After a fall her husband contacted the family doctor and me, and instructions were given to bring her to the emergency department. By the time she arrived she was in deep coma, with no response to pain. Her serum glucose level was 2.2 mmol/L. The medication bottle was with her, so that the error was quickly identified. A diagnosis was made of metabolic coma secondary to hypoglycemia, and she was admitted to the intensive care unit for treatment. Miraculously, she recovered without residual organic mental deficits. The College of Physicians and Surgeons was contacted, and it advised that a report be submitted to the College of Pharmacy for appropriate action. Chlorpropamide instead of chlorpromazine has the potential for acute and fatal consequences. This is not the only serious error that has happened to one of my patients and those of immediate colleagues. However, there is no formal mechanism for reporting these incidents (as there is for adverse drug reactions) in order to compile figures and gain an overall picture of how often such mistakes are occurring. Each is dealt with on an individual basis. Knowing whether chlorpropamide and chlorpromazine have been incorrectly interchanged more frequently than the two times reported may support the case for changing similar drug names and, as Dr. Landis suggested, for helping "develop learning tools that would make physicians and pharmacists more aware of this potentially serious problem." In the meantime, we can continue to encourage patients to be informed about their medications, and we should be receptive to reassessing prescriptions thoroughly when questions are raised.

Similar drug names worry OMA, American pharmacists A Ithough I wholeheartedly agree with the Newsbrief item in CMAJ (1990; 143: 401) Canadian pharmacists are equally concerned about medications that look and sound alike. The most recent example that comes to mind is Lasix v. Losec. Moreover, there are groups of pharmacists in community and hospital practice who do monitor and report problems to the Drugs Directorate of the Department of National Health and Welfare, the Pharmaceutical Manufacturers Association of Canada and the pharmaceutical licensing bodies in each province. There may be some merit in looking at this as an issue affecting all health care professionals nationally. A joint review of drug names by a multidisciplinary committee would combine a numer of perspectives and be very useful. One has only to think of the long line of cephalosporins to realize that physicians, nurses and pharmacists must be equally concerned about this problem. The confusion over similar drug names does not seem to be the responsibility of any one country or group of people. However, it is important to inform those responsible for naming compounds that there is a great deal of risk to patients if drug names look or sound alike. Gery R. King, BSP President Canadian Society of Hospital Pharmacists Toronto, Ont.

Cognitive impairment in the elderly

Jean E. Porter, MD, FRCPC

Coordinator Psychiatric Consultation-Liaison Service Mississauga Hospital Mississauga, Ont. 196

CAN MED ASSOC J 1991; 145 (3)

I t was interesting to note the very high levels of cognitive vimpairment quoted in "Cog-

nitive and behavioural impairment among elderly people in institutions providing different levels of care," by Drs. Louise Teitelbaum, M. Lynne Ginsburg and Robert W. Hopkins (Can Med AssocJ 1991; 144: 169-173). Using the Mini-Mental State Examination they found a score of less than 24 (indicative of moderate or severe cognitive impairment) in 84% of residents of a nursing home, 84% of those in a home for the aged and 96% of patients in a psychiatric hospital. Although it is not surprising that the number of impaired patients in psychogeriatric wards was so great the figures from the nursing home and especially from the home for the aged are much higher than Nancy Moulton and I have found in our work in rural areas of Newfoundland (unpublished data), and we wonder whether Teitelbaum and associates' figures are representative of the situation across Canada. Using the Canadian Mental Status Questionnaire developed by Robertson, Rockwood and Stolee' we found the prevalence of moderate or severe cognitive impairment among residents (mostly psychogeriatric patients) of a longstay hospital ward to be 77%, among people in a nursing home to be 50% and among those living at home to be 9%. We tested people aged 70 years and older. The total prevalence of moderate or severe dysfunction in the population was 1 1%, a rate not significantly different from Jeans and colleagues' estimate from surveys done in several parts of Canada.2 Problems with comparing surveys of cognitive function have been the widely different methods used and the different populations studied; moreover, estimated prevalence rates are affected by the cutoff points and diagnostic criteria of the various tests for dementia.3 Had we moved the cutoff point between mild and moderate cognitive impairment For prescribing information see page 232 -

down by just 1 point (on a scale of 10) in our study, the prevalence of severe or moderate impairment would have dropped to 67% in the hospital ward and to 44% in the nursing home. Conversely, if the cutoff point had been moved up by a point the prevalence in the hospital ward would have risen to 92% (close to that found by Teitelbaum and associates) and in the nursing home to 61%. With the projected doubling of our elderly population by the year 20214 most of those who are cognitively impaired will be resident in the community and will have to be cared for there. Canada has one of the highest rates of elderly people living in institutions,5 but even here almost half of people with moderate or severe cognitive impairment live at home, as do the vast majority of those with mild impairment.6,7 In our study, of people with severe or moderate cognitive impairment only 31% lived in institutions and 69% lived at home. Although the latter figure may be higher than in urban areas because of more extended kinship networks and a relative lack of available institutions it is clear that with the onset of "the silent epidemic" of dementia in Canada8 most of the caring will have to be done by families and family doctors. We cannot afford not to evaluate our community services for such people.9

4.

