Commentary : controversies in NICE guidance on lipid modification for the prevention of cardiovascular disease

The new guidelines from the National Institute for Health and Clinical Excellence (NICE) on lipid modification for the prevention of cardiovascular disease will guide the way we assess cardiovascular risk and treat lipids, both in primary and in secondary care. What are the new aspects, and what is it that might spark controversy in this new publication

Salt and cardiovascular disease

Blood pressure is the most powerful predictor of stroke and other cardiovascular events. The importance of salt (sodium chloride) intake in determining blood pressure and the incidence of hypertension is well established. Furthermore, randomised controlled clinical trials of moderate reductions in salt intake show a dose dependent cause-effect relation and lack of a threshold effect within usual levels of salt intake in populations worldwide. The effect is independent of age, sex, ethnic origin, baseline blood pressure, and body mass. Prospective studies,2 3 4 5 with one exception,6 also indicate that higher salt intake predicts the incidence of cardiovascular events. While widespread support exists for reducing salt intake to prevent cardiovascular disease, the lack of large and long randomised trials on the effects of salt reduction on clinical outcomes has encouraged some people to argue against a policy of salt reduction in populations

Safety and the flying doctor

Interest, curiosity, or dismay—which feeling predominates when we learn from BBC Newsnight that our NHS employs doctors who commute from Poland to cover the out of hours duties that local GPs are unable to work because they are too tired at night? Is it interest in an innovative solution for modern pan-European healthcare provision, curiosity in discovering huge variations in the standard of living across the medical profession in an open Europe, or dismay that the government’s emphasis, that healthcare practice should be based on the best scientific evidence, is little more than lip service? Working continuously for a long time, particularly at night, increases the risk of making errors and causing injury, which is why many professions limit the number of hours of continuous duty. These risks also apply to the medical profession: tired doctors make mistakes that harm patients (N Engl J Med 2004;351:1838-48) and themselve

Pro : Reducing salt intake at population level : is it really a public health priority?

A reduction in salt intake reduces blood pressure, stroke and other cardiovascular events, including chronic kidney disease, by as much as 23% (i.e. 1.25 million deaths worldwide). It is effective in both genders, any age, ethnic group, and in high-, medium- and low-income countries. Population salt reduction programmes are both feasible and effective (preventive imperative). Salt reduction programmes are cost-saving in all settings (high-, middle- and low-income countries) (economic imperative). Public health policies are powerful, rapid, equitable and cost-saving (political imperative). The important shift in public health has not occurred without obstinate opposition from organizations concerned primarily with the profits deriving from population high salt intake and less with public health benefits. A key component of the denial strategy is misinformation (with 'pseudo' controversies). In general, poor science has been used to create uncertainty and to support inaction. This paper summarizes the evidence in favour of a global salt reduction strategy and analyses the peddling of well-worn myths behind the false controversies

Spatial variation of salt intake in Britain and association with socioeconomic status

Objectives: To evaluate spatial effects of variation and social determinants of salt intake in Britain. Design: Cross-sectional survey. Setting: Great Britain. Participants: 2105 white male and female participants, aged 19–64 years, from the British National Diet and Nutrition Survey 2000–2001. Primary outcomes: Participants’ sodium intake measured both with a 7-day dietary record and a 24-h urine collection. By accounting for important linear and non-linear risk factors and spatial effects, the geographical difference and spatial patterns of both dietary sodium intake and 24-h urinary sodium were investigated using Bayesian geo-additive models via Markov Chain Monte Carlo simulations. Results: A significant north–south pattern of sodium intake was found from posterior probability maps after controlling for important sociodemographic factors. Participants living in Scotland had a significantly higher dietary sodium intake and 24-h urinary sodium levels. Significantly higher sodium intake was also found in people with the lowest educational attainment (dietary sodium: coeff. 0.157 (90% credible intervals 0.003, 0.319), urinary sodium: 0.149 (0.024, 0.281)) and in manual occupations (urinary sodium: 0.083 (0.004, 0.160)). These coefficients indicate approximately a 5%, 9% and 4% difference in average sodium intake between socioeconomic groups. Conclusions: People living in Scotland had higher salt intake than those in England and Wales. Measures of low socioeconomic position were associated with higher levels of sodium intake, after allowing for geographic location

Application of Framingham risk estimates to ethnic minorities in United Kingdom and implications for primary prevention of heart disease in general practice : cross sectional population based study

Objective To compare the 10 year risk of coronary heart disease (CHD), stroke, and combined cardiovascular disease (CVD) estimated from the Framingham equations. Design Population based cross sectional survey. Setting Nine general practices in south London. Population 1386 men and women, age 40­59 years, with no history of CVD (475 white people, 447 south Asian people, and 464 people of African origin), and a subgroup of 1069 without known diabetes, left ventricular hypertrophy, peripheral vascular disease, renal impairment, or target organ damage. Main outcome measures 10 year risk estimates. Results People of African origin had the lowest 10 year risk estimate of CHD adjusted for age and sex (7.0%, 95% confidence interval 6.5 to 7.5) compared with white people (8.8%, 8.2 to 9.5) and south Asians (9.2%, 8.6 to 9.9) and the highest estimated risk of stroke (1.7% (1.5 to 1.9), 1.4% (1.3 to 1.6), 1.6% (1.5 to 1.8), respectively). The estimate risk of combined CVD, however, was highest in south Asians (12.5%, 11.6 to 13.4) compared with white people (11.9%, 11.0 to 12.7) and people of African origin (10.5%, 9.7 to 11.2). In the subgroup of 1069, the probability that a risk of CHD >15% would identify risk of combined CVD >20% was 91% in white people and 81% in both south Asians and people of African origin. The use of thresholds for risk of CHD of 12% in south Asians and 10% in people of African origin would increase the probability of identifying those at risk to 100% and 97%, respectively. Conclusion Primary care doctors should use a lower threshold of CHD risk when treating mild uncomplicated hypertension in people of African or south Asian origin

Blood pressure control by home monitoring : meta-analysis of randomised trials

Objective To determine the effect of home blood pressure monitoring on blood pressure levels and proportion of people with essential hypertension achieving targets. Design Meta-analysis of 18 randomised controlled trials. Participants 1359 people with essential hypertension allocated to home blood pressure monitoring and 1355 allocated to the "control" group seen in the healthcare system for 2-36 months. Main outcome measures Differences in systolic (13 studies), diastolic (16 studies), or mean (3 studies) blood pressures, and proportion of patients achieving targets (6 studies), between intervention and control groups. Results Systolic blood pressure was lower in people with hypertension who had home blood pressure monitoring than in those who had standard blood pressure monitoring in the healthcare system (standardised mean difference 4.2 (95% confidence interval 1.5 to 6.9) mm Hg), diastolic blood pressure was lower by 2.4 (1.2 to 3.5) mm Hg, and mean blood pressure was lower by 4.4 (2.0 to 6.8) mm Hg. The relative risk of blood pressure above predetermined targets was lower in people with home blood pressure monitoring (risk ratio 0.90, 0.80 to 1.00). When publication bias was allowed for, the differences were attenuated: 2.2 ( − 0.9 to 5.3) mm Hg for systolic blood pressure and 1.9 (0.6 to 3.2) mm Hg for diastolic blood pressure. Conclusions Blood pressure control in people with hypertension (assessed in the clinic) and the proportion achieving targets are increased when home blood pressure monitoring is used rather than standard blood pressure monitoring in the healthcare system. The reasons for this are not clear. The difference in blood pressure control between the two methods is small but likely to contribute to an important reduction in vascular complications in the hypertensive population