Underestimation of the true benefits of antihypertensive treatment: an assessment of some important sources of error

Interventions used to improve control of blood pressure in patients with hypertension

BACKGROUND

Patients with high blood pressure (hypertension) in the community frequently fail to meet treatment goals - a condition labelled as "uncontrolled" hypertension. The optimal way to organize and deliver care to hypertensive patients has not been clearly identified.

OBJECTIVES

To determine the effectiveness of interventions to improve control of blood pressure in patients with hypertension. To evaluate the effectiveness of reminders on improving the follow-up of patients with hypertension.

SEARCH STRATEGY

All-language search of all articles (any year) in the Cochrane Controlled Trials Register (CCTR) and Medline; and Embase from January 1980.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of patients with hypertension that evaluated the following interventions: (1) self-monitoring (2) educational interventions directed to the patient (3) educational interventions directed to the health professional (4) health professional (nurse or pharmacist) led care (5) organisational interventions that aimed to improve the delivery of care (6) appointment reminder systemsOutcomes assessed were: (1) mean systolic and diastolic blood pressure (2) control of blood pressure (3) proportion of patients followed up at clinic

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently and in duplicate and assessed each study according to the criteria outlined by the Cochrane Handbook.

MAIN RESULTS

72 RCTs met our inclusion criteria. The methodological quality of included studies varied. An organized system of regular review allied to vigorous antihypertensive drug therapy was shown to reduce systolic blood pressure (weighted mean difference (WMD) -8.0 mmHg, 95% CI: -8.8 to -7.2 mmHg) and diastolic blood pressure (WMD -4.3 mmHg, 95% CI: -4.7 to -3.9 mmHg) for three strata of entry blood pressure, and all-cause mortality at five years follow-up (6.4% versus 7.8%, difference 1.4%) in a single large RCT- the Hypertension Detection and Follow-Up study. Other interventions had variable effects. Self-monitoring was associated with moderate net reduction in systolic blood pressure (WMD -2.5 mmHg, 95% CI: -3.7 to -1.3 mmHg) and diastolic blood pressure (WMD -1.8 mmHg, 95% CI: -2.4 to -1.2 mmHg). RCTs of educational interventions directed at patients or health professionals were heterogeneous but appeared unlikely to be associated with large net reductions in blood pressure by themselves. Nurse or pharmacist led care may be a promising way forward, with the majority of RCTs being associated with improved blood pressure control and mean SBP and DBP but these interventions require further evaluation. Appointment reminder systems also require further evaluation due to heterogeneity and small trial numbers, but the majority of trials increased the proportion of individuals who attended for follow-up (odds ratio 0.41, 95% CI 0.32 to 0.51) and in two small trials also led to improved blood pressure control, odds ratio favouring intervention 0.54 (95% CI 0.41 to 0.73).

AUTHORS' CONCLUSIONS

Family practices and community-based clinics need to have an organized system of regular follow-up and review of their hypertensive patients. Antihypertensive drug therapy should be implemented by means of a vigorous stepped care approach when patients do not reach target blood pressure levels. Self-monitoring and appointment reminders may be useful adjuncts to the above strategies to improve blood pressure control but require further evaluation.

Cost analysis of different pharmacological treatment strategies in elderly hypertensives

OBJECTIVE

To compare costs for management of hypertension in elderly hypertensives randomized to starting treatment with conventional (beta-blockers/diuretics) therapy or a therapy initiated with a calcium antagonist or an angiotensin-converting enzyme (ACE) inhibitor.

DESIGN

Health economic substudy in the Swedish Trial in Old Patients with Hypertension-2 (STOP Hypertension-2).

SETTING

Outpatient clinics in Sweden. In this health economics substudy, 16/312 participating STOP-2 trial centers were selected.

SUBJECTS

Elderly (70--84 years) patients (n=303) with a systolic and/or diastolic hypertension (or=180 and/or 105 mmHg).

METHODS

Costs for patient management were analyzed and categorized in costs for routine care (protocol-driven costs, PDC), costs for extra visits or care (non-protocol-driven costs, NPDC), and direct drug costs (drug treatment costs, DTC). All calculations are related to costs during the first year of treatment after inclusion in STOP Hypertension-2.

