Statins, risk, and personalised care

Cardiovascular risk estimation is fundamental to prescribing guidelines

Statins have consistently been shown to reduce the risk of CVD,4 and greater use of statins at a population level could be a cost effective and clinically effective way of reducing the disease burden. However, the benefits of statins for otherwise healthy individuals are relatively small and, at an individual level, for many people, the benefits may not outweigh the potential harms.5 To balance underuse and overuse international guidelines have, for many years, recommended using estimated cardiovascular risk to guide treatment recommendations. For example, the US Preventive Services Task Force and NICE use a 10 year risk threshold of 10%,26 whereas the World Health Organization uses 20%7 and the European Society of Cardiology use risk categories combined with lipid levels.8

Risk factors for CVD such as age, sex, blood pressure, and lipid concentrations are well established and can be used to estimate risk relatively quickly for most people without existing disease. At a population level, models show benefit which can be used to facilitate economic evaluations for treatment at different risk thresholds. If the threshold is set too high, we miss the opportunity to prevent numerous cardiovascular events; if it is too low, the costs of treatment can outweigh the benefits. Box 1 summarises how NICE treatment thresholds have changed over time in response to changing clinical and economic evidence. While these treatment thresholds are sometimes justified on health economic arguments, they can be at odds with the preferences and values of individual patients.

Using risk estimation in shared decision making

We believe the key risk informed decision is the one made by the patient: whether to take a statin. When people are faced with decisions about their health, it is the clinician’s responsibility to provide balanced information and guidance through shared decision making.12 The clinician should present the options (including doing nothing), explain the potential harms and benefits of the options, then encourage patients to use their preferences and values to arrive at a decision. The benefit someone could expect from statins is proportional to their baseline risk. Statins for primary prevention provide a relative risk reduction of 25-30%,6 so, for example, someone with a 10 year risk of 10% would have their absolute risk reduced by about 3%.However, the potential harms (eg, side effects, inconvenience, labelling, cost) are independent of a person’s cardiovascular risk, although some adverse outcomes are related to individual patient characteristics or comorbidities.

The problem with using cardiovascular risk thresholds to decide on treatment is that these risk thresholds may not concord with the preferences of all patients,13 and informed patient preference should take precedence over clinical guidelines. For example, a 2017 systematic review reported that one third of patients would not consider preventive medication that offered an absolute 5 year risk reduction of 5%¹³—much greater than the 3% benefit someone with a 10% risk over 10 years would get from a statin. In a 2021 survey, the cardiovascular risk had to be 20% before 75% of respondents reported they would want to take statins, and preferences varied considerably.14

The NICE guidelines, as with many other guidelines, do not seem to take account the literature on patient preferences regarding statins when deciding cardiovascular risk thresholds for treatment. NICE does, however, stress the need for shared decision making both within the lipid lowering guidelines and in separate guidance on shared decision making.15 If guideline writers truly believed in shared decision making they would make risk and benefit data more prominent and use thresholds either to promote timely discussion of the options or to make it clear when not to offer a treatment (because the evidence suggests no benefit, or the treatment would be cost prohibitive).

Given patients differ in the level of risk at which they would want to take a statin, we need to consider how to help them understand and use risk in their deliberations. Although it is a simplification, patients will generally take a statin if they believe that the potential benefits outweigh the potential harms. Harms are often conflated with risks of adverse effects and, although these are a concern for many patients when considering taking a statin,16 the potential harms from medications are broader than this and vary between patients. The deleterious effects of taking a medicine can include an altered sense of self and wellbeing, prescription costs, monitoring and review burden, and the hassle of having to take a medication every day.1617 Statins are often the first long term medication a person starts taking, turning them into a lifelong “patient.” People have different views of the harms of medications and, therefore, the point at which the benefits outweigh the harms is variable and may not be attainable given the benefit many medications can reasonably offer.18 Additionally, statins, perhaps more than most drugs, have receive considerable media attention, which may also influence patients’ perceptions.16

People’s interpretation of the values of the benefit and the inconvenience or impact of the harms should inform their decision making. However, people find it difficult to contextualise their individual risks and benefits 19 and so the skill of the clinician is required to help patients weigh-up the relevant information, voice their preferences, and then reach a decision. Such support poses the biggest challenge. Prescribing a statin based on risk thresholds alone, without incorporating patient preferences and values, requires little knowledge, skill, or time. To provide higher quality, personalised care clinicians must have the skills, tools, confidence, and freedom to operate without directive protocols. This is particularly difficult when resources are limited.

