days to 10 years (median 365 days) at a median daily dose of 127.5 mg morphine-equivalent (range 7.5-600 mg). Constipation prevalence was 46.9% (95% CI 36.8-57.3), nausea 27% (95% CI 17.2-35.3), vomiting 9% (95% CI 17.2-35.3), and gastro-esophageal reflux disease 33% (95% CI 23.5-42.9). Chronic abdominal pain was reported by 58.2% (95% CI 53.2-73.9) and 6.4%, (95% CI 2.4-13.5) fulfilled the criteria of NBS. Prevalence of constipation increased with duration of treatment. Health-related quality of life was low in patients with chronic abdominal pain.
Conclusion & inferences: Bowel disorders including chronic abdominal pain and NBS are common in patients taking opioids for CNCP. Decreased HRQoL in patients with CNCP is driven by chronic abdominal pain.