Asthma is a common chronic illness that causes considerable morbidity among minority inner-city populations.1–4
Suboptimal medication adherence is one of the main factors contributing to poor outcomes.26, 27
This study examined the association between CAM use for asthma and ICS adherence among inner-city adults. We found that in these patients, CAM use was associated with decreased ICS adherence but not related to other self-management behaviors. Additionally, CAM use was associated with increased worry about ICS side effects, suggesting that some patients may replace their ICS for CAM because of concerns about the safety of asthma controller medications.
There is limited data in the literature about CAM use and medication adherence. Our results are consistent with those of George et al. who studied this relationship among patients with COPD.12
In this study of 276 patients with COPD, 24% of CAM users had high adherence compared to 43% of CAM non-users. Conversely, Feldman et al. examined this issue among 118 patients with juvenile idiopathic arthritis and found no association between CAM use and medication adherence.13
Similarly, Shalansky et al. studied this relationship among 367 patients taking chronic cardiovascular medication therapy and found comparable rates of adherence among CAM users and non-users.14
Potential explanations for these discrepancies include differences in type and severity of illness, patient population affected, or types of medications prescribed for the disease. Our results are similar to the study of patients with COPD, a disease process similar to asthma, also requiring patients to take inhaled medications. Our study extends the results of prior research by evaluating medication and disease beliefs potentially mediating the relationship between CAM use and medication adherence among patients with chronic disease.
In our study, CAM users had worse asthma morbidity and poorer quality of life. Due to the cross-sectional nature of this study, it is not possible to determine the directionality of this association. Decreased medication adherence may be responsible for worse outcomes among patients using CAM. However, increased severity of illness may lead patients to use CAM in an attempt to achieve better asthma control. Regardless of the mechanism of association, physicians should routinely discuss CAM use with their patients, especially those with increased severity and poor control, as they may be more prone to CAM use and potential medication non-adherence. Other measures of self-management were similar between the two groups, indicating that medication adherence is the primary component of asthma management associated with CAM use.
The differences in certain medication beliefs highlight possible explanations for the decreased adherence among CAM users. Those reporting CAM use were more worried about ICS side effects, which may partially explain decreased adherence to those medications. Also CAM users found their medication schedule more difficult to follow, another potential reason for decreased adherence among these patients. In addition, CAM users were somewhat less likely to believe that ICS would protect them from getting worse (p=0.08). Interestingly, CAM users were more likely to believe they had asthma because their lungs were always a little inflamed, reflecting appropriate understanding of the disease process. Further research is necessary to evaluate if targeting these beliefs can help improve ICS adherence among CAM users.
These results have important implications for the education and counseling of patients with asthma. This study underscores the importance of consistently eliciting a history of CAM use, particularly among patients with poor asthma control. Furthermore, beyond obtaining a history of use, it is important to discuss associated medication beliefs, such as concerns about prescribed medications.27
Although CAM may be acceptable for some patients with preferences for using these products, it needs to be used in conjunction with prescribed ICS to obtain optimal asthma control. By engaging in open and nonjudgmental discussion with patients about CAM use as well as concerns or difficulties regarding ICS, clinicians can potentially improve adherence to ICS, a critical component of asthma self-management.
This study has some strengths and limitations worth noting. Because study subjects were enrolled from two hospital-based outpatient clinics, patients without a regular place of care were not represented in the study. Additionally, we excluded patients with mild intermittent asthma and the impact of CAM use may be different among patients with less severe disease. The questionnaire item assessing CAM use was adapted from a validated survey18
and asked patients about their use of teas, rubs, and herbs for asthma. However, we did not collect data regarding other types of CAM, such as yoga or prayer. The relationship between medication beliefs, adherence to ICS, and CAM use may be different among patients using other types of CAM; thus, our results may not be applicable to these practices. Adherence was assessed using MARS, a self-report measure and potentially less accurate than electronic measures of adherence. However, this scale has been validated and shown to be an accurate predictor of adherence.9, 21, 22
An important strength is that this study is theoretically grounded. Leventhal’s Self-Regulation Model, outlining relationships between health beliefs and disease self-management, has been used extensively to help explain the management of different diseases, including diabetes, hypertension, and heart failure.25, 28, 29
Horne’s necessity/concern framework extends the Self-Regulation Model, which is focused on disease beliefs, by including treatment beliefs as well. Our study builds on these theoretical frameworks to suggest potential mechanisms for ICS non-adherence among patients using CAM.
In summary, we found a strong association between CAM use and medication adherence among inner-city asthmatics. These data can be helpful to healthcare providers in identifying patients who are potentially at increased risk of medication non-adherence. Exploring medication beliefs in an open dialogue with asthmatics who report CAM use could be especially important among inner-city, minority patients, a group who is already at higher risk for asthma morbidity and mortality.