LETTERS * CORRESPONDANCE
We will consider for publication only letters submitted in duplicate, printed in letterquality type without proportional spacing and not exceeding 450 words. All the authors must sign a covering letter transferring copyright. Letters must not duplicate material being submitted elsewhere or already published. We routinely correspond only with authors of accepted letters. Rejected letters are destroyed. Accepted letters are subject to editing and abridgement. Seules peuvent etre retenues pour publication les lettres recues en double dont la longueur n'excede pas 450 mots. Elles doivent etre mcanographiees en qualite sans espacement proportionnel. Tous les auteurs doivent signer une lettre d'accompagnement portant cession des droits d'auteur. Les lettres ne doivent rien contenir qui ait etO presentd ailleurs pour publication ou dej& paru. En principe, la redaction correspond uniquement avec les auteurs des lettres retenues pour publication. Les lettres refusees sont detruites. Les lettres retenues peuvent etre abreigees ou faire l'objet de modifications d'ordre redactionnel.
An example of an ecologic fallacy I appreciated the excellent review by Dr. C. Laird Birmingham (Can Med Assoc J 1992; 146: 1389-1340) of Report of the Task Force on the Treatment of Obesity.' The task force was convened to address unsafe practices in the weight loss industry. Its recommendations concern therapeutic measures used in relation to our current knowledge of the mechanisms and treatment of
the Canadian Guidelines for Healthy Weights.2 The authors examined various relations between weight and height and concluded that the standard formula for the BMI (the weight in kilograms divided by the square of the height in metres) gave the closest practical approximation to body fat content in the population. The assessment of fatness is not easy. The gold standard is to weigh the person totally immersed in water to measure the relative density, a research technique not readily available in the home or to commercial weight loss clinics. Measurement of skinfold thickness is a simpler measure of fatness and is used routinely in specialized health assessment facilities. However, the technique is subject to significant error when applied by untrained observers. Weight viewed in isolation is meaningless. Weight and height are easily and reliably measured in the community by means of inexpensive equipment that is generally available. It is recognized that the BMI relates weight to height and not to fatness. However, this can be a valid surrogate for fatness in the normal, semisedentary population.' We acknowledge in our report (page 15) that "while the BMI is a suitable screening instrument for many, it is not appropriate for very muscular people." The task force was convened for and its report is directed to "the safety, competence and integrity of [commercial] weight loss
obesity. I wish to support the use of programs" and therefore -to the the body mass index (BMI) as public and those involved in the recommended in the report. We business of weight loss. It is undelayed the production of the re- likely that weight lifters and othport until the Expert Group on ers who have worked to increase Weight Standards had completed their muscularity will enrol volun-
For prescribing information see page 1380
tarily in such programs. The concern that an ecologic fallacy has been promoted is unlikely to detract from the value of the report to those either running or attending commercial weight loss clinics. John A. Hunt, MB, FRCPC Chairman, Working Group Task Force on the Treatment of Obesity
References 1. Report of the Task Force on the Treatment of Obesity, cat no H39-201/ 1991E, Health Services and Promotion Branch, Dept of National Health and Welfare, Ottawa, 1991 2. Expert Group on Weight Standards: Canadian Guidelines for Healthy Weights, cat no H39-134/1989E, Dept of National Health and Welfare, Ottawa, 1988
Diagnostic testing in chronic urticaria and angioedema D
r~. Jerry Dolovich rightfully points out in his letter (Can Med Assoc J 1992; 146: 1528) that textbooks list numerous diseases that can lead to urticaria and angioedema. They also arbitrarily define these conditions as acute or chronic according to whether the episode lasts less than or more than 6 weeks. It is often mentioned that in chronic cases only rarely is an underlying cause found, and therefore most
such cases are considered idiopathic. With this information physicians may become complacent in treating such conditions with pharmacotherapy without bothering to delineate the underlying cause. Most patients first see their CAN MED ASSOC J 1992; 147 (9)
1303
