While the Rome III classification recognizes functional constipation and constipation predominant IBS (IBS-C) as distinct disorders, recent evidence has suggested that these disorders are difficult to separate in clinical practice.|
Professor Nick Talley and colleagues from Australia identified whether clinical and lifestyle factors differentiate Rome III-defined IBS-C from functional constipation based on gastrointestinal symptoms and lifestyle characteristics.
The team reported that 3260 people randomly selected from the Australian population returned a postal survey.
Functional constipation and IBS-C were defined according to Rome III.
The first model used logistic regression to differentiate IBS-C from functional constipation based on lifestyle, quality-of-life and psychological characteristics.
The second approach was data-driven employing latent class analysis to identify naturally occurring clusters in the data considering all symptoms involved in the Rome III criteria for IBS-C and functional constipation.
The researchers found 206 people that met strict Rome III functional constipation, whereas 109 met strict Rome III IBS-C.
The team indicated that functional constipation patients reported an older age at onset of constipation, were less likely to exercise, had higher mental QoL and less health care seeking than IBS-C.
Latent class analysis yielded one latent class that was predominantly functional constipation, while the other class was approximately half IBS-C and half functional constipation.
The team found that the functional constipation-dominated latent class had clearly lower levels of symptoms used to classify IBS, and was more likely to be male but was otherwise similar in distribution of lifestyle factors to the mixed class.
Professor Talley's team commented, "The latent class analysis approach suggests a differentiation based more on symptom severity rather than the Rome III view."