The implications of noncompliance with antihypertensive medication

Determinants of medication adherence in hypertensive patients: an application of self-efficacy and the Theory of Planned Behaviour

Objective

The study aimed to identify the determinants of medication adherence in a population of hypertensive outpatients. The principle objective of the present study was to determine the utility of self-efficacy and the Theory of Planned Behaviour (TPB) in predicting adherence with antihypertensive medication.

Setting

An outpatient hypertension clinic at the Belfast City Hospital, Northern Ireland.

Method

Outpatients who had attended the hypertension clinic on at least one previous occasion were invited to participate in the study. Participants completed a questionnaire incorporating measures of adherence with medication, medical and sociodemographic factors, together with measures of self-efficacy and the TPB. There were no specific study exclusion criteria.

Key findings

A total of 139 participants took part in the study; 20.9% of the participants reported non-adherence with their prescribed antihypertensive medication. A statistically significant difference in self-efficacy scores between the adherent and non-adherent groups was revealed by a Mann-Whitney test, with adherent patients perceiving higher levels of self-efficacy. Regression analysis with the TPB variables revealed that adherence was predicted by intentions and subjective norms, with 41% of the variance explained. Intention was predicted by attitudes and perceived behavioural control, with 61.9% of the variance explained.

Conclusion

The present study provides support for the use of self-efficacy and the TPB in predicting medication adherence; however, further research is required on the application of the TBP in the prediction of health behaviour. These findings have implications for the design of adherence-enhancing interventions.

Comparison of persistence rates with angiotensin-converting enzyme inhibitors used in secondary and primary prevention of cardiovascular disease

OBJECTIVES

On average, 50% of patients are noncompliant with drugs for chronic health problems, despite their proven efficacy. It is therefore essential to have real-world data to devise suitable methods for improving persistence with these therapies. To measure and compare persistence rates with the angiotensin-converting enzyme inhibitors (ACEIs) in primary and secondary prevention and their determinants.

METHODS

Two cohorts were reconstructed from the Régie de l'assurance maladie du Québec's databases. The subjects had to be newly treated with ACEIs between January 1, 1998 and December 31, 2000. The primary prevention cohort consisted of 4596 hypertensive patients and the secondary prevention cohort of 1620 patients. The cumulative persistence rates were determined by the Kaplan-Meier method. The determinants of nonpersistence were evaluated with a Cox regression model.

RESULTS

The 1-year persistence rates for the nonexclusive use of antihypertensive agents by initial prescribed agent: enalapril, fosinopril, lisinopril, quinapril, and ramipril were 66%, 64%, 69%, 65%, and 72% in the secondary prevention cohort, and of 66%, 72%, 71%, 72%, and 75% in the primary prevention cohort. The adjusted 1.5-year nonpersistence rates in primary prevention were higher for quinapril and enalapril than for ramipril. In secondary prevention all of the ACEIs were equivalent in nonpersistence rate. In secondary prevention cohort, having dyslipidemia, respiratory disease, >or=4 different classes of drugs/month increase the rate of persistence. Among, the primary prevention cohort, the fact of having diabetes, dyslipidemia, respiratory disease, using >or=4 different classes of drugs/month or prior hospitalization increased significantly the rate of persistence. For both cohorts, the fact of having high number of oral doses/day or elevated health-care resource utilization decreased significantly the rate of persistence.

CONCLUSION

The 1.5-year persistence rate was low compared with the threshold of 80% generally accepted. The high-risk patients were less likely to discontinue their treatment. These results can be of help in devising methods for improving the effectiveness of these drugs in routine practice.

Assessing medication adherence in the elderly: which tools to use in clinical practice?

