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IBS symptoms and quality of life 63 3 comparisons. Although we argue that this adjustment improves the reproducibility of our results, an unnecessarily high false negative rate cannot be ruled out. Because of the small sample size, it is important that our findings are corroborated in other cohorts of patients with IBS. Until then, findings should be considered exploratory and appropriate caution should be taken when interpreting the results of the current study. Strengths of this prospective follow-up study include the heterogeneous and well- characterized Maastricht IBS cohort population, i.e. in-depth phenotyping enables comparison to other large cohorts and future studies should explore possibilities of pooling data from different centers to cluster phenotypes and validate the robustness of findings such as the ones reported here. Moreover, since we have recruited patients from both primary and secondary/tertiary care settings ( Table 3.1 ), our population is representative for the general Dutch IBS population. Another strength is the evaluation of the Rome criteria in a telephonic follow-up interview with patients. Due to the current lack of validated biomarkers, IBS remains a symptom-based diagnosis for which the Rome criteria are used to aid diagnostic accuracy, both in research and clinical settings. 52 Since the Rome criteria have not been developed nor validated as a self- administered questionnaire, asking patients to complete the Rome criteria without supervision by a trained researcher may lead to bias and over- or under-estimation of the actual diagnosis, as previously demonstrated by Lovell et al .. 2 In contrast to earlier studies on follow-up of IBS, our study method implied a complete reevaluation of the diagnosis in a telephonic interview and, thus, allows for a more valid and less biased interpretation of Rome diagnosed IBS prevalence over time. In conclusion, the current prospective study contributes to existing insight regarding symptom evolution over time in IBS patients and showed that 30% of patients did no longer fulfill the Rome III criteria after a five-year follow-up period. However, the decrease in GI symptom severity ( i.e. being Rome III-negative at follow-up), did not impact quality of life nor life satisfaction. Our results indicate that long-term quality of life and general well-being might depend on comorbid psychological symptoms, i.e. affective states, rather than gastrointestinal symptom severity.