Our findings highlighted the favourable perception of efficacy of herbal remedies held by users who accessed primary healthcare facilities throughout Trinidad. Most users of herbal remedies believed that this healthcare modality was an important and effective mode for health and wellness promotion and disease management, similar to a recent US study [11
]. We also observed that most users believed that herbal remedies were either equally or more efficacious than conventional medicines, and in fact about half of the sample suggested that herbs were more efficacious than conventional medicines. Our findings, coupled with the high prevalence of herbal remedy use in Trinidad, demonstrated the overwhelming endorsement of this healthcare modality by patients accessing primary health care services on the island. Our results corroborated well with a recent survey conducted by Tindle and his colleagues [12
] where a significant number of CAM users perceived that these therapies had greater efficacy than conventional allopathic medicines. In their study most respondents used conventional and CAM modalities concomitantly and rated the perceived efficacy of the combined use as greater than the individual modalities.
Our findings were also similar to other studies where patients' perception of the therapeutic efficacy of CAMs were assessed, in these studies more than half of CAM users perceived that the alternative healthcare modality was responsible for some noticeable improvement in physical or psychological well being [13
]. Recently in Trinidad, 76.9% of physicians who reported the use of herbal remedies were satisfied with the outcome [7
]. However, our present study results were markedly different than the mere 5.2% of urban Hispanics in the US who perceived that herbs were more efficacious than physician-prescribed allopathic medicines [16
]. Our recent survey of asthmatics in Trinidad showed that although 30% of patients reported using herbal remedies to alleviate symptoms, none perceived that these remedies by themselves had greater efficacy than conventional medicines in relieving their symptoms [6
]. However, 35% of herbal remedies users with moderate to severe asthma indicated that herbs when used concomitantly with conventional anti-asthmatic medication "worked better". It may be possible that that the rating of perceived efficacy of herbs is disease specific and correlated to concomitant use with allopathic medicines.
As elsewhere [17
], most herbal users did so concomitantly with allopathic medicines, without the knowledge of their attending physician. They also indicated that concomitant herb-drug use was more beneficial than when either herb(s) or drug(s) were used alone. We propose that this practice could further consolidate the perception that this potentially dangerous practice is safe and encourage further 'uninformed' herb-drug concomitant use. Our reported herb-drug interaction rate of 3 out of 265 (1.1%) is relatively low, but this does not negate the grave importance of public awareness of the potential dangers of herb-drug combinations. Our study showed a relatively high incidence of herb-associated adverse effects in 16 out of 265 respondents (6%).
Previous studies have demonstrated that doctor-patient barriers to effective communication exist and these may contribute to nondisclosure. Although our analysis showed that none of the demographic variables influenced disclosure, other factors such as doctor-patient cultural differences, the GP's perception of patients of lower socioeconomic standing and the patients' perception of the GP's negative attitude towards herbal remedies may be affecting the extent of disclosure [18
In our study, garlic was the most popular herb used and many clinically important garlic-drugs interactions have been identified [21
]. Healthcare professionals are in a unique position to impart current evidence-based information to their patients on known deleterious herb-drug interactions [22
]. In so doing informed decisions could be made in an open and non-judgmental environment regarding the use of herbs alongside allopathic medicines.
Although patients reported subjective improvements in physical and psychological well being this may in some cases be attributable to a placebo effect or the natural history of the disease, and may or may not translate into measurable clinical outcomes. Garlic was used by almost half of our sample and in a significant number for the therapeutic management of hypertension. A recent review highlights some of the cardiovascular benefits of garlic [25
] and may support its use in our sample. Durak et al (2004) demonstrated that a standardized garlic extract increased antioxidant status, decreased plasma cholesterol levels, while decreasing blood pressure in hypertensive patients [26
]. Garlic has also been shown to reduce oxidative stress [27
], a presumed underlying cause of many diseases, and this would indirectly imply its usefulness as a preventative herbal medicine to promote health and wellness.
On the other hand, the perceived efficacy of a particular CAM may not translate into measurable clinical effects as was the case in a study involving chronic hepatitis C patients, where although most patients reported subjective improvements, none had normalized serum transamine activities after CAM use [9
]. Many patients in our study reported the use of herbs for the common cold and cough, with perceived benefits; however, a recent systematic review for echinacea in common cold reported only marginal benefit [29
]. These discrepancies underlie the imperative for well-designed randomised placebo-controlled trials to be conducted for the proper assessment of the clinical efficacy and safety of herbal medicines. These would determine the usefulness of these alternative modalities and the possible integration into mainstream conventional medical practice. These studies would inform physicians and patients alike on the measurable benefits and risks of specific herbal remedies.
An earlier report of patient characteristics at public health care facilities in Trinidad showed that almost half of these patients were unable to pay for conventional health care [30
]. At the time of that study patients complained of poor pharmacy service and chronic unavailability of conventional medicines. Within the last few years the government of Trinidad and Tobago has introduced the chronic disease assistance program (CDAP) which has significantly improved the delivery of allopathic medicines to this disadvantaged sector of society. Nevertheless, this scenario of shortages of medicines over the years raises an interesting question as to how patients managed their health and disease in a compromised public health care system. Most patients in our sample sourced their herbs from their backyards and it may be possible that in actuality conventional medicines were added to the traditional practice of herbal use and not the other way around. Most patients reported using herbs on the advice of relatives and friends and this may point to some degree of traditional knowledge transfer.
Our survey was conducted at public primary health facilities throughout Trinidad and included only patients who confirmed their current or previous use of herbs; this selection bias may have introduced a number of limitations. The demographics of our sample demonstrate that patients accessing public primary healthcare were more likely to have low levels of formal education and income, high unemployment and more likely to be female. This correlates well with previous studies done on the island's public health care system [31
]. Obviously, the sample demographics in our study do not reflect that of the wider Trinidadian society and our results cannot therefore be extrapolated to the general population. Since most patients in the sample did not purchase commercially prepared herbal supplements we were not able to capture the effect of corporate marketing influence in the purchase of commercially prepared herbal supplements in Trinidad.
Another possible limitation of the study could have been that some patients at the visited healthcare facilities may not have considered their customary use of "bush teas" as preventative and they may have been inadvertently excluded. Most patients attend primary healthcare facilities for either minor ailments or chronic disease management. This meant that the only patients with certain categories of diseases (such as hypertension, diabetes mellitus and asthma) or minor ailments were interviewed and that herbal remedies in the self-management of other more severe medical conditions such as HIV/AIDS and neoplasias would have been excluded. This, of course, was reflected in the responses obtained as most patients used herbs for maintenance of health and wellness and for minor ailments such as the common cold, cough and fever. Hypertension was the chronic disease most managed with herbal remedies in the sample.
Although we attempted to use quota sampling for the convenient and advantageous capturing of our sample, it may have been possible that interviewer bias may have been introduced by the non-random selection of patients, resulting in a sample that may not have been truly representative.
Notwithstanding these limitations our study results indicate that the high prevalence of herbal use in Trinidad may be attributable to the patients' underlying belief that herbs are efficacious and in some cases more efficacious than conventional medicines. This high prevalence of herbal use leaves us with little option but to accept that this modality would be around for some time and that important public health concerns must be urgently addressed. We therefore recommend that physicians at these public healthcare facilities become more knowledgeable about herbs so that they would be better able to communicate with their patients, especially with regard to their potential interactions with conventional medicines. We also support the conducting of well-designed randomised controlled clinical trials to establish the safety profile and efficacy of Caribbean medicinal herbs. These evidence-based studies would provide a platform for informed decisions by healthcare providers and more importantly the self-prescribing members of the public.