Highlights of this issue
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## July 27, 1999

## Demand for prescriptions

### Two studies show patient demand influences prescribing

Elizabeth Miller and colleagues surveyed 20 Toronto-area family physicians to determine whether perceived patient demand for anti-infectives influenced their prescribing behaviour. Although perceived patient demand was reported in 124 (48%) of 260 physician-patient encounters, physicians did not think that the demand had much influence on their decision to prescribe an anti-infective in almost 80% of cases. However, when clinical need was uncertain, physicians said they were influenced "moderately" or "quite a bit" by perceived patient demand in over 50% of cases, and 28 (82%) of 34 patients seeking an anti-infective were prescribed one.

In another study on prescribing habits, Nicole Damestoy and colleagues interviewed 9 physicians who offered consultation services for community-living elderly people in a suburban region of Montreal. They found that many of the physicians had negative perceptions of the aging process, felt that long-term use of psychotropic medication is justified and often acceded to patient demand for psychotropic medications for reasons other than clear medical indication.

## Smith-Lemli-Opitz syndrome

### A treatable cause of mental retardation

Smith-Lemli-Opitz syndrome is the second most common treatable inherited error of metabolism causing mental retardation. Recent developments-a biochemical diagnostic test and the discovery of a potentially beneficial therapy-provide an opportunity for family physicians to facilitate early diagnosis, treatment and genetic counselling. Malgorzata Nowaczyk and colleagues review the often subtle clinical features of the syndrome and describe the promising results of therapy with dietary cholesterol supplementation. Figure 1

![Figure1](http://www.cmaj.ca/https://www.cmaj.ca/content/cmaj/161/2/121/F1.medium.gif)

[Figure1](http://www.cmaj.ca/content/161/2/121/F1)

Figure 1. 

## Excess use of parenteral vitamin B12

### Problems remain

After examining the billing records of Ontario physicians over a 1-year period Carl van Walraven and David Naylor found that 23 651 elderly patients were given regular vitamin B12 injections. Of the 16 707 patients receiving long-term therapy, 3303 (19.8%) were given injections more often than once every 4 weeks, even though no authoritative sources support the practice. These findings suggest that some primary care physicians are administering unnecessary vitamin B12 injections to elderly patients.

## Irritable bowel syndrome

### A patient-centred approach

William Paterson and colleagues report the results of a consensus conference on irritable bowel syndrome, an illness that can be extraordinarily frustrating both to patients who suffer from it and to physicians who try to diagnose and treat it. The authors provide a guide to diagnosis using symptom criteria, describe what little is known about the pathophysiology of the disease and recommend a treatment regimen based largely on symptom management. Figure 2

![Figure2](http://www.cmaj.ca/https://www.cmaj.ca/content/cmaj/161/2/121/F2.medium.gif)

[Figure2](http://www.cmaj.ca/content/161/2/121/F2)

Figure 2. 

## Cardiovascular and cancer mortality

### Study shows ethnic variation in rates

Using data from the Canadian Mortality Database and information on ethnic background from the population census, Tej Sheth and colleagues calculated age-standardized death rates by cause per 100 000 population from 1979 to 1993. The rates of death from ischemic heart disease were highest among Canadians of south Asian origin (men 320.2, women 144.5) and European origin (men 319.6, women 109.9) and were markedly lower among Canadians of Chinese origin (men 107.0, women 40.0). The rates declined significantly in all 3 groups over the study period. The rates of death from cerebrovascular diseases also declined over time but were relatively low (below 50) and showed less variation by ethnic group. The rates of death from cancer were highest and on the rise among Canadians of European origin (men 343.6, women 236.2). In an accompanying editorial, Jennifer O'Loughlin describes the challenges of understanding the true relation between ethnic background and disease.