RESULTS

Out of the scheduled visits, a total of 99% were actually performed by the patients. There were no differences in the number of visits between the three treatment groups (diuretics/beta-blockers, calcium antagonists or ACE inhibitors). PDC did thus not differ between the three treatment groups. NPDC were similar in the conventional and calcium antagonist groups and lower than for the ACE inhibitor group. DTC were lower in the conventional treatment group compared with the other two groups. CONCLUSION. In elderly hypertensives in STOP Hypertension-2, total costs for management of hypertension were lower in patients assigned to diuretics, beta-blockers or calcium antagonists compared with ACE inhibitors during the first year of treatment. These results may be relevant to management of elderly hypertensive patients, especially in those patients without compelling indications or contraindications to starting treatment with either of these three main drug alternatives. Notably, with a specific drug regimen there are sizable NPDC such as extra visits and controls associated with symptoms or side-effects of a specific therapy, which significantly add to the total costs of treatment. Such costs, beyond the actual costs for the drugs, are important to realize and evaluate in order to provide the true costs for treatment of hypertensive patients.

Interventions used to improve control of blood pressure in patients with hypertension

BACKGROUND

It is well recognized that patients with high blood pressure (hypertension) in the community frequently fail to meet treatment goals - a condition labeled as "uncontrolled" hypertension. The optimal way in which to organize and deliver care to patients who have hypertension so that they reach treatment goals has not been clearly identified.

OBJECTIVES

To determine the effectiveness of interventions to improve control of blood pressure in patients with hypertension. To evaluate the effectiveness of reminders on improving the follow-up of patients with hypertension.

SEARCH STRATEGY

All-language search of all articles (any year) in the Cochrane Controlled Trials Register (CCTR), Medline and Embase from June 2000.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of patients with hypertension that evaluated the following interventions: (1) self-monitoring (2) educational interventions directed to the patient (3) educational interventions directed to the health professional (4) health professional (nurse or pharmacist) led care (5) organisational interventions that aimed to improve the delivery of care (6) appointment reminder systems. Outcomes assessed were: (1) mean systolic and diastolic blood pressure( 2) control of blood pressure (3) proportion of patients followed up at clinic.

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently and in duplicate and assessed each study according to the criteria outlined by the Cochrane Collaboration Handbook.

MAIN RESULTS

56 RCTs met our inclusion criteria. The methodological quality of included studies was variable. An organized system of regular review allied to vigorous antihypertensive drug therapy was shown to reduce blood pressure (weighted mean difference -8.2/-4.2 mmHg, -11.7/-6.5 mmHg, -10.6/-7.6 mmHg for 3 strata of entry blood pressure) and all-cause mortality at five years follow-up (6.4% versus 7.8%, difference 1.4%) in a single large RCT- the Hypertension Detection and Follow-Up study. Other interventions had variable effects. Self-monitoring was associated with moderate net reduction in diastolic blood pressure (weighted mean difference (WMD): -2.0 mmHg, 95%CI: -2.7 to -1.4 mmHg, respectively. Appointment reminders increased the proportion of individuals who attended for follow-up. RCTs of educational interventions directed at patients or health professionals were heterogeneous but appeared unlikely to be associated with large net reductions in blood pressure by themselves. Health professional (nurse or pharmacist) led care may be a promising way of delivering care, with the majority of RCTs being associated with improved blood pressure control, but requires further evaluation.

AUTHORS' CONCLUSIONS

Family practices and community-based clinics need to have an organized system of regular follow-up and review of their hypertensive patients. Antihypertensive drug therapy should be implemented by means of a vigorous stepped care approach when patients do not reach target blood pressure levels.

Generalizability of guidelines and physicians' adherence. Case study on the Sixth Joint National Commitee's guidelines on hypertension

BACKGROUND

Clinical practice guidelines (CPG) are thought to be an effective tool in improving efficiency and outcomes of clinical practice. Physicians' adherence to guidelines is reported to be poor. We evaluated the relationship between generalizability of guidelines on hypertension and physicians' adherence to guidelines' recommendations for pharmacological treatment.

