Table 6.
Main factors contributing to the variability of pharmacoepidemiological data on opioid-induced constipation (OIC)
| Factors related to specific study characteristics |
| Study type and design (e.g. retrospective vs prospective) |
| Setting |
| 1. Specific: |
| Palliative care: hospice, home, outpatient clinic, day hospital |
| Pain therapy: inpatient, outpatient, day hospital |
| Oncology: inpatient, outpatient setting, day hospital |
| Gastroenterology: inpatient, outpatient setting, day hospital |
| 2. Non-specific: |
| Hospital unit (e.g., orthopaedics, rheumatology, rehabilitation): inpatient, outpatient, day hospital |
| Nursing home/disabled care home (long-term care): inpatient |
| Primary care physician/primary care paediatrician: office, home |
| OIC as primary or secondary endpoint |
| Taxonomy related to the different criteria for diagnosis, classification and monitoring |
| Scales used for assessment and monitoring |
| Factors related to the type of healthcare professional and/or healthcare assistant performing the evaluation |
| Type of evaluating professional (specialist or primary care physician, psychologist, nurse, nursing assistant) |
| Type of specialist team (palliative care, pain therapy, oncology, gastroenterology) |
| Level of team sensitivity to a symptom or sign |
| Factors related to the patient and/or family or caregiver (especially important during the assessment phase) |
| Underlying condition and clinical stage during which the study is conducted (e.g. patient with stable or advanced-stage cancer and pain; patient with persistent pain of non-cancer origin) |
| Baseline bowel function (e.g. presence or absence of idiopathic chronic constipation) |
| Diet and lifestyle habits at baseline and during opioid treatment |
| Age, sex, anthropometric data |
| Level of independence and functionality (e.g. bedridden, degree of mobility) |
| State of consciousness |
| Cognitive status and/or severity of cognitive decline |
| Ability to communicate |
| Cultural and psychological/relational/affective aspects relating to the patient (and family/caregiver) that may affect the ability to objectively establish clinical aspects essential for formulating a diagnosis (e.g. nausea, vomiting, stool features) |
| Factors related to opioid therapy |
| Patient opioid-naïve or -experienced |
| Strength of the opioid used (weak vs strong) |
| Speed and duration of action of opioid (rapid-onset, short-acting, long-acting) |
| Method and route of administration (parenteral, oral, transmucosal, spinal) |
| Concurrent pharmacological treatments (with analysis of interference at gastrointestinal level) |
| Factors related to OIC treatment |
| Previous or concurrent general treatments (e.g. enemas, micro-enemas) |
| Previous or concurrent treatment with laxatives (single or combined), with assessment of daily dosing and pharmacological subclass (e.g. osmotics) |
| Pharmacological combination of opioids, laxatives and selective opioid receptor antagonists at gastrointestinal level |