PACT Centre Pages - CARDIOVASCULAR PRESCRIBING


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The National Service Framework for Coronary Heart Disease (NSF)1 provides standards for preventing CHD in high risk patients in primary care. These aim to identify (a) people with established cardiovascular disease and (b) people at significant risk of cardiovascular disease but who have not yet developed symptoms, particularly those with a CHD risk greater than 30% over 10 years. To comply with the NSF milestones, every practice should have a CHD risk register; protocols for systematic assessment, treatment and follow-up; and clinical audit data no more than 12 months old that show whether people at high risk have received the interventions set out in the NSF. Chapter 11 of the NSF tackles management of heart failure, the majority of cases of which are due to CHD. The burden of heart failure on secondary care can be reduced when patients with or at risk of CHD receive appropriate treatment.

Hypertension

Antihypertensive drug treatment should be initiated in people with sustained systolic pressure greater than 160mmHg or sustained diastolic pressure above 100mmHg. People with blood pressures between 140-159/90-99mmHg should be assessed in relation to the presence or absence of target organ damage, cardiovascular disease, diabetes and a 10 year CHD risk above 15% before deciding whether to treat. Blood pressure below 140/85 mmHg should be the target in patients without diabetes.2 Recent trials provide direct comparisons of the effectiveness of the main groups of antihypertensive drugs. ALLHAT3 included 33,357 patients who were identified as having hypertension and one or more risk factors for CHD events. Three drugs were compared: an ACE inhibitor, a calcium channel blocker and a thiazide diuretic. There was no significant difference between any of the drugs for the primary outcomes of fatal CHD and non-fatal MI. ALLHAT provides evidence to support using a thiazide as first choice therapy in most patients; this is in line with the British Hypertension Society guidelines2 and SIGN guidelines.4 In another recent trial of ACE inhibitors and diuretics for hypertension in the elderly, it was observed that blood pressure control was similar with either, however, treatment with an ACE inhibitor produced better cardiovascular outcomes in male subjects, particularly non-fatal cardiovascular events and MI.5 An increased risk of fatal stroke was seen in the ACE inhibitor group.

Choice of initial therapy should be based on pre-existing conditions, contraindications and cost-effectiveness. When blood pressure is uncontrolled by one drug there are two options; add-on therapy, or change to a different drug class. In ALLHAT 40% of patients needed more than one antihypertensive drug to reach the target blood pressure.3 Which drug to add next will depend on the initial choice of therapy; the Birmingham system provides a method for selecting add-on therapy.4 Insufficient evidence is available to recommend angiotensin II receptor antagonists (AIIRAs) as first line therapy in hypertension. They may be considered as an alternative to ACE inhibitors if cough is a limiting adverse effect4 or if people with microalbuminuria or proteinuria have a contraindication to ACE inhibitors.

Patients at lower CHD risk could benefit from statin therapy, but there are concerns about the cost of this approach and whether in routine practice cholesterol concentrations would be reduced sufficiently to decrease mortality. ALLHAT included a lipid lowering arm comparing the use of pravastatin to usual care in hypertensive patients with moderately raised cholesterol.8 Unlike other statin trials there were no significant reductions in mortality, CHD events or stroke with pravastatin. This may be because only modest differences in cholesterol concentrations were achieved between pravastatin and usual care. In the PROSPER trial pravastatin reduced deaths from CHD and non-fatal MIs in elderly people at high risk of developing cardiovascular disease or stroke, however stroke risk was unaffected.9 A recent meta-analysis found that lipid lowering treatment significantly reduces the relative risk of stroke in patients with CHD, particularly when total cholesterol concentration is lowered to under 6.0mmol/l.10 The NSF1 advises that serum cholesterol concentrations should be lowered to less than 5mmol/l (LDL cholesterol 3mmol/l) or by 30% (whichever is greater) using dietary advice and treatment with statins. Recent trial evidence suggests this advice may need to be reviewed.

Atenolol is the most commonly prescribed beta blocker (3.9 million items, quarter to December 2002). However more is spent on bisoprolol than atenolol (£5.9 million and £5.7 million respectively). There are 0.5 million items per quarter for bisoprolol. Ramipril and lisinopril are being prescribed almost equally (1.6 million per quarter each) but slightly more is spent on ramipril (£24.8 million compared to £22.8 million respectively). Although ramipril appears to offer a price advantage over lisinopril when compared using the defined daily dose, the average daily quantity in England is 5mg and ramipril 5mg is more expensive than lisinopril 10mg (See Price Chart). Losartan is the most frequently prescribed AIIRA (0.5 million items, £14.9 million per quarter). 38% of items for calcium-channel blockers are for amlodipine (1.8 million, £36.6 million) and 23% for nifedipine (1.1 million items, £14.5 million).

Use of nitrates remains static, 2.1 million items (£18 million) quarter to December 2002. Nicorandil prescribing is increasing (0.4 million items, £4.3 million). Prescribing of and spending on lipid regulating drugs have both increased around four-fold over the last 5 years (4.9 million items, £161.1 million per quarter). 95% of items for lipid regulating drugs are for statins: simvastatin and atorvastatin are most often prescribed (2.0 million and 1.8 million items per quarter respectively). More is spent on simvastatin (£72.6 million per quarter) than atorvastatin (£58.0 million per quarter).

The total cost of prescribing cardiovascular drugs (NIC/cardiovascular STAR-PU) varies across PCTs (interquartile range 0.57 to 0.70). PCTs in the North (except for North and East Yorkshire, North Lincolnshire and Trent) and in Birmingham and the Black Country spend more on cardiovascular drugs than other PCTs.

REFERENCES

1. National Service Framework for coronary heart disease. Click here for more information
2. British Hypertension Society guidelines for hypertension management 1999: summary BMJ 1999; 319: 630-635
3. The ALLHAT Officers & Coordinators for the ALLHAT Collaborative Research Group. Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic. JAMA 2003; 288: 2981-2997
4. Scottish Intercollegiate Guidelines Network. Hypertension in older people. 2001
5. The Second Australian Blood Pressure Study Group. A comparison of outcomes with angiotensin-converting enzyme inhibitors and diuretics for hypertension in the elderly. N Engl J Med 2003; 348: 583-592
6. NICE. National Clinical Guidelines for Type 2 Diabetes. Blood pressure management
7. Heart Protection Study Collaborative Group. MRC/BHF Heart protection study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet 2002; 360: 7-22
8. The ALLHAT Officers & Coordinators for the ALLHAT Collaborative Research Group. Major outcomes in moderately hypercholesterolemic, hypertensive patients randomized to pravastatin vs usual care. JAMA 2002; 288: 2998-3007
9. PROSPER Study Group. Pravastatin in elderly individuals at risk of vascular disease (PROSPER): a randomised controlled trial. Lancet 2002; 360: 1623-1630
10. Differential effects of lipid-lowering therapies on stroke prevention. A meta-analysis of randomized trials. Arch Intern Med 2003; 163: 669-676
11. Clopidogrel and acute coronary syndrome. Drug and Therapeutics Bulletin. June 2002; 40: 41-42