family physician, who usually tries some antihistamine preparations for a few weeks. When symptoms continue to recur a consultation with a dermatologist is sought. By the time the patient gets to see a consultant that magic 6-week period has elapsed, and the patient is labelled as having chronic urticaria or angioedema. Because of the presumption that most cases of chronic urticaria are idiopathic a consultant may try a different set of medications to provide symptomatic relief. I believe that if symptoms reappear after a couple of episodes physicians should make an effort to identify and remove the causal agent(s) instead of continuing to prescribe medication. In this way some patients may escape the situation of being labelled unnecessarily. I agree that extensive investigations such as routine biopsy, culture, serologic testing and radiography are usually not very rewarding. However, in my experience allergy skin tests are extremely rewarding, not useless, as Dolovich proclaims. I was surprised to note that he cannot think of a single case of chronic urticaria or angioedema in which investigation of the cause had been useful. I have observed that in more than half of such cases a cause can be delineated through testing with a wide variety of food and environmental allergens. The difference in our experience may be due to the different battery of allergens that we use when investigating such cases. On the basis of my personal observations I would urge all physicians to put allergy at the top of the differential diagnosis when dealing with urticaria and angioedema. Food and environmental allergens as a cause of these conditions should be ruled out before extensive and expensive investigations are undertaken. We may thus be able to provide dramatic relief to the patient when allergy is 1304
CAN MED ASSOC J 1992; 147 (9)
the cause instead of offering a suscitation, trauma care, toxicology, prehospital care, disaster planlabel and a handful of pills. ning and the administration and Jagat N. Singh, MD management of emergency departWinnipeg, Man. ments. The focus of residency training in family medicine is on comfamily medicine munity-based Is emergency medicine care, with usuand hospital-ward a specialty? ally no more than 2 months' experience in an emergency departEv mergency medicine is a ment in the 2-year training prospecialty, and it has been gram. This is an excellent baseline recognized by numerous for further training in emergency medical jurisdictions throughout medicine; however, in itself it is the Western world. not adequate or appropriate for a The Quebec controversy on physician intending to devote a the status of emergency medicine large part of his or her practice to discussed in "Is emergency medi- emergency medicine. The days of cine a specialty? Quebec MDs dis- learning emergency medicine by agree over controversial issue" trial and error while working (Can Med Assoc J 1992; 146: alone in the emergency depart1632-1633, 1635-1636), by ment in the middle of the night Michel Martin, has nothing to do have surely passed. with the specialty nature of the The results of Quebec's faildiscipline and everything to do ure to recognize emergency mediwith medical politics and "turf' cine as a specialty are predictable. protection by the Federation des Emergency specialists are no difmedecins omnipraticiens du Que- ferent than other specialists and bec. generally choose to practise where Emergency medicine is a pri- they are recognized. The CMA mary-care specialty historically Physician Resource Databank on linked to general medical practice, Dec. 31, 1986, indicated that of and its development as an in- all physicians practising emergendependent discipline has often cy medicine predominantly or exbeen opposed by the existing clusively only 17% in Quebec, as family-medicine establishment. compared with 41% in the rest of The reason for this opposition is Canada, had postgraduate certifiunclear. Emergency medicine and cation in emergency medicine family medicine are both broadly from either the Royal College of based and devoted to the care of Physicians and Surgeons of Canapatients of all ages and with all da or the College of Family Phystypes of health problems. Howev- icians of Canada. This discrepaner, other than in breadth of scope cy exists even though, ironically, the focuses of the two disciplines the oldest and one of the largest differ substantially: training programs in emergency medicine in Canada is located in Emergency medicine is a specialty Quebec, at McGill University. based on knowledge and skills in- the diagnosis and management of the Quebec already has specialists in acute and emergent aspects of illness emergency medicine working in and injury affecting patients of all age its hospital emergency departgroups with diverse medical, surgical, ments. Absurdly, this specialization is only recognized outside of and behavioral disorders.' the specialists' home province. Quebec will recognize emerIn addition, emergency-medicine medicine as a specialty. The gency physicians have developed special is not if but when. issue reexpertise in cardiopulmonary LE lr NOVEMBRE 1992
We will consider for publication only letters submitted in duplicate, printed in letterquality type without proportional spacing and not exceeding 450 words. All the authors must sign a covering letter transferring copyright. Letters must not duplicate material being submitted elsewhere or already published. We routinely correspond only with authors of accepted letters. Rejected letters are destroyed. Accepted letters are subject to editing and abridgement. Seules peuvent etre retenues pour publication les lettres recues en double dont la longueur n'excede pas 450 mots. Elles doivent etre mcanographiees en qualite sans espacement proportionnel. Tous les auteurs doivent signer une lettre d'accompagnement portant cession des droits d'auteur. Les lettres ne doivent rien contenir qui ait etO presentd ailleurs pour publication ou dej& paru. En principe, la redaction correspond uniquement avec les auteurs des lettres retenues pour publication. Les lettres refusees sont detruites. Les lettres retenues peuvent etre abreigees ou faire l'objet de modifications d'ordre redactionnel.
