The subject of the primary prevention of hypercholesterolaemia is a complex one, well summarised late last year in the prescribers journal.

Epidemiological studies show a strong correlation between the average serum cholesterol of a population and its rate of Coronary heart disease (CHD).

Cigarette smoking, hypertension and diabetes mellitus, although important determinants of CHD risk in high-cholesterol societies such as Britain, have less impact in countries whose populations have low average serum cholesterol There is good evidence that specific groups in both types of society benefit from drug therapy to decrease serum cholesterol, both in terms of decreased CHD risk and overall mortality.

Selection of patients for intervention should not be based on single risk-factors in isolation, eg, high blood pressure on high cholesterol, but rather on detection of patients at high cardiovascular risk who will benefit most from intervention. Although this risk may be the consequence of a considerable increase in one factor as in, for example, accelerated hypertension or familial hypercholesterolaemia, it is more commonly the consequence of the combined effect of increases in several factors which would not increase the risk enough to require drug therapy were they isolated phenomena.

More direct evidence is needed of the benefit, possible harm population cost and individual cost-effectiveness of routine population screening followed by drug treatment of hyperlipidaemia or hypertension. Nevertheless, in the meantime, clinicians need a method of ensuring that drug treatment is directed to those most likely to benefit.

The recently published joint recommendations of the British Cardiac Society (BCS), British Hyperlipidaemia Association (BHA) and the British Hypertension Society (BHS) endorse the earlier Standing Medical Advisory Committee (SMAC) guidelines that patients without known CHD or other major atherosclerotic disease should receive statin therapy, if their CHD risk is 3% annually, or greater.

The joint British guidelines are accompanied by a computer programme, which allows the clinician to predict a patient’s risk of CHD and stroke over 10 years. A knowledge of stroke risk can be important in deciding when to treat mild hypertension.

Conclusions

• Screening should be for CHD risk as a whole, not for individual risk factors such as raised blood pressure or raised cholesterol.

• Serum and HDL cholesterol should be part of a risk assessment, but neither of these measurements need be made in the fasting state.

• Clinical assessment of risk should not be based on clinical judgement alone: it is improved by the use of a computer programme or a chart.

• Statins are indicated in primary prevention of CHD when annual CHD risk is >3%

• Dietary advice requires re-evaluation. At present dietary intervention is not proven.
  

No reference as Prescriber's Journal no longer online

A study in the BMJ in December confirmed that searching electronic databases may uncover only half of all relevant studies and showed the importance of contacting other experts when compiling a systematic review. Over 300 of the references in a review were identified by experts working in the field, of which 40 were found subsequently to be eligible. Twenty-four references (24% of the total number of eligible references) would have been missed entirely without the input of people working in the field.

The lack of sensitivity of electronic databases may be due to problems with indexing: Articles from journals that lie outside of the mainstream (which currently includes primary care) take some years to be electronically indexed; furthermore, subjects which are expanding may not have unique medical subject headings (MeSH terms).

This study quantified the contribution of experts to a systematic review and found them to be an essential source for identifying literature. Appropriate experts should be consulted when performing a systematic review in a developing field that does not have a clearly defined specialist literature.

Bandolier last year quoted a controlled trial on emergency contraception. Emergency post-coital contraception is thought to be underused because it must be prescribed by a doctor and used within 72 hours of intercourse. Getting an appointment in time may be difficult, and there may be a degree of embarrassment.

One of the concerns about making emergency contraception more easily available, for instance through pharmacists without a prescription or by having it available at home, is that it may be mis-used. A randomised study from Scotland suggested that this is not the case.

Women were asked to mail to the study centre if they used emergency contraception. Those with emergency contraception at home could obtain a replacement package. After one year, all the women were sent a questionnaire.  There were 549 women in the treatment and 522 in the control group. The final questionnaire was returned by about 65% of women, and information on births or terminations was available on about 93%.

Women who were given emergency contraception to be kept at home were significantly more likely to use it once than those who had to obtain it from a doctor. There was no difference in the proportion of women using emergency contraception twice or more over the year.

Emergency contraception was used on 387 occasions (248 times in treatment group and 139 times by controls). Twelve pregnancies began in a cycle in which emergency contraception had been used, representing a failure rate of about 3%.

The total number of unintended pregnancies was 18 (3%) in those with emergency contraception at home compared with 25 (5%) in those who had to get it from a doctor. This was not statistically different. During the year, in both groups, the predominant form of contraception changed from condoms to oral contraception.

The fear that emergency contraception kept by women at home would be misused has been undermined by this trial but further confirmatory trials would be most helpful.