This study found that persons with IBS symptoms that meet the Rome III criteria have poorer quality of life. Our cohort of community-based IBS sufferers had a mean EQ-5D index score of 0.739 which is comparable to patients who suffer from other serious and debilitating conditions such as chronic ischaemic heart disease, which was shown to have a mean index score of 0.738 in one study [14
]. The prevalence rate of IBS in Singapore has previously been found to be rather high at 8.6% [15
] with a clinic consultation rate of 84% [16
]. These high rates and the significant negative impact contribute to a hefty disease burden and increased healthcare costs to the community.
The literature on Western populations has shown that among the five EQ-5D domains, pain/discomfort was the most adversely affected while self-care was the least affected in IBS sufferers [7
]. In our study, we found that pain/discomfort was most significantly affected in the IBS sufferers as well. In addition to this, the mobility, activity and anxiety/depression domains were also significantly affected among the IBS sufferers. However, the self-care domain was not significantly affected. To our knowledge, no prior quality-of-life studies on IBS in Asia have used the EQ-5D tool. However, a study in China which used SF 36 for IBS patients showed that the domain of “physical function” was not affected [17
]. It has also previously been shown that the self-care domain in EQ-5D strongly correlates with the “physical function” domain in SF 36 [7
]. On the other hand, the number of respondents who reported any problems with self-care was very low [6 out of 449 patients (1.3%)]. Hence, it may not be sufficiently powered to detect any difference between the two groups.
There is a “dose-related” association between anxiety and depression with IBS. Respondents were more likely to have IBS when they had a higher degree of reported anxiety or depression. It is well-recognized that psychological disturbances are common in IBS [1
] and may result in changes in perception of visceral sensations in IBS patients [18
]. However, secondary psychological problems can also develop as a result of a chronic debilitating condition such as IBS. While this cross-sectional study cannot establish a causal relationship, the strong association supports recommendation that psychological disturbances should be actively explored and managed in IBS patients [1
There was a male preponderance in the IBS group (53% vs 42%) but this was not significant on multivariate analysis. One Indian study [19
] has shown a significant association of between males and IBS but most Asian studies have shown parity between the genders [20
]. Our results reinforce the observations that the greatly increased risk of IBS in women reported in the West is not reflected in the Asian community [20
]. The cause of this difference is unknown and warrants further investigation.
Asian studies show IBS is more prevalent in younger and more educated individuals [20
]. Our findings are in line with these observations. In addition, we found IBS was also associated with employment although this difference was not significant on multivariate analysis. This can be explained by the over-representation of retired people in the unemployed group, who are significantly older than the employed group (mean age was 64
years in the unemployed group versus 49
years in the employed group, p
0.001). The association between employment and IBS has not been extensively studied and it would be interesting to explore this association.
There are some limitations in this study. The first is that the study population is from participants in a public symposium focusing on gastrointestinal malignancy. It is likely that many of them may have significant gastrointestinal symptoms and are better educated, both factors which are associated with increased risk of IBS. Hence it is not representative of the general population of the country and data such as prevalence of IBS in this group cannot be extrapolated to the nation. Nonetheless, comparisons of HRQoL and the extent to which the individual domains are affected between IBS and non-IBS respondents are valid. The second limitation is the use of a self-reported questionnnaire for the diagnosis of IBS. Without a formal evaluation by a physician to exclude other diseases, the self-reported questionnaire may have limited accuracy for the diagnosis of IBS. It would be ideal if the conditions set forth by the regional consensus guidelines [1
] were adhered to.