Opioid-related bowel dysfunction: prevalence and identification of predictive factors in a large sample of Italian patients on chronic treatment

Background and Objectives: Opioid-bowel dysfunction (OBD) is a broad range of symptoms potentially associated with opioid therapy. This prospective, multicentric study assesses the prevalence of OBD in pa - tients on analgesic therapy for the treatment of pain from any cause and identifies the factors associated with the onset of this side effect. Materials and Methods: Consecutive pa - tients aged >18 years, on analgesic treatment with opioids, non-steroidal anti-inflammatory drugs (NSAIDs) or other therapies for chronic pain of any aetiology were included in the study. The association of OBD with gender, age, pain aetiology and analgesic treatment was analyzed by multivariate analysis and logistic analysis. Results: In total, 2324 patients were included in the study. The prevalence of OBD symptoms was 63.5%, despite that the wide majority of patients (89.5%) were receiving laxatives. OBD symptoms were judged as directly correlated with analgesic therapy in 85.1% of cases. The highest prevalence of constipation was reported with morphine, whereas the lowest was observed in patients on oxycodone CR and buprenorphine TTS. Statisti - cal analysis showed that patients on opioids have a higher likelihood of experiencing OBD symp - toms than those on NSAIDs or other treatments (66.2% vs 37.0%), and this probability is even higher in those with cancer-related pain (69.3%). Female gender and age >70 years also appeared as risk factors. The logistic analysis indicated that cancer-related pain, increased age and the use of fentanyl are positive predictors of the pres - ence of OBD, whereas the administration of oxi - codone CR was associated with a decreased inci - dence of these symptoms. Discussion: Even with the limitation of any observational experience, this study suggests, for the first time, the existence of some factors predictive of the onset of OBD symptoms in pa - tients on analgesic treatment. Moreover, differ - ent opioids seem to be associated with a differ - ent risk of experiencing these symptoms .