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Laxatives - Different aspects of the same subject

The Medicines Resource Centre (MeReC) Bulletins from Liverpool began in June 1990 after publication of the DoH working paper on improving prescribing. Free to GPs, the bulletins provide immediately usable information on medicines and their effectiveness.

The June 1994 bulletin on the treatment of constipation [1] is typical: a clear statement of the problem, executive summary, background and treatments available and graphics with comparative costs of different treatment choices.

However, there are other aspects to laxative use and constipation. In the UK some 10 million prescriptions are written annually for laxatives, and many more non-prescription laxatives are taken. Two studies from the early '90s are worth considering with the MeReC bulletin.

A better way to go?

It is now well accepted that increased fibre in the diet represents a better way of preventing constipation, rather than uncontrolled, often excessive use of laxatives by people with a poor diet. The elderly particularly have a low fibre intake, with concomitant increased prevalence of constipation. Wholemeal bread, fruit and vegetable consumption is better than taking laxatives.

An Australian study from 1991 [2] examined the effects on laxative sales of two methods of promoting increased consumption of wholemeal/wholegrain bread by the elderly. These studies of community intervention were conducted in three small towns on the mid-north coast of New South Wales. The towns had populations of 1400 to 1800; one was used as a control (CON), while in two others a community organisation strategy (COS) involving the media, community activities and social marketing principles using the theme " Bread: It's a Great Way to Go " was compared with a patient education strategy (PES) through local doctors to patients over 55 years.

The main outcome measures were the sales of wholemeal/wholegrain bread and laxatives before and after the 4-month campaigns.


Results

The effectiveness of the community organisation strategy compared with patient education strategy was overwhelming. The PES community was no different from the control community, with trivial changes in sales of bread and laxatives. By contrast the COS community recorded a 60% increase in bread sales and a 60% fall in laxative sales - highly significant results before a statistical test was even thought of.

What is COS?

The COS included the media, community events, bread pricing and social marketing. The centrepiece was a pamphlet with the theme "Bread: It's a Great Way to Go" which provided detailed information about bread and its benefits as well as tips for using bread.

Those are the details given in this short report in the Medical Journal of Australia. They don't tell us how much cheaper was the bread - implied by their reference to bread pricing. However, the implication is that the small community of Harrington (population 1659, 40% over 55 years) was subjected to a powerful advertising blitz about the value of bread. It is a shame that the advertising cost per person was not given: it would be interesting to compare with other heavily advertised health promotion messages.

Laxative induced diarrhoea

Another aspect of laxative use in populations is the abuse of laxatives by individuals. If a patient complains of diarrhoea, the GP or gastroenterologist may consider an idiopathic origin, but the very patient most likely to be abusing laxatives is most likely to be economical with the truth when asked directly.

How big is the problem?

A 1992 study from Glasgow provides the answer [3]. Glasgow is fortunate in having superb biochemistry services, and as part of this a laxative screening service using urine samples was established and offered to gastroenterologists covering the West and Central belt of Scotland.

In 49 patients referred to the gastroenterology clinic from GPs for the investigation of diarrhoea, in two patients (4%) the complaint was found to be self-induced.

In 10 patients who had already been extensively investigated for diarrhoea of unknown origin, two (20%) gave positive urine tests for laxatives.

What are the costs and savings?

In eight patients in whom the diagnosis of idiopathic laxative use was unsuspected, an average of £2,807 (range £60 - £10,709) was spent on tests which would have been unnecessary had an earlier laxative screen been performed.

A laxative screen can be conducted on a urine sample using simple thin layer chromatography by any biochemistry laboratory at a cost of about £40. Glasgow estimated that the cost of performing a laxative screen on all patients presenting with diarrhoea was estimated at £600 for each laxative abuser detected compared with unnecessary expenditure of £2,807 per laxative abuser without screening, an 80% saving per laxative abuser.

Conclusion

Perhaps it would be sensible to perform laxative screens on all new patients referred for investigation of diarrhoea.

References:

  1. The treatment of constipation. MeReC Bulletin vol. 5, no 6, June 1994. Available from Medical Resources Centre, Hamilton House, 24 Pall Mall, Liverpool L3 6AL.
  2. G Eggar, K Wolfenden, J Pares, G Mowbray. "Bread: It's a Great Way to Go": Increasing bread consumption decreases laxative sales in an elderly community. The Medical Journal of Australia 1991 155: 820-1.
  3. A Duncan, J Morris, A Cameron et al. Laxative induced diarrhoea - a neglected diagnosis. Journal of the Royal Society of Medicine 1992 85: 203-5.



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