Researchers led by Changhyun Lee searched major electronic databases (specifically, PubMed, EMBASE, MEDLINE, and Cochrane library) to find comparative studies on Irritable Bowel Syndrome (IBS) patients and healthy controls. The subjects were the test subjects in the studies in the major electronic databases, which were selected to be adults over the age of 18. The control group was the control groups in the various comparative studies, which were healthy controls without IBS. The independent variable was the diagnosis of IBS, and the dependent variable was the depression and/or anxiety levels presented in the study or calculated as the mean ± standard deviation. Keywords used to find studies were irritable bowel syndrome, depression, and anxiety, and all studies must be published in or after 2000. To assess article quality, the Newcastle-Ottawa Scale was used, and any article with 4 or less points was excluded.
In total, 2293 IBS patients and 4951 healthy controls from 27 studies were used to conduct the analysis, and depression and anxiety levels were significantly higher in IBS patients (pooled SMD = 0.76; 95% CI, 0.62–0.90; P < 0.001; I2 = 77.2% and pooled SMD = 0.84; 95% CI, 0.67–1.01; P < 0.001; I2 = 85.6%, respectively). In analyses of subtypes of IBS the pooled SMDs of depression and anxiety levels were significantly higher in all subtypes (0.83 and 0.81 for IBS with predominant constipation, 0.73 and 0.65 for IBS with predominant diarrhea, and 0.62 and 0.75 for IBS with mixed bowel habits, with a P-value of less than 0.001). A key advantage of a meta-study such as this one is that one is able to gather large amounts of data from various different samples much more easily, which increases sample size and randomness, contributing to a more accurate view of the population as a whole. However, one disadvantage of relying on data provided by other studies instead of directly conducting studies is that the methodology of the studies may be flawed, or the results of the studies may be recorded using different, incompatible metrics or methods. Increasing the scope of the paper would come in a similar fashion as to the original methodology of the paper but with additional databases to search and pull studies from. Another possible method of increasing the scope of the paper would be to lower quality standards for exclusion; however, this would have the additional effect of diluting the quality of data used. Another interesting question raised in the article itself is the role of gender on psychological factors among IBS patients; the paper itself concludes that “the gender effect on psychological factors among IBS patients could not be determined and should be evaluated in prospective studies.” As said before, a good way to expand scope in order to answer this question is to include additional databases and thus studies. If the sample size of these studies is not large enough, a possibility would be to conduct a study examining gendered effects on mood disorders among IBS patients.
APA Format Citation:
Lee, C., Doo, E., Choi, J. M., Jang, S., Ryu, H., Lee, J. Y., Oh, J. H., Park, J. H., Kim, Y.S. (2017). The Increased Level of Depression and Anxiety in Irritable Bowel Syndrome Patients Compared with Healthy Controls: Systematic Review and Meta-analysis. Journal of Neurogastroenterology and Motility 2017, 23(3). 349-362. https://doi.org/10.5056/jnm16220