METHODS

We used the Sixth Joint National Committee's (JNC VI) guidelines on hypertension to evaluate our hypothesis. We evaluated the evidence from controlled clinical trials on which the JNC VI bases its recommendation, and compared the population enrolled in those trials with the American hypertensive population. Data on this population came from the National Health and Nutritional Examination Survey III.

RESULTS

Twenty-three percent of the NHANES population had a diagnosis of hypertension, 11% had hypertension requiring drug treatment according to the JNC VI. Only half of the population requiring treatment would have been enrolled in at least two trials. Rate of adherence to CPG was 69%. We found a weak association between generalizability and physicians' adherence to guidelines. Baseline risk was the major determinant of the decision to treat.

CONCLUSION

JNC VI guidelines may not be generalizable to their target population. We found a relatively poor adherence rate to these guidelines. Failing of completely taking into account the clinical characteristics of the patients may be partly responsible for this lack of adherence.

Is drug treatment of hypertension in clinical practice as effective as in randomized controlled trials with regard to the reduction of the incidence of stroke?

The results from several nonexperimental studies suggest that drug treatment of hypertension in daily clinical practice may not be as effective as in randomized controlled trials. These nonexperimental studies had limitations with regard to the selection of an appropriate control group. The objective of our study was to assess the effect of drug treatment of hypertension under circumstances of everyday medical practice on the incidence of stroke by using a prognostically comparable untreated reference group. Within two prospective, population-based cohort studies among 45,000 men and women 20 years of age and older in the Netherlands, we selected a cohort of 2,301 hypertensive subjects who either received drug treatment for hypertension (N = 1,318) or were untreated for hypertension but were determined to be "candidates" for drug treatment on the basis of their level of blood pressure and the presence of other cardiovascular risk factors (N = 983). Follow-up averaged 4.6 years and was complete for 91% of the hypertensives. Compared with untreated hypertensive subjects who were "candidates" for drug treatment, subjects who received drug treatment for hypertension had, after adjustment for potential confounders, a 39% [95% confidence interval (CI) = 3-61%] reduced risk of stroke. About 46 (95% CI = 29-599) hypertensive patients need to be treated with antihypertensive drugs for 5 years to prevent one stroke in the general Dutch population. When a prognostically comparable reference group is used, the drug treatment of hypertension under circumstances of everyday medical practice appears to be effective in the reduction of the incidence of stroke. The relative risk reduction that we found was similar to those found in randomized controlled trials.

Costs and effects of combining stenting and abciximab (ReoPro) in daily practice

AIM

The combined use of stents and abciximab in percutaneous coronary intervention has been evaluated in the EPISTENT trial. However, the clinical and economic findings in trials are not necessarily generalisable to a general population setting. We conducted a study in daily clinical practice comparing stented and non-stented patients undergoing coronary angioplasty with abciximab administration. Furthermore, we compare our results with the findings of the EPISTENT trial.

METHODS

From 1995 to 1999, refractory unstable patients scheduled for angioplasty and receiving abciximab in a Dutch regional hospital were followed prospectively for 6 months. Total costs were considered in addition to 2 composite clinical endpoints: (1) death or myocardial infarction (MI); and (2) death, MI, or any revascularisation procedure (major adverse cardiac events, MACE).

RESULTS

Stented patients (N=101) experienced less MACE than non-stented patients (N=83) (6.9% vs. 16.9%, OR=0.37, P=0.04). The total costs were similar for stented and non-stented patients (EUR 7 844 vs. EUR 7 904, P=0.93). Adjustment for baseline characteristics yielded similar results, although significance subsided. The relative risk reduction of 44% that we found, closely resembles the 42% that was found in the EPISTENT trial.

CONCLUSIONS

In everyday practice, as in the EPISTENT trial, the addition of a stent to abciximab treatment does seem to reduce the risk of MACE by about 40% at no additional costs.