Focusing on risk thresholds may restrict shared decision making

Although a risk based approach is better than focusing on surrogate marker thresholds (lipid levels), setting fixed cardiovascular risk thresholds for initiating statins, even with caveats about personal preference, creates a heuristic that may restrict shared decision making: “if the CVD risk is >10%, initiate a statin; if it is lower, then don’t.” We are all “cognitively miserly” so clinicians and patients will use decision making shortcuts (heuristics) when they are available. This could be compounded if external agencies evaluate or incentivise prescribing decisions based on CVD risk thresholds rather than patient preferences.20 The new NICE recommendation including the term “do not rule out” (box 1) could be an attempt to counter this heuristic, but it is not clear it is sufficient to achieve this aim.

Individual risk communication would improve care and credibility

The 2023 NICE recommendation proposes that instead of discounting the option of a statin based on the risk threshold, clinicians should use their clinical judgment to augment risk estimates for individuals and that an individual’s preference for the levels of risk at which they would like to take a statin should be considered. The fact that these two elements of clinical decision making need to be explicitly stated reveals an over-reliance on rigid recommendations in clinical guidelines. If a patient with a 10 year risk of <10% understands the potential harms and benefits of taking a statin and would like to start taking the medication, the clinician should provide them with a statin prescription. Guidelines should not need to explicitly state that clinicians must consider an individual’s particular circumstances and values. Guidelines are a starting point for tenable medical practice, not strict rules to abide by. While guideline writers can help over-ride treatment threshold heuristics through considered use of language and flexible thresholds for offering treatments, we require a cultural shift and a renewed emphasis on shared decision making skills to avoid rigid adherence to guidelines. The careful and skilled application of the recommendations to the individual patient is the foundation of evidence based practice.21

Rather than focusing on when statins are offered it would be preferable to focus on how the offer is presented. A careful, skilled, shared decision making conversation that helps people understand their CVD risk score and consider all their risk factors and their pharmaceutical and non-pharmaceutical options is essential. This allows patients to make the right decision for them, rather than be led by population level risk thresholds. To support this, risk scores can be used as discussion thresholds rather than treatment thresholds, as in the Canadianlipid guidelines that one of us (JM) helped develop.22

We know adherence to statins can be an issue (adherence levels are 18-79%).23 Uncertainty around the necessity, utility, and benefits of treatment, as well as confusion and constantly changing treatment targets, all contribute to poor adherence.24 If a statin does not provide people with the benefit they want, they are unlikely to take the medication regardless of the recommendations of guidelines or their clinician. Perhaps by ensuring we prescribe statins only to patients who have truly chosen to take them and respecting other patients’ right to accept their risks and decline statins, intentional non-adherence to prescriptions would reduce.

Risk reduction conversations

Good quality consultations about cardiovascular risk require a skilled clinician with sufficient time. The “time needed to treat” needs to be taken into account.25 Consideration must be given to the frequency of such an offer and an appropriate targeting strategy. The current NHS screening programme intends that people aged 40 and above are offered a CVD risk assessment every five years, but evaluation of this approach has shown that around three quarters of people attending have a low (<10% over 10 years) cardiovascular risk26 and some higher risk groups may be under-represented.27

Age and sex are the biggest contributing factors to cardiovascular risk, so the population can be stratified initially without full risk data into those who may be at a stage where they would consider medical intervention to reduce their cardiovascular risk and those who would be best supported to reduce their risk through lifestyle improvement. Public health engagement, improved access to personal health information about CVD risk, and support from the multidisciplinary healthcare team could help people better understand their CVD risk. They could then instigate conversations about medication when they feel it’s right for them, rather than at a predefined threshold. Identifying and targeting higher risk people, whose individual “risk threshold” for taking a statin is more likely to be exceeded, should realise greater benefits.

We definitely should be talking about cardiovascular risk estimates when we think about the primary prevention of CVD, but instead of focusing on population level risk thresholds we should pay more attention to how and when risk is calculated and communicated. We should ensure patients receive high quality information and support during and after the decision making process, and help people make the right decisions for them.