Chest pain in primary care

This study was set up as a review to ascertain the value of a range of methods - including clinical features, resting and exercise electrocardiography, and rapid access chest pain clinics (RACPCs) - used in the diagnosis and early management of acute coronary syndrome (ACS), suspected acute myocardial infarction (MI), and exertional angina.

A Monte Carlo simulation was performed evaluating different assessment strategies for suspected ACS, and a discrete event simulation evaluated models for the assessment of suspected exertional angina.

For acute chest pain, no clinical features in isolation were useful in ruling in or excluding ACS, although the most helpful clinical features were pleuritic pain and pain on palpation. ST elevation was the most effective ECG feature for determining MI and a completely normal ECG was reasonably useful at ruling this out.

Pre-hospital thrombolysis on the basis of ambulance telemetry was more effective but more costly than if performed in hospital. In cases of chronic chest pain, resting ECG features were not found to be very useful. For an exercise ECG, ST depression performed only moderately well. Other methods of interpreting the exercise ECG did not result in dramatic improvements in these results. Weak evidence was found to suggest that RACPCs may be associated with reduced admission to hospital of patients with non-cardiac pain, better recognition of ACS, earlier specialist assessment of exertional angina and earlier diagnosis of non-cardiac chest pain.

In a simulation exercise of models of care for investigation of suspected exertional angina, RACPCs were predicted to result in earlier diagnosis of both confirmed coronary heart disease (CHD) and non-cardiac chest pain than models of care based around open access exercise tests or routine cardiology outpatients, but they were more expensive.

The benefits of RACPCs disappeared if waiting times for further investigation (e.g. angiography) were long (over 6 months).

Overall where acute coronary syndrome is suspected, emergency referral is justified. ECG interpretation in acute chest pain can be highly specific for diagnosing MI. Immediate testing with troponins is cost-effective in the triaging of patients with suspected ACS. Resting ECG and exercise ECG are of only limited value in the diagnosis of CHD and the potential advantages of RACPCs are lost if there are long waiting times for further investigation.

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Cancer and  fresh fruit and vegetables – not cut and dried

Riboli and Norat carried out a  a systematic review of case-control and cohort studies of fruit and vegetable intake and cancer risk. It searched for studies between 1973 and 2001, and assessed the risk for each 100-gram daily intake increase.

The review found a large number of studies, and assessed the results for different cancer sites individually. For most cancer sites, case control studies found evidence of a significant risk reduction with increased intake of both fruit and vegetables. Cohort studies, usually more accurate approaches, by contrast, were more often associated with a non-significant risk reduction.

The whole area of work is not easy to investigate. To produce a valid assessment of fruit and vegetable intake means having accurate recall or measurement of dietary variables, and study populations with reasonable differences in dietary intake within populations. The former factor may be inaccurate in case-control studies, which are by nature retrospective. Prospective cohort studies may not have populations with large enough variation in diets to show an effect.

There is also the nature of other factors that are associated with cancer risk, like smoking or physical activity. Where there are many associated factors, isolating the effects of any one will not be easy, especially when all are associated with the most subtle of variables, social class.

The best interpretation is that there is some protection against cancer in diets that are rich in fruit and vegetables. To minimise cancer risk, though, all modifiable factors should be addressed. The most importance is smoking, but will also include other risk factors.

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Cost effectiveness at NICE

This study was set up to assess the results from economic evaluations presented to NICE. A retrospective comparison of evidence submitted to the technology appraisal programme of the National Institute for Clinical Excellence (NICE) by manufacturers of the relevant healthcare technologies and by contracted university based assessment groups was carried out.

The analysis of 54 paired comparisons showed that manufacturers' estimates of cost effectiveness ratios were lower (suggesting a more cost effective use of resources) than those produced by the assessment groups (25 were lower, 29 were the same, none were higher.

Restriction of this dataset to include only one  comparison per appraisal (27 pairs) produced a similar result (21 were lower, two were the same, four were higher.

It is concluded that the cost effectiveness ratios submitted by manufacturers were on average significantly lower than those submitted by the assessment groups. These results show that an important role of NICE's appraisal committee, and of decision makers in general, is to determine which economic evaluations, or parts of evaluations, should be given more credence.

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