Adherence to prescribed medication regimens is difficult for all patients and particularly challenging for the elderly. Medication adherence demands a working relationship between a patient or caregiver and prescriber that values open, honest discussion about medications, i.e. the administration schedule, intended benefits, adverse effects and costs. Although nonadherence to medications may be common among the elderly, fundamental reasons leading to nonadherence vary among patients. Demographic characteristics may help to identify elderly patients who are at risk for nonadherence. Inadequate or marginal health literacy among the elderly is common and warrants assessment. The number of co-morbid conditions and presence of cognitive, vision and/or hearing impairment may predispose the elderly to nonadherence. Similarly, medications themselves may contribute to nonadherence secondary to adverse effects or costs. Especially worrisome is nonadherence to 'less forgiving' drugs that, when missed, may lead to an adverse event (e.g. withdrawal symptoms) or disease exacerbation. Traditional methods for assessing medication adherence are unreliable. Direct questioning at the patient interview may not provide accurate assessments, especially if closed-ended, judgmental questions are posed. Prescription refill records and pill counts often overestimate true adherence rates. However, if elders are asked to describe how they take their medicines (using the Drug Regimen Unassisted Grading Scale or MedTake test tools), adherence problems can be identified in a non-threatening manner. Medication nonadherence should be suspected in elders who experience a decline in functional abilities. Predictors of medication nonadherence include specific disease states, such as cardiovascular diseases and depression. Technological aids to assessing medication adherence are available, but their utility is, thus far, primarily limited to a few research studies. These computerised devices, which assess adherence to oral and inhaled medications, may offer insight into difficult medication management problems. The most practical method of medication adherence assessment for most elderly patients may be through patient or caregiver interview using open-ended, non-threatening and non-judgmental questions.

Home blood pressure measurement and its relationship with blood pressure control in a large selected hypertensive population

Despite the impressive increase of home blood pressure monitoring (BPM) among hypertensive patients over the last few years, a limited number of studies have analysed the rate of home BPM and its relationship with target blood pressure (BP) control, in representative samples of the hypertensive population. The objectives of the study were first to evaluate the prevalence of home BPM in a large selected group of treated hypertensive patients referred to our outpatient hypertension hospital clinic. Second, to assess the rate of satisfactory clinic BP control in patients with or without familiarity with home BPM. In all, 1350 consecutive hypertensive patients who attended our hypertension centre during a period of 12 months and were regularly followed up by the same medical team were included in the study. After informed consent all patients underwent the following procedures: (1) accurate medical history (implemented by a structured questionnaire on demographic and clinical characteristics, including questions concerning home BPM); (2) physical examination; (3) clinic BP measurement; (4) routine examinations; and (5) standard 12-lead electrocardiogram. A total of 897 patients (66%) out of 1350 (687 men, 663 women, age 58.6 +/- 12.3 years, mean clinic BP 141 +/- 16/87 +/- 9 mmHg ) were regularly practising home BPM. In this group of patients, home BPM was associated with a significantly greater rate of satisfactory BP control (49.2 vs 45.6%, P < 0.01). Patients performing home BPM were more frequently men (54 vs 46%, P < 0.02 ) younger (average age 57.8 +/- 12.0 vs 60.3 +/- 12.7 years, P < 0.001) and with a higher educational level (defined by more than 8 years of school, 71 vs 55%, P < 0.05) than their counterparts. There were no significant differences in duration of hypertension, hypercholesterolaemia, obesity, smoking, diabetes, associated cardiovascular diseases, left ventricular hypertrophy and compliance with drug treatment. This study demonstrates that: (1) home BPM is widely performed by hypertensive patients managed in a hypertension hospital clinic; (2) this practice is associated with a significantly higher rate of clinic BP control; and (3) age, male gender and educational level influence the adoption of home BPM.

Blood pressure levels, risk factors and antihypertensive treatments: lessons from the SHEAF study

OBJECTIVES

The SHEAF study (Self measurement of blood pressure at Home in the Elderly: Assessment and Follow-up) is a 3-year prospective cohort study of French elderly (> or =60 years) hypertensive patients designed to assess whether home blood pressure (HBP) measurement provides additional prognostic information over office blood pressure (OBP) in terms of cardiovascular mortality and morbidity. The objective of the present work is to describe the baseline data of the population enrolled in the SHEAF study with special emphasis on blood pressure control in treated hypertensives.

