Joint British Societies’ guidelines: Implications for DSNs

Cardiovascular disease (CVD) remains the leading cause of death in the UK and is also the principle cause of death in people with diabetes – up to 75 % of whom die from CVD (Grant et al, 2003). The JBS 2 guidelines firmly establish that diabetes is a major CV risk factor: the evidence comes from studies such as Haffner et al (1998), which estimate that the risk of CVD in people with diabetes approaches that found in people who do not have diabetes but who have had a previous myocardial infarction. The calculation of a CV risk score is no longer deemed necessary for people with diabetes as all service-users should have access to prevention strategies due to the high risk associated with the condition.

In summary, the JBS 2 guidelines state that CV risk reduction can be achieved through the following. 

• Lifestyle and risk factor intervention.
• Appropriate medication to lower blood pressure, modify lipids, reduce glycaemia.
• Prescribing of drugs that offer cardio protection (such as anti-thrombotic treatments). 

Thus, a multifactorial lifestyle and polypharmacy approach is advised to facilitate addressing all modifiable risk factors thus improving quality and length of life (British Cardiac Society et al, 2005). A summary of the recommended targets and CV protective therapies are shown in Table 1 and Box 1 and discussed in detail below.

Lifestyle targets
A number of lifestyle factors have been shown, through epidemiological and clinical trials, to reduce the incidence of CV events. The key lifestyle interventions outlined in the JBS 2 are: 

• smoking cessation
• healthy food choices 
• regular aerobic physical activity 
• maintenance of optimal weight and body fat distribution (for example, reducing central obesity).

Blood pressure
Meta-analyses and systematic reviews of blood pressure lowering have consistently demonstrated the benefit of blood pressure reduction in reducing CV risk, with the benefit of treatment driven by the quality of blood pressure control (reviewed by Williams et al, 2004). The UK Prospective Diabetes Study (UKPDS Group, 1998) demonstrated that the benefits of blood pressure control outweighed that of glycaemic control. Specifically, the numbers needed to treat to prevent, over 10 years, one patient developing any complication, was 6 for hypertension versus 20 for glycaemic control.

For people with diabetes the target blood pressure is now set at <130/80 mmHg with an audit standard of 140/80 mmHg (British Cardiac Society et al, 2005). This audit standard is the upper limit of blood pressure control: wherever possible the optimal target of 130/80 mmHg should be aimed for.

In June 2006, , the British Hypertension Society produced further guidance in collaboration with the NICE advising that first-line hypertension treatment in those aged 55 years and over or who are of Afro–Caribbean descent should be a calcium-channel blocker or a thiazide. If the individual is under 55 years of age, an angiotensin converting enzyme (ACE) inhibitor should be selected unless there is compelling evidence for the use of another specific class of drugs (such as beta-blockers after a myocardial infarction). This additional guidance was based on evidence of unacceptable levels of increased risk of developing type 2 diabetes when beta-blockers were used first-line (NICE, 2006).

Lipids
CV risk increases directly in relation to total cholesterol levels. The benefit of lipid lowering in reducing CV risk has been demonstrated in numerous randomised and controlled trials and is considered to be even more beneficial in people with diabetes. The ASCOT-LLA trial and the Heart Protection Study demonstrated that lowering LDL-cholesterol levels by 1 mmol/l in high risk people with only moderately raised LDL-cholesterol levels reduced risk of coronary heart disease by between 25 and 36 percent (Sever et al, 2003, Heart Protection Study Group Collaborative, 2002). In the Collaborative Atorvastatin Diabetes Study (CARDS) (Colhoun et al, 2004), 10 mg of atorvastatin given to people with type 2 diabetes without raised cholesterol levels reduced cardiovascular events by 37 % (Colhoun et al, 2004). 

Previously, National Service Framework for diabetes and NICE guidelines specified 5 mmol/l as the target for total cholesterol and 3.0 mmol/l for LDL. The JBS 2 guidelines have reduced the target for total cholesterol to 4.0 mmol/l and LDL cholesterol to 2.0 mmol/l, or the equivalent to a 25 % decrease – whichever is the greatest. The guidelines also state that once these targets have been achieved other aspects of the lipid profile should be considered, such as HDL-cholesterol and triglycerides, although no targets have been set for these. However, a growing body of evidence now supports an even lower target.

All people should receive lifestyle advice to reduce total and LDL-cholesterol, lower triglycerides and increase HDL-cholesterol (British Cardiac Society et al, 2005) 

Glycaemic control
The relationship between blood glucose levels and CV risk is continuous. Every 1 % reduction in HbA_1c is associated with 14 % fewer deaths (Stratton et al, 2000). The JBS 2 guidelines state that optimal glycaemic control is indicated by a fasting or preprandial blood glucose value of 4.0 – 6.0 mmols/l and an HbA_1c reading of ≤ 6.5 %. Recommendations are given for the use of oral agents in type 2 diabetes and insulin is advised where oral agents fail to achieve the audit target of HbA_1c <7.5 %. 

Antithrombotic treatments
These have been shown to have significant positive benefits in people at high risk of cardiovascular disease (Anti-thrombotic Trialist Collaborative, 2002). Individuals for whom antithrombotic treatments are recommended by the JBS 2 are detailed in Box 1.

The role of DSNs and practice nurses in implementing JBS 2
The role of the DSN has traditionally been one of education and helping the individual to manage their glycaemic control. Hypertension and hyperlipidaemia were the domain of doctors and primary care teams. Some may question if there is a role for DSNs to play in CV risk management. However, as the majority of people with diabetes are dying from CVD (Grant et al, 2003), and a growing body of evidence now supports the benefit of CV risk reduction treatment, it is difficult to argue a case against DSNs and practice nurses playing a key role. There is also evidence to support the effectiveness of a nurse-led approach in helping people to achieve blood pressure and lipid targets over traditional physician-led care (New et al, 2003). 

The expansion of nurse prescribing rights has opened up the opportunities further. In May 2006, independent nurse prescribers were given the legal rights to prescribe any licensed drug for any medical condition, (with the exclusion of some controlled drugs), as long as it falls within their own level of experience and competence (Department of Health, 2006). This has enabled nurse prescribers working in diabetes care to independently prescribe agents that previously would have had to be prescribed under a supplementary prescribing partnership with a physician. In line with JBS 2 guidelines the standard medication cocktail for most people with diabetes will include treatments for glycaemic control, blood pressure and lipids in addition to aspirin. All can now be prescribed independently by nurse prescribers who have the experience and competence to do so. 

If all individuals with diabetes are to access CV risk reduction treatment – including young people with type 1 diabetes who may previously not have been considered for such treatments – then a multidisciplinary team approach needs to be established in which all health care providers are involved in delivering and monitoring the effectiveness of interventions. 

The following case review demonstrates how effective nurse-led intervention can be used to implement a CV risk reduction strategy in a person with type 1 diabetes (Box 2).

Conclusion
Modern diabetes strategies now need to focus on tackling all modifiable CV risk factors in everyone with diabetes. This brings implications not only for workload but also for training to ensure that nurses whose roles expand to become qualified prescribers are adequately prepared with the knowledge and skills to assess individuals’ needs and to safely prescribe cardiovascular medication. Services may need to be re-designed and resources established to support a move away from a service that views glycaemic control in isolation from other CV risk factors, thus ensuring all high risk individuals have the opportunity to access care that will reduce CV morbidity and mortality.