Diagnostic criteria for IBS and IBS subtypes
The ROME IV criteria provide diagnostic criteria for IBS, defined as recurrent abdominal pain at least one day a week with two or more of the following:
- related to defaecation
- associated with a change in stool frequency
- associated with a change in stool form (appearance).
These criteria must be present for three months, with symptom onset at least six months before diagnosis.7 However, it should be noted that functional bowel disorders can coexist, and thus a patient’s symptoms might overlap with other ROME IV criteria.
The ROME IV criteria further subtypes IBS into IBS with constipation (IBS-C), IBS with diarrhoea (IBS-D), mixed IBS (IBS-M) and unclassified IBS (IBS-U) (Box 1).8 A recent large international study on the prevalence of the different IBS subtypes found a similar prevalence for IBS-D, IBS-C and IBS-M at around 30% each and about 5% for IBS-U.8,9 It is important for clinicians to accurately classify patients with IBS into the appropriate subtype, as management of symptoms is influenced by the predominant IBS characteristic, while also empowering patients to identify their main troublesome IBS symptom to guide treatment goals.
Additionally, it is important to consider a holistic approach to IBS management and address common associated disorders, which might worsen IBS symptoms. Patients with IBS frequently have associated conditions such as fibromyalgia chronic pelvic pain, chronic fatigue syndrome and temporomandibular joint disorder. They also have a higher prevalence of mental health disorders; up to half have depression, anxiety or self-identify as a hypochondriac.10,11
If patients fit the ROME IV criteria for IBS, careful history and examination to exclude the presence of alarm symptoms and signs (Box 2) should be undertaken. Patients with alarm symptoms and signs should be referred for specialist gastroenterologist review in a timely manner.