SAGES Magazine

THE SOUTH AFRICAN GASTROENTEROLOGY REVIEW 2022 | VOLUME 20 | ISSUE 1 | 26 RESEARCH relieving abdominal pain is indirect, in that improving stool frequency can lead to reduced pain. It is also worth noting that in some of the studies, participants were advised to alter their dosage depending on the symptoms experienced. This suggests that the optimal aloe dosage may differ in IBS sub-types, although it may require further investigation. It was initially thought that, because people considered CAM to be more effective than conventional medicine in treating IBS symptoms, the placebo effect would be larger in CAM clinical trials. A meta-analysis comparing CAM treatments for IBS to placebo have found a rather high pooled placebo response rate greater than 40%. However, when compared with the placebo response rate in conventional medicine trials for IBS, the response rate is similar. This suggests that the placebo response rate is not dependent on the type of therapy used, and that it may not be “enhanced” as initially thought by the use of CAM. 38 4.2. Study limitations This systematic review employed a detailed search strategy in sourcing relevant articles; however, considering the widespread use of Aloe, one surprising finding was the paucity of controlled clinical trials. In addition, high attrition rates were evident in two the selected studies 13,14 , one of which was included in the meta-analysis 13 . However, the effect of attrition in this study appears to be negligible, given that the direction of effect was congruent with the other studies in the meta-analysis, as reflected by the low heterogeneity. Another limitation was the lack of access to non- English journals, especially in Chinese as these could only be accessed through Chinese academic institutions. There was also the challenge of dealing with the different ways in which study authors defined response to treatment. Some studies employed continuous scales to rate improvement of symptoms, while others use ordinal scales, all with differences in value ranges. In some studies, only a ≥ 10% improvement in symptoms was considered a response to treatment, while in others a ≥ 50% improvement in symptoms was considered adequate. Thus, the methods used to assess effect estimates were not standardized. More methodological consistency ought to be considered when designing and carrying out clinical trials involving IBS patients. Furthermore, given the variations in formulae of Aloe preparations in the included studies, standardized formulations would be desirable. Nevertheless, the meta-analysis found low heterogeneity amongst the studies. 5. CONCLUSION 5.1. Implications for further research Aloe-containing preparations were more effective than placebo in improving symptoms among all IBS sub- types combined. In sub-group analyses, Aloe was more effective than placebo in the treatment of constipation- predominant IBS, however this was not the case with IBS-D and IBS-M sub-types. Given the variation in the formulae of Aloe preparations in the included studies, generalizability of this finding may be a challenge. Thus, further research with adequately-powered studies using a standardised formulation for Aloe-containing preparations for IBS is advised. While this review has demonstrated sufficient evidence for the use of Aloe in IBS-C, there remains nevertheless, a dearth of knowledge on further IBS- subtypes. This work highlights the need for applying methodological consistency in further studies, including (1) Standardized methods of assessing response to treatment and (2) Standardized symptom rating scales. In addition, adequately-powered studies are warranted especially when considering the high patient attrition rates in some of the reviewed studies. 5.2. Implications for clinical practice The complex and heterogeneous nature of IBS suggests that instead of using one single agent, it may be more effective to use a combination of agents directed at treating each individual symptom. 14 When comparing effect size between those studies that used Aloe by itself with those that used Aloe in combination with other agents, a much stronger effect was visible in the latter. This could be due to the multi-symptom nature of IBS and how the other agents were able to address each symptom more effectively. In conclusion, the results suggest that Aloe may be a safe and effective treatment for patients with IBS-C. However, for patients with IBS-D and remaining IBS sub- types, further large trials are warranted. ACKNOWLEDGEMENTS Contributions of Authors Conception of the review: Francisco Fong, Mashiko Setshedi, Mark Engel Writing of first drafts of the protocol, literature review and manuscript: Francisco Fong Methodological advice: Mark Engel, Mary Shelton (Expert Librarian) Content advice: Mashiko Setshedi, Mark Engel, Inge Smit Data collection: Francisco Fong, Inge Smit Data analysis: Francisco Fong Contributions to editing subsequent versions of the protocol and manuscript: All authors Competing interests The authors report no conflicts of interest Sources of Funding None References 1. Canavan C. CLEP-40245-the-epidemiology-of-irritable-bow- el-syndrome. 2014;71–80. 2. Drossman DA, Camilleri M, Mayer EA, Whitehead WE. AGA technical review on irritable bowel syndrome. Gastroenterology. 2002;123(6):2108–31. 3. Vanuytsel T, Tack JF, Boeckxstaens GE. Treatment of ab- dominal pain in irritable bowel syndrome. J Gastroenterol. 2014;49(8):1193–205. 4. Cuomo R, Andreozzi P, Zito FP, Passananti V, Carlo G De, Cuomo R, et al. Irritable bowel syndrome and food interaction. 2014;20(27):8837–45. 5. Canavan C, West J, Card T. Review article: The economic im- pact of the irritable bowel syndrome. Aliment Pharmacol Ther. 2014;40(9):1023–34. 6. Stanghellini V. Functional Dyspepsia and Irritable Bowel Syn- drome : Beyond Rome IV. 2018;14–7. 7. Talley NJ, Holtmann G. Irritable bowel syndrome and function- al dyspepsia : what can epidemiology tell us about etiology ? Irritable bowel syndrome and functional dyspepsia : what can epidemiology tell us. Expert Rev Gastroenterol Hepatol [Inter- net]. 2018;12(7):633–5. Available from: https://doi.org/10.1080/ 17474124.2018.1476136