An example of an ecologic fallacy I appreciated the excellent review by Dr. C. Laird Birmingham (Can Med Assoc J 1992; 146: 1389-1340) of Report of the Task Force on the Treatment of Obesity.' The task force was convened to address unsafe practices in the weight loss industry. Its recommendations concern therapeutic measures used in relation to our current knowledge of the mechanisms and treatment of
the Canadian Guidelines for Healthy Weights.2 The authors examined various relations between weight and height and concluded that the standard formula for the BMI (the weight in kilograms divided by the square of the height in metres) gave the closest practical approximation to body fat content in the population. The assessment of fatness is not easy. The gold standard is to weigh the person totally immersed in water to measure the relative density, a research technique not readily available in the home or to commercial weight loss clinics. Measurement of skinfold thickness is a simpler measure of fatness and is used routinely in specialized health assessment facilities. However, the technique is subject to significant error when applied by untrained observers. Weight viewed in isolation is meaningless. Weight and height are easily and reliably measured in the community by means of inexpensive equipment that is generally available. It is recognized that the BMI relates weight to height and not to fatness. However, this can be a valid surrogate for fatness in the normal, semisedentary population.' We acknowledge in our report (page 15) that "while the BMI is a suitable screening instrument for many, it is not appropriate for very muscular people." The task force was convened for and its report is directed to "the safety, competence and integrity of [commercial] weight loss
obesity. I wish to support the use of programs" and therefore -to the the body mass index (BMI) as public and those involved in the recommended in the report. We business of weight loss. It is undelayed the production of the re- likely that weight lifters and othport until the Expert Group on ers who have worked to increase Weight Standards had completed their muscularity will enrol volun-
For prescribing information see page 1380
tarily in such programs. The concern that an ecologic fallacy has been promoted is unlikely to detract from the value of the report to those either running or attending commercial weight loss clinics. John A. Hunt, MB, FRCPC Chairman, Working Group Task Force on the Treatment of Obesity
References 1. Report of the Task Force on the Treatment of Obesity, cat no H39-201/ 1991E, Health Services and Promotion Branch, Dept of National Health and Welfare, Ottawa, 1991 2. Expert Group on Weight Standards: Canadian Guidelines for Healthy Weights, cat no H39-134/1989E, Dept of National Health and Welfare, Ottawa, 1988
Diagnostic testing in chronic urticaria and angioedema D
r~. Jerry Dolovich rightfully points out in his letter (Can Med Assoc J 1992; 146: 1528) that textbooks list numerous diseases that can lead to urticaria and angioedema. They also arbitrarily define these conditions as acute or chronic according to whether the episode lasts less than or more than 6 weeks. It is often mentioned that in chronic cases only rarely is an underlying cause found, and therefore most
such cases are considered idiopathic. With this information physicians may become complacent in treating such conditions with pharmacotherapy without bothering to delineate the underlying cause. Most patients first see their CAN MED ASSOC J 1992; 147 (9)
1303
family physician, who usually tries some antihistamine preparations for a few weeks. When symptoms continue to recur a consultation with a dermatologist is sought. By the time the patient gets to see a consultant that magic 6-week period has elapsed, and the patient is labelled as having chronic urticaria or angioedema. Because of the presumption that most cases of chronic urticaria are idiopathic a consultant may try a different set of medications to provide symptomatic relief. I believe that if symptoms reappear after a couple of episodes physicians should make an effort to identify and remove the causal agent(s) instead of continuing to prescribe medication. In this way some patients may escape the situation of being labelled unnecessarily. I agree that extensive investigations such as