Ischemic heart disease and stroke account for nearly 25% of all deaths worldwide.1 With an increasing array of effective medications for hypertension and hyperlipidemia, the toll exacted by vascular disease should diminish. However, control of these two primary causes of vascular disease has been seriously compromised by under-diagnosis and under-treatment.2,3 National survey data in the US has revealed that only 31% of hypertensive patients studied achieved blood pressure control.4 When hyperlipidemia complicates hypertension, as it does in 20% of hypertensive adults in the US, fewer than 10% of patients achieve treatment goals for both conditions.5 Meeting targets for hypertension and hyperlipidemia has become a focus of quality of care initiatives, which focus on physician responsibility for meeting quality standards, but neglect the role of patient non-adherence to antihypertensive and lipid-lowering medications.6-8 Concurrent adherence to medications for both conditions has not been well-studied to date, but an observational study of over 8,400 patients enrolled in one managed care plan found that only 35% were adherent to both medications six months after initiation.9 Notably, adherence improved significantly when patients started treatment for hypertension and hyperlipidemia simultaneously. This provocative study suggests that approaches to unite treatment for both conditions may help promote adherence.
Because poor adherence to antihypertensive and lipid-lowering therapy is the norm, it is incumbent upon the physician to work closely with the patient to evaluate and address poor adherence. Identification of poor adherence within the context of a brief patient encounter is already challenging but made even more so because patient self-reporting of adherence has notoriously poor sensitivity.10 A recent study of audiotaped physician-patient interactions about hypertension management showed that open-ended questions resulted in a more productive discussion about adherence.11 Alternatively, a self-report tool designed to assess adherence to antihypertensive medication was found to correlate closely with adherence as measured by an electronic monitor.12 Physicians need to take advantage of such advances when evaluating patient adherence to medications to identify those who need extra support. However, until proven otherwise, physicians should assume that all patients will need some support to improve adherence. Several Cochrane systematic reviews have recently evaluated the evidence for specific interventions to improve adherence to antihypertensive or lipid-lowering drugs.13,14 The review of interventions to promote antihypertensive drug adherence included 38 studies of 58 different interventions and concluded that strong evidence supports the value of reducing the number of daily doses.13 Although some research finds that motivational strategies and multi-faceted interventions can improve adherence, these data were deemed inconclusive. At least one study has supported reduction of hypertensive patients' pill burden in addition to limiting the number of daily doses.15
Unfortunately, newer combination agents that reduce the number of pills may be more costly or even unavailable through many prescription drug plans. The Cochrane review of interventions to promote adherence to lipid-lowering medications included only eight studies and no interventions were found to be beneficial from this research.14 However, this review suggested that increased patient-centeredness and engaging the patient in decision-making may be helpful.
These systematic reviews do not consider interventions to promote adherence to both antihypertensive and lipid lowering therapies simultaneously. Based on studies examining adherence to each type of treatment alone, limiting frequency of doses and pill burden should be considered. Alternative interventions include: pill reminders; patient education; support by adherence experts such as pharmacists; and structural changes in medication delivery.16 A recent evaluation of an intervention to improve adherence in elderly patients with hypertension and hyperlipidemia that used face-to-face counseling by pharmacists and a medication blister pack was able to achieve a high level of adherence (80% or greater) by 97% of study subjects at six months and yielded a significant improvement of systolic blood pressure but no significant effect on low-density lipoprotein (LDL)-cholesterol.17 However, implementation of this type of multilayered, intensive intervention will be challenging without financial support for pharmacist cognitive services.
Because adherence to treatment for multiple vascular disease risk factors has been less well studied than adherence to other types of complex drug treatment such as antiretroviral therapy for HIV infection, it is useful to examine promising approaches from that research. Another Cochrane systematic review of interventions promoting adherence to HIV drugs has shown that patient support and educational interventions appear to improve adherence as does targeting practical medication management skills.18 In conclusion, because of data showing that adherence to combined antihypertensive and lipid-lowering therapy decreases rapidly during the first six months of treatment,7,9 attention to adherence needs to start from the beginning of treatment. The weight of evidence currently supports simplifying the drug regimen. Other approaches to consider include: patient education; pill boxes and other forms of reminders; and individual reinforcement at subsequent visits. Therefore, the physician needs to address adherence at each visit, using either open-ended questions or a validated brief questionnaire. As a former surgeon general once put so aptly, patients don't benefit from medications that they don't take. Adherence is a critical barrier to treatment success and should be considered an essential aspect of care.