Preventing cardiovascular disease in primary care

The United Kingdom's national service framework for cardiovascular disease¹ is one year old. It describes an ambitious list of standards, milestones, and performance indicators against which the NHS will be held to account. It requires primary care to identify and institute preventive strategies not only for people with established ischaemic heart disease but also for those with a 30% 10 year cardiovascular risk. In this issue Hippisley-Cox and Pringle report a study of 18 computerised general practices to estimate the workload involved in meeting these expectations (p 269).² Is it matched by the benefits gained?

Clearly, the increased workload for primary care is huge. In the absence of additional resources, how should this extra work be prioritised alongside everything else required of primary care? Apparently there will be more doctors and nurses,¹ but given a global shortage where will they come from in the time frame of this framework? Without extra staffing the opportunity costs will be high, so which existing activities should stop?

Most general practitioners accept the desirability of working towards systematic evidence based management of patients with established ischaemic heart disease. Hippisley-Cox has shown that this in itself will be a challenge, particularly as the target levels in the first step aim for blood pressure control better than 140/85 mm Hg, cholesterol concentration less than 5 mmol/l, and, for diabetic patients, meticulous glycaemic control.¹ The recently reported EUROASPIRE I and II follow up studies of secondary prevention further illustrate the size of the gap between what is and what could be done in secondary prevention.³,⁴ Interestingly, several physician-initiated indicators improved (prescribing of lipid lowering drugs, β blockers, and angiotensin converting enzyme inhibitors), while those for which patients are responsible remained the same or worsened (smoking, obesity).

Moreover, if patient centred medicine is accepted as a desirable core value of general practice, we acknowledge the right of patients to make their own health choices. Many choose the discounting approach to healthy lifestyle choices—eat, drink and be merry for tomorrow we die.⁵ Measuring the need for change will not make change happen, nor will simply giving people information.

But assume some patients are willing to change, what of the evidence for screening to identify asymptomatic high risk patients as required by the national service framework? Identifying those with a 30% 10 year cardiovascular risk requires either population screening, an approach not supported by evidence,⁶ or opportunistic assessment of risk, which is neither evidence based nor consistent with equity of access, since the inverse care law applies to coronary risk factor screening and interventions.⁷,⁸ What of the subsequent workload in reducing risk and in follow up? The OXCHECK study employed nurses to run special clinics in general practices and showed modest reductions in cholesterol and blood pressure sustained over three years. The resource requirements led the authors to conclude: “The benefits of health promotion through primary care must be weighed against their costs, and in relation to other priorities.”⁹

The British Family Heart Study used nurse run clinics and showed at most a 12% relative risk reduction in coronary risk scores. It estimated that a practice with 1000 men aged 40–55 would need to employ four full time nurses over 18 months and concluded that alternative strategies were needed.⁷

Assuming all patients with a 10 year absolute risk of 30% could be identified, how effective are multiple risk interventions for primary prevention of coronary heart disease? A Cochrane systematic review of 18 trials concluded: “The pooled effects suggest multiple risk factor intervention has no effect on mortality . . . however, a small but potentially important benefit, up to 10% (relative) reduction in CHD mortality may have been missed.”⁶ Though the effect is greatest in those with the worst risk factor profiles,¹⁰ the intensive interventions used in many of the trials would “far exceed what is feasible in routine practice.”⁶

Is it ethical to encourage primary care to divert resources into primary prevention screening and interventions with such modest benefits? The principles of screening are clear: there must be adequate facilities for diagnosing and treating abnormalities detected and clear benefit to a significant number of participants.¹¹,¹²

Should this disappointing ability to reduce cardiovascular risk in this group surprise us? Consider the asymptomatic individual called for screening. After assessment, the hapless soul is told: “Statistically you have a 30% absolute cardiovascular risk over the next 10 years. The evidence⁷ suggests that if you follow our advice your risk can be reduced by an average of 12% relative, (3.6% absolute), to 26.4% absolute. You should stop smoking, lose weight, change your diet, exercise daily, and take (probably for the rest of your life) medications to lower your blood pressure and cholesterol. These have the following side effects. . . .” Head spinning, the patient re-emerges into the real world of cigarette and fast food advertising, where for decades a culture of peer pressure, image, and immediacy has reigned over individual motivation to choose a healthy lifestyle and adopt a 10-30 year personal risk minimisation strategy.

Population based approaches to promoting primary prevention using similar advertising techniques to the tobacco and food industry could be equally if not more cost effective at encouraging healthy lifestyles than general population screening and counselling.¹³ Investigation of policy initiatives (both fiscal and legislative) is equally important in promoting lifestyle change in society. Smoke free legislation has been effectively introduced in New Zealand despite resistance from the tobacco industry.

More national service frameworks are promised. All converge at the generalist primary care team and compete for scarce time. Those seeking accountability from the health service should acknowledge the workload, morale, and opportunity costs of their targets and timeframes. NSF—not so fast, perhaps?

Primary care p 269