METHODS

During the 2-week initial inclusion phase, baseline demographics, cardiovascular risk factors, antihypertensive treatments as well as office and home blood pressure were recorded. Baseline OBP was assessed using a mercury sphygmomanometer (three consecutive measurements during two visits performed 2 weeks apart). HBP was performed over a 4-day period (three consecutive measurements in the morning and in the evening).

RESULTS

A total of 4939 (95%) of the 5211 patients included in the SHEAF study were treated with at least one antihypertensive drug. Their ages ranged from 60 to 99 years (mean age 70 +/- 7 years); 49% were men, 12% had a previous history of coronary artery disease, 14% diabetes and 43% a treated dyslipidaemia. A total of 45% of the treated patients received a single antihypertensive drug, 34% two drugs, 21% three drugs or more. Overall 23% of treated hypertensives were normalised at the doctor's office (systolic BP <140 mm Hg and diastolic BP <90 mm Hg) and 27% at home (home systolic BP <135 mm Hg and home diastolic BP <85 mm Hg). Poor blood pressure control was associated with age, an increasing presence of diabetes and prescription of several antihypertensives. The proportion of subjects with controlled blood pressure decrease with age from 26% (60-69 years) to 21% (> or =80 years). Blood pressure control of diabetic patients was particularly poor as only 19% had an OBP <140/90 mm Hg and 6% a blood pressure <130/85 mm Hg. The percentage of patients with controlled OBP decreased from 26% when receiving a single antihypertensive drug to 11% when receiving four antihypertensives or more.

CONCLUSION

In the SHEAF study, less than one-third of the patients had an OBP adequately controlled thus confirming previous studies performed in younger populations. Presence of associated cardiovascular risk factors including diabetes did not give rise to a better blood pressure control. When blood pressure control was assessed using HBP measurement similar results were found. As the beneficial effect of antihypertensive treatment has been particularly well established in the elderly, the data of this study underlines the need for a closer and more rigorous management of elderly hypertensives.

"To better know hypertension": educational meetings for hypertensive patients

BACKGROUND

Pilot educational meetings were conducted to (1) verify the support of hypertensive patients in this initiative; (2) test the knowledge of patients regularly followed-up in our Hypertension Centre Outpatient Clinic concerning problems related to hypertension; (3) improve patients knowledge about hypertension through a formal teaching session, (4) compare the knowledge of these patients with that of a control group.

METHODS

An invitation to participate in an educational program on hypertension was extended to 210 consecutive patients (group I ) followed-up in the outpatient clinic of our Hypertension Centre. Each meeting included four sessions: (1) an interactive phase with electronic devices aimed at evaluating the degree of information about hypertension by means of multiple-choice questionnaires, (2) a traditional teaching session, (3) an interactive phase to assess the compliance to treatment, and (4) a general discussion session. The control group (II) included 144 hypertensive patients referred for the first time to our Hypertension Centre. Before the initial visit the patients were asked to answer a questionnaire identical to that provided to group I during the meetings.

RESULTS

The meetings were attended by 183 out of the 210 patients in group I (participation rate = 87%). The answers to the questions were corrected as a percentage ranging from 73.7 to 95.6 in group I and from 43.9 to 74.7 in group II (p < 0.01). The provision of more detailed information about problems in hypertension was associated with better compliance to treatment and blood pressure control. (BP under treatment 138 +/- 14/83 +/- 7 mmHg in group I, 152 +/- 15/91 +/- 11 mmHg in group II; (p < 0.01).

CONCLUSIONS

Our data indicate that this type of educational approach is appreciated by patients (participation rate 87%) and that the level of knowledge about hypertension and compliance to treatment are greater in selected patients than in control patients.