routine biopsy, culture, serologic testing and radiography are usually not very rewarding. However, in my experience allergy skin tests are extremely rewarding, not useless, as Dolovich proclaims. I was surprised to note that he cannot think of a single case of chronic urticaria or angioedema in which investigation of the cause had been useful. I have observed that in more than half of such cases a cause can be delineated through testing with a wide variety of food and environmental allergens. The difference in our experience may be due to the different battery of allergens that we use when investigating such cases. On the basis of my personal observations I would urge all physicians to put allergy at the top of the differential diagnosis when dealing with urticaria and angioedema. Food and environmental allergens as a cause of these conditions should be ruled out before extensive and expensive investigations are undertaken. We may thus be able to provide dramatic relief to the patient when allergy is 1304
CAN MED ASSOC J 1992; 147 (9)
the cause instead of offering a suscitation, trauma care, toxicology, prehospital care, disaster planlabel and a handful of pills. ning and the administration and Jagat N. Singh, MD management of emergency departWinnipeg, Man. ments. The focus of residency training in family medicine is on comfamily medicine munity-based Is emergency medicine care, with usuand hospital-ward a specialty? ally no more than 2 months' experience in an emergency departEv mergency medicine is a ment in the 2-year training prospecialty, and it has been gram. This is an excellent baseline recognized by numerous for further training in emergency medical jurisdictions throughout medicine; however, in itself it is the Western world. not adequate or appropriate for a The Quebec controversy on physician intending to devote a the status of emergency medicine large part of his or her practice to discussed in "Is emergency medi- emergency medicine. The days of cine a specialty? Quebec MDs dis- learning emergency medicine by agree over controversial issue" trial and error while working (Can Med Assoc J 1992; 146: alone in the emergency depart1632-1633, 1635-1636), by ment in the middle of the night Michel Martin, has nothing to do have surely passed. with the specialty nature of the The results of Quebec's faildiscipline and everything to do ure to recognize emergency mediwith medical politics and "turf' cine as a specialty are predictable. protection by the Federation des Emergency specialists are no difmedecins omnipraticiens du Que- ferent than other specialists and bec. generally choose to practise where Emergency medicine is a pri- they are recognized. The CMA mary-care specialty historically Physician Resource Databank on linked to general medical practice, Dec. 31, 1986, indicated that of and its development as an in- all physicians practising emergendependent discipline has often cy medicine predominantly or exbeen opposed by the existing clusively only 17% in Quebec, as family-medicine establishment. compared with 41% in the rest of The reason for this opposition is Canada, had postgraduate certifiunclear. Emergency medicine and cation in emergency medicine family medicine are both broadly from either the Royal College of based and devoted to the care of Physicians and Surgeons of Canapatients of all ages and with all da or the College of Family Phystypes of health problems. Howev- icians of Canada. This discrepaner, other than in breadth of scope cy exists even though, ironically, the focuses of the two disciplines the oldest and one of the largest differ substantially: training programs in emergency medicine in Canada is located in Emergency medicine is a specialty Quebec, at McGill University. based on knowledge and skills in- the diagnosis and management of the Quebec already has specialists in acute and emergent aspects of illness emergency medicine working in and injury affecting patients of all age its hospital emergency departgroups with diverse medical, surgical, ments. Absurdly, this specialization is only recognized outside of and behavioral disorders.' the specialists' home province. Quebec will recognize emerIn addition, emergency-medicine medicine as a specialty. The gency physicians have developed special is not if but when. issue reexpertise in cardiopulmonary LE lr NOVEMBRE 1992
