Do we have an alternative for the Rome III gastroduodenal symptom-based subgroups in functional gastroduodenal disorders? A cluster analysis approach.

BACKGROUND: Functional dyspepsia (FD) is a heterogeneous biopsychosocial disorder. The Rome III consensus proposed a subdivision into epigastric pain syndrome and postprandial distress syndrome, based on gastroduodenal symptom pattern only; nausea/vomiting- and belching disorders were classified as separate functional gastroduodenal disorders (FGD). We aimed to investigate an alternative subdivision of FGD, taking into account gastric sensorimotor function, anxiety & depression and 'somatization', besides gastroduodenal symptoms.
METHODS: Gastroduodenal symptom data were available for 857 consecutive FGD patients (Rome II criteria). In a subsample (n=259), additional data were obtained on gastric sensitivity, anxiety, depression and 'somatization'. Two separate cluster analyses were performed. In analysis 1, clustering was based on individual gastroduodenal symptom scores. In analysis 2, gastric sensitivity, anxiety & depression and 'somatization', besides total gastroduodenal symptoms score, were used for clustering. KEY
RESULTS: Analysis 1 identified four clusters, largely supporting the Rome III classification, with early satiation, pain and nausea/vomiting clusters, besides a limited severity cluster (R(2) = 0.32). Analysis 2 suggested a five-cluster solution (R(2) = 0.48). Anxiety, depression and 'somatization' were the most important variables separating the clusters. 'Primary somatization' (with low psychiatric symptom levels) as well as 'secondary somatization' (with high anxiety & depression scores) subgroups were identified, besides three other subgroups characterized by psychiatric/gastroduodenal symptoms, mild anxiety symptoms and limited overall severity, respectively. CONCLUSIONS & INFERENCES: We propose an alternative to the current subgrouping in FGD that is exclusively based on gastroduodenal symptoms. This may have consequences for future classification of FGD, as well as broader relevance towards the debate on subgrouping 'functional somatic syndromes'.