Expert opinion: How low should cholesterol targets go?

There is pressure on GPs to aim for ever lower cholesterol levels, but the benefit is not clear. By Dr Rubin Minhas

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

NSF targets of 5mmol/L for total cholesterol and 3mmol/L for LDL cholesterol are now established in the GMS contract, so many GPs feel reasonably satisfied at having made good progress towards achieving these targets. Yet the abundance of evidence supporting treatment with statins has focused on using specific doses of drugs, rather than targets, so why have targets assumed such importance? And is it justified?

Policymakers require some way of directing the treatment that patients receive to iron out so-called postcode prescribing. The simplest way to do this would be to ensure that GPs practise evidence-based medicine and apply the doses of drugs that have been used in clinical trials.

The problem arises when writing audit-driven documents such as the quality and outcomes framework – specifying the numerous drugs and doses that could be allowed would make the framework a logistical nightmare. However, specifying a cholesterol target provides a simple method of performance monitoring the management of cholesterol.

Policymakers are not the only ones who see the attraction of this approach. Targets also determine the choice of drug available to clinicians. The lower the target, the more potent the drug required to achieve it. In statins, this translates into increased sales of the newer, more potent, compounds and can even require the addition of other drugs as combination therapy. However, before this step can occur, scientific rigour requires that there should be some evidence of benefit and safety. It is this benefit that really determines the value of lower targets.

The evidence
Recent statin trials have focused on newer versus older statins, mainly patent versus off-patent drugs. In other cases, the comparisons have been between higher doses of newer statins versus lower doses of older statins.

The focus has been on demonstrating the benefit of treating to lower levels of cholesterol. The problem is that the additional benefit of more aggressive treatment has been very small and there has been no mortality benefit, even within secondary prevention. For increasing levels of cholesterol reduction, there is a much smaller absolute benefit to be gained.

GPs might reasonably ask if this is worthwhile, particularly because inferences about drug safety are confounded by trial run-in periods and unrepresentative populations that do not allow generalisation to the elderly patients with CHD and multiple comorbidities often seen in general practice.

Benefit can be quantified in terms of numbers needed to treat, the clinically meaningful way of interpreting the benefit of treatment. With higher dose versus lower dose treatment, about 50 people are needed to treat to provide a morbidity benefit – not mortality. Unsurprisingly, numbers needed to harm are higher because harm tends to accrue regardless of the rate at which benefit accrues and to do so more quickly with higher doses. This is the situation for secondary prevention. For primary prevention, the scenario is different. There is no evidence to support lower targets for the primary prevention of CHD.

The choice is either to reduce one risk factor, such as cholesterol, lower and lower, using disproportionately more effort to achieve diminishing value, or to ask whether there are more worthwhile objectives that represent a better use of time, money, or health gain.

Is the current level of cardiovascular risk factor management such that chasing lower targets for a single risk factor is the only thing left that is worth doing? GPs might be better advised to spend their time and energy reducing rates of smoking.

However, not all patients in general practice develop cardiovascular disease and GPs are generalists. There are many other benefits we might like to see for our patients with the fixed resources available in the NHS. We could ask ourselves if the time and resources used to lower one cardiovascular risk factor would benefit our patients more if they were invested in funding new drugs for breast cancer, for example.

The patient’s view
There is little evidence on patients’ evaluation of treatment benefits. What there is suggests that they value health benefits less than GPs, who in turn value benefits less than specialists.

Patients also differ in their evaluation of benefits according to clinical need, which is at best a nebulous term. For clinicians it is often thought of as synonymous with severity of illness. In this respect, patients 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 from which they see little immediate personal benefit.

So where does this leave recommendations for cardiovascular risk factor management? Concordance between doctor and patient requires an honest explanation of the potential benefit and harm. Concordance cannot be imposed; rather, it is an understanding that should exist between both parties.

The key lies in patients’ right to value a benefit on their terms, which requires clinicians to acknowledge their responsibility for describing the potential benefit and harm of treatment in neutral terms. Patient participation is vital and the final say in deciding to commence treatment and adjust dosage belongs to them.

- Dr Rubin Minhas is a GPSI in CHD and Medway PCT CHD lead. He is a member of a NICE appraisal committee, but these views are his personal opinions

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