Compliance with antidepressant therapy and antidepressant discontinuation symptoms

OBJECTIVE

Compliance with antidepressant medication is important in order to achieve all the goals of antidepressant therapy. These goals include symptom resolution, restoration of normal functioning and prevention of relapse or recurrent episodes.

METHOD

We discuss compliance and review adverse symptoms that may occur when antidepressant treatment is abruptly discontinued or interrupted.

RESULTS

The physician's role in managing compliance includes preventing or minimizing the risk for discontinuation symptoms, counselling patients regarding the risk for symptoms if doses are missed and choosing pharmacotherapy that is forgiving of non-compliance. Physicians also need to recognize the symptoms of discontinuation syndrome in order to differentiate patients who are non-compliant from patients who require a dosage adjustment or adjunctive therapy. Finally, physicians need to understand how to treat discontinuation symptoms when they do occur.

CONCLUSION

Since published data indicate that between 30% and 60% of patients do not take their medications as prescribed, non-adherence to antidepressant medication is likely to be a significant clinical issue in the management of many patients.

Compliance and acceptance in antidepressant treatment

Poor compliance with antidepressant medication is widespread in both primary care and psychiatric practice, and is a major obstacle to the effective management of depression. It is often believed that adverse events and a lack of efficacy associated with inappropriate prescribing of older antidepressants are common reasons why patients discontinue treatment prematurely. However, appropriate prescribing of effective and well-tolerated antidepressants does not necessarily guarantee compliance. A patient's core beliefs and attitudes to treatment also influence the chances of successful management, and studies have shown that patients harbour many unfounded beliefs relating to antidepressant medications and their use. The prescribing physician is therefore duty bound not only to ensure that they chose an effective antidepressant with minimal side-effects and prescribe it according to treatment guidelines, but that they actively explore the patient's beliefs and attitudes at the time of treatment. Addressing common misconceptions about antidepressant medications, and undertaking a structured follow-up, have been shown both to enhance compliance and improve treatment outcomes. The choice of newer, more selective antidepressants results in a higher number of patients achieving at least one month of treatment. The choice of a drug with a once-daily treatment regimen (drugs with a longer half-life) and with a low risk for discontinuation symptoms if doses are occasionally missed is also warranted. ( Int J Psych Clin Pract 2001; 5 (Suppl 1): S29-S35).

Eprosartan: a review of its use in the management of hypertension

Eprosartan is a potent and selective angiotensin II subtype 1 receptor antagonist. Results of large (n > 100) randomised double-blind studies in patients with mild, moderate or severe hypertension demonstrated that the antihypertensive efficacy of eprosartan (usually 400 to 800 mg/day as a single daily dose or in 2 divided doses) is significantly greater than that of placebo and at least as good as that of enalapril. In placebo-controlled trials, eprosartan achieved mean reductions from baseline in trough sitting systolic blood pressure of 6.3 to 15 mm Hg and in diastolic blood pressure of 4.1 to 9.7 mm Hg. Response rates associated with once daily administration of eprosartan 400 to 800 mg were approximately double those with placebo. Overall, eprosartan was well tolerated with a similar tolerability profile to that of placebo. In comparative trials, in which the incidence of persistent dry cough was evaluated as the primary end-point, enalapril was several-fold more likely to induce this adverse event than eprosartan (the difference being statistically significant regardless of study population and definition of cough). In conclusion, the angiotensin II receptor antagonist eprosartan is a well tolerated and effective antihypertensive agent that is administered once or twice daily without regard to meals. Eprosartan has a low potential for serious adverse events, and the drug has not been associated with clinically significant drug interactions. Unlike ACE inhibitors such as enalapril, eprosartan does not have a high propensity to cause persistent nonproductive cough. Thus, eprosartan represents a useful therapeutic option in the management of patients with hypertension.

