Is it really better to lower cholesterol?

NSF targets for cholesterol are just one weapon in the fight against CHD, says Dr Rubin Minhas

GPs have come under pressure from specialist groups to reduce cholesterol through ever-lower targets, at a time when the NHS faces tough decisions over allocating its resources effectively.

With targets of 5mmol/l for total cholesterol and 3mmol/l for LDL cholesterol now established within the GMS quality framework, many GPs are satisfied that they have made progress in the fight to lower cholesterol.

Evidence to support treatment with statins has focused on using specific doses of drugs rather than targets, but targets have assumed greater importance such emphasis on targets may not be justified.

Policymakers desire some way of directing the treatment that patients receive and specifying a cholesterol target provides a simple method of performance monitoring cholesterol management.

Statin trials

Targets also determine the choice of drug available to clinicians. The lower the target the more potent the drug required to achieve it.

With statins, this translates into increased sales of newer, more potent compounds and can require other drugs as combination therapy.

Before this step can occur, however, scientific rigour requires that there should be some evidence of benefit and evidence of safety. It is this benefit that really determines the value that lower targets hold.

Recent statin trials have focused on newer versus older statins. In other cases, the comparisons have been between newer high-dosage statins versus older low-dosage ones.

The focus has been on demonstrating the benefit of cholesterol treatments themselves. The problem has been that any additional benefit of more aggressive treatment has been small and there has not been any mortality benefit shown. GPs might reasonably wonder if it is worth it.

Benefit can be quantified in terms of numbers needed to treat. With higher dose versus lower dose treatment, the NNT is 50 in order to prevent a morbidity benefit – not mortality.

Unsurprisingly, the numbers needed to harm are lower, as harms tend to accrue regardless of the rate at which benefit accrues – in fact, they accrue more quickly with higher doses. This is the situation for secondary prevention.

The primary prevention scenario is different. Evidence simply does not exist to support lower targets for the primary prevention of CHD.

Subsequently, the choice is whether to drill down one risk factor – cholesterol – using disproportionately more effort to achieve diminishing value, or to ask whether there are more worthwhile objectives that represent a better use of time (the GPs’ most precious commodity), money (the health service and taxpayers’ most precious commodity) or health gain (the patients’ most precious need).

Is the current level of cardiovascular risk management such that chasing lower targets for a single risk factor is the only thing left worth doing?

In cardiovascular terms, GPs might be better advised to spend their time and energy in reducing rates of smoking.

Smoking not only causes cardiovascular deaths but also contributes to total mortality through cancers and other smoking-related diseases.

There are many other benefits for which we might like to use the fixed resources available to us in the NHS.

Patient choice

The evidence available suggests that patients value benefits less highly than GPs who, in turn, value health benefits less highly than their specialist colleagues.

Patients also differ in their valuation of health benefits according to their clinical need.

Those recently discharged from a coronary care unit are likely to value an outcome more highly than those with stable cardiovascular disease, while patients being offered treatment for primary prevention place relatively little value on something they see little immediate benefit from.

Genuine concordance between doctor and patient requires an honest explanation of the benefits and harms of the treatment.

In this respect, patient participation is vital and we must recognise that the ultimate say on treatment belongs with the patient. 

Dr Minhas is a GPSI in CHD and Medway PCT CHD Lead. He is a member of the NICE appraisal committee. These are his personal opinions.

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