Prevention of pre-eclampsia: status and perspectives 2000

Because pre-eclampsia is a relatively common complication of pregnancy and forms a major cause of maternal, fetal, and neonatal morbidity and mortality, attempts at prevention are justified, but hampered by the fact that as yet no reliable and acceptable screening tests for women at risk are available. Analysis of the many interventions advocated to prevent or delay the onset of pre-eclampsia reveals that dietary calcium supplementation and prophylactic low-dose aspirin treatment have shown promise of efficacy in small randomized, placebo-controlled trials, but the results of large, multicenter trials are generally disappointing. The disappointing results obtained in large, multicenter trials may in part be explained by the lack of strict criteria for inclusion, late initiation of treatment, use of ill-defined end points, different timing of aspirin ingestion, and low patient compliance. Recent evidence that supplementation with vitamins C and E could prevent pre-eclampsia awaits confirmation. Future clinical trials on prevention of pre-eclampsia should be based on results of basic research.

Concluding remarks. Pursuit of the optimal outcome in hypertension

Achieving the optimal outcome in hypertensive patients requires the selection and use of appropriate strategies to lower the blood pressure and reduce the patient's risk of cardiovascular events such as stroke and coronary heart disease. It also requires ongoing monitoring of the patient to ensure that the desirable end-points of treatment are being met, and that the heart, kidneys and other sites are being effectively protected from potential complications. Current guidelines on the treatment of hypertension continue to emphasise the use of low dose diuretics as appropriate first-line therapy whenever pharmacological intervention is indicated, except where there are positive indications (e.g. coexisting congestive heart failure or diabetic nephropathy) for other classes of drugs. Diuretics have repeatedly been shown to reduce the morbidity and mortality associated with hypertension, both in the elderly and in younger adults, and their combination with other antihypertensive agents (when clinically indicated) permits the use of lower total dosages. The thiazide-related diuretic indapamide has been reported to have a number of advantages over the thiazides, including minimal or no adverse influence on plasma lipids and glucose metabolism, or on kidney function in patients with renal insufficiency. It has also been found to produce regression of left ventricular hypertrophy, which is now accepted as an important objective of antihypertensive therapy. The recently developed sustained release (SR) formulation of indapamide allows use of a lower daily dosage of the drug, thereby improving its efficacy:safety ratio in comparison with immediate release formulations. Clinical studies have confirmed the efficacy of indapamide SR 1.5 mg daily in lowering elevated blood pressure, and this formulation can be considered an appropriate choice whenever a diuretic is indicated for the treatment of hypertension, including elderly hypertensives and, because of its metabolic 'neutrality', hypertensive patients with diabetes.

Current status of sustained release formulations in the treatment of hypertension. An overview

The principal advantages to be gained from controlling the variables of drug release in sustained release formulations are as follows: (i) a more uniform plasma drug profile with fewer occasions when super- or subtherapeutic concentrations of the drug, or its active metabolite(s), occur; and (ii) a smoother therapeutic response over the dosage interval (provided the time-course of drug effects reflects the plasma concentration-time profile). Clinically, this offers the potential to optimise drug therapy and decrease the occurrence of concentration-related adverse effects. In addition, sustained release formulations may increase the likelihood of patient acceptance of therapy, and a once-daily sustained release formulation of a shorter-acting drug that provides a 'residual' therapeutic response at the end of the dosage interval can provide additional 'cover' in comparison with a once-daily conventional (immediate release) formulation. In the treatment of hypertension, there are potential advantages to be gained from continuous 24-hour control of blood pressure (BP), particularly in view of epidemiological evidence linking the apparent underperformance of antihypertensive therapy in some major intervention trials in reducing the occurrence of coronary heart disease to predicted levels with a relative failure to control diurnal BP fluctuations. In this regard, the concept of the trough:peak ratio as a measure of antihypertensive efficacy has gained increasing acceptance during recent years. A sustained release antihypertensive formulation offering an improved plasma concentration-time profile and an adequately high trough:peak ratio may therefore provide more consistent 24-hour BP-lowering activity, with attenuation of early morning BP surges and maximal target organ protection. This, coupled with the fact that sustained release formulations can also provide economic advantages in cardiovascular therapeutics by lowering overall health expenditure (which more than offsets their usually higher acquisition costs in comparison with immediate release formulations), suggests that they may have an increasingly important role to play in the future.