A randomized comparison of a conventional dose, a low dose and alternate-day dosing of bendrofluazide in hypertensive patients

OBJECTIVE

To compare 2.5 mg bendrofluazide daily (the standard antihypertensive dose), 1.25 mg bendrofluazide daily and 2.5 mg bendrofluazide on alternate days, in terms of reduction of blood pressure, patient compliance and adverse effect profile.

DESIGN

A single-blind parallel group trial of patients who were randomly assigned to 16 weeks' treatment with bendrofluazide at doses of 2.5 mg daily, 1.25 mg daily and 2.5 mg every other day after a 4-week placebo run-in period.

SETTING

General practices in the greater Belfast and Lisburn area in Northern Ireland.

PATIENTS

Ninety-three patients with newly diagnosed or previously diagnosed hypertension, who had a mean diastolic blood pressure of 90-110 mmHg after receiving placebo for 4 weeks.

MAIN OUTCOME MEASURES

Reduction in blood pressure, patient compliance and changes in biochemical variables.

RESULTS

Sitting systolic and diastolic blood pressures in members of all three groups were significantly lowered with respect to baseline (P < 0.01) with no differences among groups. Overall mean compliance was 97%. No clear relation between dose and biochemical changes was apparent.

CONCLUSIONS

Bendrofluazide at doses of 1.25 mg daily or 2.5 mg every other day reduces blood pressure as effectively as does the conventional 2.5 mg daily regimen.

Clinical pharmacokinetics of vasodilators. Part II

Stimulating cardiac beta 1-adrenoceptors with oxyfedrine causes dilatation of coronary vessels and positive inotropic effects on the myocardium. beta 1-adrenergic agonists increase coronary blood flow in nonstenotic and stenotic vessels. The main indication for the use of the phosphodiesterase inhibitors pamrinone, mirinone, enoximone and piroximone is acute treatment of severe congestive heart failure. Theophylline is indicated for the treatment of asthma, chronic obstructive pulmonary disease, apnea in preterm infants ans sleep apnea syndrome. Severe arterial occlusive disease associated with atherosclerosis can be beneficially affected by elcosanoids. These drugs must be administered parenterally and have a half-life of only a few minutes. Sublingual or buccal preparations of nitrates are the only prompt method (within 1 or 2 min) of terminating anginal pain, except for biting nifedipine capsules. The short half-life (about 2.5 min) of nitroglycerin (glyceryl trinitrate) makes long term therapy impossible. Tolerance is a problem encountered with longer-acting nitric oxide donors. Knowledge of the pharmacokinetic properties of vasodilating drugs can prevent a too sudden and severe blood pressure decrease in patients with chronic hypertension. In considering the administration of a second dose, or another drug, the time necessary for the initially administered drug to reach maximal efficacy should be taken into account. In hypertensive emergencies urapidil, sodium nitroprusside, nitroglycerin, hydralazine and phentolamine are the drugs of choice, with the addition of beta-blockers during catecholamine crisis or dissecting aortic aneurysm. Childhood hypertension is most often treated with angiotensin-converting enzyme (ACE) inhibitors or calcium antagonists, primarily nifedipine. Because of the teratogenic risk involved with ACE inhibitors, extreme caution must be exercised when prescribing for adolescent females. The propagation of health benefits to breast-fed infants, combined with more women delaying pregnancy until their fourth decade, has entailed an increase in the need for hypertension management during lactation. Low dose hydrochlorothiazide, propranolol, nifedipine and enalapril or captopril do not pose enough of a risk of preclude breastfeeding in this group. The most frequently used antihypertensive agents during pregnancy are methyldopa, labetalol and calcium channel antagonists. Methyldopa and beta-blockers are the drugs of choice for treating mild to moderate hypertension. Prazosin and hydralazine are used to treat moderate to severe hypertension and hydralazine, urapidil or labetalol are used to treat hypertensive emergencies. The use of overly aggressive antihypertensive therapy during pregnancy should be avoided so that adequate uteroplacental blood flow is maintained. Methyldopa is the only drug accepted for use during the first trimester of pregnancy.