This is the largest study to date to examine expertise about HDS among diverse health professionals and trainees, and to assess factors associated with greater need for education. Despite the growth in review articles, continuing education programs and research on HDS available to interested clinicians, there is still substantial room for improvement in knowledge, confidence and communication practices in all professional groups, even in a highly self-selected group with high rates of using HDS. Our expectation that practitioners would be more confident than students was confirmed for physicians and dietitians. Our expectation that higher use of HDS would be associated with higher scores was also confirmed.
The high rate of personal use of HDS in our sample (85%) exceeds the rates reported in other studies of health professionals. For example, in a sample of 533 pharmacists in Minnesota, 53% reported personal use of HDS [22
]. In a survey of dietitians, 51% reportedly consumed HDS themselves [23
]. The higher rates reported in our study may be because we specifically asked about numerous commonly used vitamins and minerals as well as herbs; our respondents were also enrolling in a course to learn more about HDS. Still, we were surprised by the high median number of supplements used daily (4) in the past week. Further analyses are needed to determine factors associated with higher use of HDS among health professionals and whether higher use affects the quality of information provided to patients.
After controlling for multiple factors, knowledge scores were lowest among students and nurses, those who were not actively seeing patients, those using fewer HDS themselves and those under 31 and over 50 years old. Similar factors were associated with less confidence in communicating with patients and with poorer communication skills. Because HDS is a hot topic, we had thought that students and younger professionals might have higher scores; however, in general students and younger professionals actually had lower scores than practitioners over 30 years old. Secular trends do not easily account for the differences in knowledge scores by level of training; it is possible that clinicians acquire some education about HDS as part of practicing their profession. We were surprised that nurses as a group had lower scores on knowledge, confidence and communication practices than other professional groups. This is a new finding, and requires additional research to confirm and understand. However, students in all health professions and nurses in particular represent a prime target for curricula about HDS.
Although physicians had higher knowledge, confidence and communication practices than other professions, as a group they still had substantial room for improvement on all three outcomes, particularly for communication practices. This is consistent with previous studies. In an anonymous quiz about herbal toxicities and adverse herb-drug interactions, physicians had an average score only slightly better than that predicted by chance; better scores were not associated with age or the amount of clinical experience [24
]. In a survey of physician assistants (PAs), only 19% rated their knowledge as excellent or good; 79% rated their preparation in this topic as fair to poor; those who used herbal remedies were more likely to discuss them with patients than PA's who did not use them [25
]. In another physician survey, although 68% reportedly documented patients' use of non-prescription medications, only 47% documented herbal and other alternative treatments or reviewing these therapies before prescribing a new therapy [26
]. In a study of 200 hospitalized patients, only 21% of the HDS used by patients (as revealed by independent personal interview and inspection of home supply) was documented in the medical record [27
]. Clearly, physicians may be aware that patients are using HDS, but they are still not treating discussion about HDS in the same manner as other types of medications [28
From our data, nurses were the professional group with the greatest need for education and training about HDS. In another survey, nurses were relatively unfamiliar with the most commonly used HDS, scoring an average of only 28% correct on a knowledge survey; the topic requiring the most improvement, as in our pilot study, was in terms of side effects and HDS-medication interactions [20
Because many HDS are available in pharmacies without a prescription, shoppers may easily turn to their pharmacist for information; other health care providers may view pharmacists as experts in biochemical therapies such as HDS. In one study, on average, pharmacists reported that patients ask them questions regarding HDS 7 times per 40-hour workweek; other health care practitioners ask an average of 1.3 times per week [22
However, the knowledge and practices of pharmacists in our sample leave substantial room for improvement, similar to a 2001 study, in which only 2.1% of pharmacists reported training specifically about herbal therapy [30
]. The area of knowledge about potential HDS-medication interactions is particularly concerning. For example, in a 1999 investigation, undercover shoppers from Consumer Reports went to 25 pharmacies to buy the herb ginkgo biloba while waiting for a prescription to be filled for an anticoagulant medication. Shoppers held up both products and asked to speak with pharmacists about taking the medication. None of the pharmacists spontaneously cautioned against taking both ginkgo and warfarin concurrently; when asked directly, only 5/25 (20%) warned about potential dangers with this combination [31
Similarly, dietitians may be seen as reliable sources of information about HDS, given the association of many HDS with dietary practices. Our results confirm a 2000 survey of 162 licensed dietitians in Oregon, in which only 10% considered themselves to be knowledgeable about HDS [32
]. As with our study, another survey found greater knowledge scores among dietitians who used HDS themselves than non-users [33
This study has several strengths and limitations. The strengths are its large sample size, the sample of diverse health professionals in practice and in training, the face validity and excellent Cronbach alpha of the study instruments. The limitations of this study include that it was a highly self-selected sample surveyed during one time period. Only 25% of respondents were male, and given women's generally greater interest in complementary therapies, gender-specific self-selection issues might limit the generalizability of these findings. Data are also based on self-report rather than direct observation or medical record review.