5. 6.

7. 8. 9.

prevalence rates. Psychol Med 1985; 15: about the fact that Canadian com771-788 munity services for demented paPopulation Projections for Canada and tients will be increasingly in dethe Provinces (cat no 91-514), Statistics mand and increasingly strained. Canada, Ottawa, 1974 Fact Book on Aging, Dept of National Therefore, the time for assessment Health and Welfare, Ottawa, 1983: 68- of our provision of such services 69 O'Connor DW, Pollitt PA, Hyde JB et is now upon us. al: The prevalence of dementia as measured by the Cambridge Mental Disor- Louise Teitelbaum, MD, FRCPC ders of the Elderly. Acta Psychiatr Hotel Dieu Hospital M. Lynne Ginsburg, MB, ChB, FRCPC Scand 1989; 79: 190-198 Preston GAN: Dementia in elderly Robert W. Hopkins, PhD adults: prevalence and institutionaliza- Kingston Psychiatric Hospital Kingston, Ont. tion. J Gerontol 1986; 41: 261-287 Beck JC: Dementia in the elderly: the silent epidemic. Ann Intern Med 1982; Reference 97: 231-241 Worrall G, Chambers LC: Can we af- 1. Folstein MF, Folstein SE, McHugh PR: ford not to evaluate services for persons Mini-Mental State: a practical method with dementia? Can Fam Physician for grading the cognitive state of pa1989; 35: 573-580 tients for the clinician. J Psychiatr Res 1975; 12: 189-198

[The authors respond.:

First, a score of less than 24 on the Mini-Mental State Examination indicates some degree of cognitive impairment' rather than moderate or severe cognitive impairment, as suggested by Dr. Worrall. Second, although the criteria for admission to the psychogeriatric wards in a provincial psychiatric hospital were not specifically indicated in our article (patients must be elderly and suffering from an organic mental disorder) the patients in them would likely be substantially different from the "residents (mostly psychogeriatric patients) of a longstay hospital ward." Third, since cutoff scores are (or should be) experimentally deGraham Worrall, MSc, CCFP rived points in a statistical distriDistrict medical officer bution their artificial movement Glovertown Medical Clinic Glovertown, Nfld. is not appropriate. If, however, minor score differences have the effect of greatly changing the References number of cases falling above or 1. Robertson D, Rockwood H, Stolee P: A below the cutoff score one should short mental status questionnaire. Can examine the validity of the instruJAging 1982; 1: 16-20 2. Jeans ER, Helmes E, Merskey H et al: ment. In our study such changes Some calculations on the prevalence of as plus or minus one point would dementia in Canada. Can J Psychiatry have had only minimal effects on 1987; 32: 81-88 the distributions (about 1% or 3. Kay DWK, Henderson AS, Scott R et

HIV infection among Quebec women giving birth to live infants I n the final paragraph of her reply (Can Med Assoc J 1991;

144: 955) to my letter (ibid: 954-955) Dr. Catherine A. Hankins states: "The only cases of HIV [human immunodeficiency virus] transmission through breast-feeding that have been documented worldwide have occurred in infants whose mothers were infected not during pregnancy or at birth, but, rather, post partum, in most cases through contaminated blood transfusions."

Hankins appears to be unaware of work by Blanche and associates and the HIV Infection in Newborns French Collaborative Study Group.' In a prospective study of infants born to women seropositive for HIV type 1, 32 of 117 infants (27%) were seropositive after 18 months; "5 of the 6 infants who were breast-fed became seropositive, as compared with 25 of 99 who were not (p < 0.01)." 2%). It would seem that this findal: Dementia and depression among the Finally, we wholeheartedly ing is also at variance with Hankelderly living in the Hobart community: the effect of diagnostic criteria on the agree with Worrall's comments ins' next statement: "It has not

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CAN MED ASSOC J 1991; 145 (3)

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lI' AO(JT 1991