Complementary and alternative medicine (CAM) includes practices and products of nonmainstream origin that can be used “together with” or “in place” of conventional medicine [1]. In the past two decades, a number of studies investigated the prevalence and patterns of CAM use worldwide [2]. CAM use is now regarded as a global phenomenon, with reports showing 21%-77% of IBD patients using CAM at some point after their diagnosis [2-5]. However, the vast majority of these studies were cross-sectional. Only one study from a population-based cohort of Manitoba investigated the trends of CAM use longitudinally over a period of 4.5 years since 2002 [6]. So far, no study investigated longitudinal data regarding CAM use in the past decade spanning the recent biologic era. Moreover, changes in IBD patients’ perceptions and attitudes toward CAM use over time has not been addressed.

Therefore, we aimed to perform a prospective longitudinal study to determine the changes in the prevalence of CAM use, patterns of CAM use, and the perception and attitude towards CAM between two different time points (2006 and 2014) in a hospital-based IBD cohort in Korea. We further aimed to determine the risk factors associated with previous or current CAM use and consistent CAM use.

In the present study, we sought to investigate changes in prevalence and patterns of CAM use as well as the attitudes towards CAM over an 8-year interval in a hospital-based IBD cohort in Korea. One strength of our study was comparing the responses between both time points from the same initial participants to see if their responses on CAM use have changed over time. Moreover, our study identified predictors for CAM use including predictors for consistent use of CAM at both time points. As the landscape of IBD is ever so dynamic in the past decade in terms of new treatment options and algorithms globally, our longitudinal study may be more reflective of how IBD patients are using CAM during the transition period into the biologic era.

To the best of our knowledge, our study is the first to demonstrate the trend of negative attitudes toward CAM use in the recent years regarding its effectiveness and cost. Our results suggest that significantly more patients feel CAM is less effective and more expensive than conventional treatment compared to about a decade ago. Also, we observed a decreased proportion of those who perceived a positive effect toward CAM among CAM users over the years in the current analysis. However, other factors can potentially influence the results. The availability and approval of more effective therapies including biologic agents for IBD patients may have influenced a relatively positive attitude towards conventional treatment recently [11]. Also, the change of patient environment including the accessibility to medical information from the internet, advent of social media and also activation of on-and-offline IBD communities in the recent years may have influenced our results. Future studies should try to account for the influence of these various factors on the trend of CAM use.

Despite the trend of negative attitude towards CAM across time, the overall proportion of current CAM users slightly increased in 2014 compared to 2006. Also, about 80% of the responders claimed to have used CAM at least once based on the follow questionnaire in 2014. The prevalence of CAM use in the present study is similar to a previous longitudinal study from Manitoba, where 74% of responders used CAM at any time point and about 40% of responders were using CAM at each time point. Interestingly, the proportion of consistent users in our study (21.7%) was similar but slightly higher than what was seen in the Manitoba study (14%) at every time point. Although there was a similar trend of CAM use, the 2 studies were quite different in terms of the patterns of CAM use, the year of which the study was performed, and the type of cohort (hospital-based vs. population-based).

The patterns and types of CAM show a wide variation between cultures and regions. The most common type of CAM used in our study patients at both time points were herbal therapies (predominantly red ginseng) among ever CAM users. This was consistent with a previous Korean study reporting that a quarter of their IBD patients have used red ginseng [12]. In Europe, homeopathy and probiotics are common types of CAM [3,4,13-16], whereas in Canada, probiotics, fish oil, and massage therapy are commonly used among IBD patients [17]. In terms of CAM services, the Manitoba study showed that about 31%-38% of IBD patients use CAM services over time (massage and chiropractic practices were most common in Manitoba) [6], whereas only about 10% of the current CAM users in our study used CAM service at both time points. These variations may reflect a cultural difference or may be caused by a difference in the study methods or classification of CAM as previously suggested by Zezos and Nguyen [2].

Our study investigated risk factors associated with CAM use. Higher education level and previous side effects to conventional treatment were previously reported elsewhere [18-21]. We additionally found prior use of corticosteroids as a significant risk factor in our study. We further looked for risk factors associated with consistent CAM use at both time points; notably, more than half of the current CAM users at each time point used CAM consistently. Interestingly, use of CAM before IBD diagnosis was a significant risk factor. Our results suggest that it is key to ask about the use of CAM even before their diagnosis of IBD, as they may be 2.7 times likely to use CAM consistently over time. Physicians should be aware of these risk factors of CAM use and prepare for proper advice especially in those at risk of using CAM consistently.

Several limitations need to be mentioned. Firstly, a recall bias may have affected our results when answering the questionnaire. Secondly, only about 60% of the initial participants completed the second questionnaire, of whom a better compliance to medical treatment may be expected. As poor compliance to medical treatment could be associated with increased use of CAM [3], the prevalence of CAM in our study may have been underestimated. Thirdly, the generalizability of our results is limited as our study was based on a single referral center. Lastly, we did not account for the change in individuals’ disease activity and the currently used IBD medication over time which may have also influenced the pattern of CAM use and attitude towards CAM.

In conclusion, based on the results of an 8-year follow-up survey, although the attitude toward CAM have become less favorable over time, the majority of IBD patients have experienced CAM with an overall increase of current CAM users over time. Moreover, more than a half of current CAM users tend to use CAM consistently at both time points. Physicians should be aware of the high prevalence of CAM use among IBD patients and prepare for proper advice, especially for those who are at risk of consistent CAM use.