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CMAJ
CMAJ - November 2, 1999JAMC - le 2 novembre 1999

Letters · Correspondance

CMAJ 1999;161:941-6

Choosing a first-line antihypertensive

In their systematic review of antihypertensive therapies, James M. Wright and colleagues conclude that "low-dose thiazide therapy can be prescribed as the first-line treatment of hypertension with confidence that the risk of death, coronary artery disease and stroke will be reduced. The same cannot be said for high-dose thiazide therapy, ß-blockers, calcium-channel blockers or ACE [angiotensin-converting-enzyme] inhibitors" [full article]1 Although there may be good reasons for selecting thiazide therapy, such as low cost and low rate of withdrawal for adverse effects, the efficacy data in Table 4 do not support the authors' conclusions that only low-dose thiazide therapy will prevent death and cardiovascular morbidity in patients with hypertension.

Table 4 shows that there was essentially no difference among low-dose thiazide, high-dose thiazide, and calcium-channel blocker therapy with respect to mortality (relative risks 0.89, 0.90 and 0.86 respectively) or total cardiovascular events (relative risks 0.68, 0.72 and 0.71 respectively). For total cardiovascular events, a Mantel­Haenszel analysis2 finds no evidence of heterogeneity between these medications (chi2 = 3.6 on 2 degrees of freedom, p = 0.16). There was lower risk reduction for ß-blockers than for the other medications, but there was no significant difference between the ß-blockers and low-dose thiazide therapy for mortality (relative risk 1.01 and 0.89 respectively). For the ß-blockers, the risk reduction for total cardiovascular events just failed to reach significance at the 5% level (relative risk 0.89, 95% confidence interval 0.78­1.02). There were no trials of ACE inhibitors against placebo, but the one trial comparing ACE inhibitors with calcium-channel blockers (Table 2) suggested that the ACE inhibitor was at least as good as the calcium-channel blockers in reducing mortality and cardiovascular events.

I conclude that the data presented by Wright and colleagues show that low- and high-dose thiazide therapy, calcium-channel blockers and ACE inhibitors are similarly efficacious in reducing mortality and cardiovascular events in patients with hypertension.

Murray M. Finkelstein PhD, MD CM
Mt. Sinai Hospital
Toronto, Ont.

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References
  1. Wright JM, Lee C-H, Chambers GK. Systematic review of antihypertensive therapies: Does the evidence assist in choosing a first-line drug? CMAJ 1999;161(1):25-32.
  2. Rothman KJ, Greenland S. Modern epidemiology. 2nd ed. Baltimore: Lippincott Williams & Wilkins; 1998.

[Contents]

Choosing a first-line antihypertensive
[The authors respond:]

We appreciate Murray Finkelstein's comments about our systematic review; however, we disagree with his conclusion. We carefully chose the wording of our 2 concluding statements. Our first statement, that "low-dose thiazide therapy can be prescribed as the first-line treatment of hypertension with confidence that the risk of death, coronary artery disease and stroke will be reduced," is substantiated by the statistical significance (95% confidence intervals) of the reduction of total mortality, coronary artery disease and stroke with low-dose thiazides, as presented in Table 4. Our second statement was that "the same cannot be said for high-dose thiazide therapy, ß-blockers, calcium-channel blockers or ACE inhibitors." A statistically significant reduction in all 3 measures has not been shown for high-dose thiazides, ß-blockers or calcium-channel blockers (in Table 4 the confidence intervals include 1.00). Nor has it been shown for ACE inhibitors or any other class of drugs, as they have not been studied in trials meeting the criteria of this review.

We therefore cannot prescribe these other classes as first-line agents with confidence that they will reduce each of these 3 adverse outcomes. We did not conclude, as suggested by Finkelstein, that only low-dose thiazides will prevent death and cardiovascular morbidity. Nor did we conclude, as Finkelstein has, anything about the relative effectiveness of low-dose thiazides and the other classes of drugs; the available head-to-head evidence is insufficient to comment on the relative effectiveness of the different classes of antihypertensive drugs.

We did demonstrate in this review that using thiazides as first-line therapy was associated with a greater reduction in systolic blood pressure and a lower rate of withdrawal for adverse drug effects than that associated with some of the other classes of antihypertensive drugs. We did not comment on the cost advantage of thiazides but are pleased that Finkelstein has made this point.

James W. Wright, MD, PhD
Cheng-Han Lee, BSc
G. Keith Chambers, MD
University of British Columbia
Vancouver, BC

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[Contents]

White-coat hypertension

In his recent CMAJ editorial on white-coat hypertension [full article],1 David Spence reviews the question of 24-hour ambulatory monitoring of blood pressure, which often demonstrates a lower blood pressure reading than that done in a medical centre. I agree with this phenomenon.

The patients I refer to a cardiologist for ambulatory monitoring are those whose blood pressure is uncontrolled by combinations of antihypertensive drugs. The cardiologist often measures a normal ambulatory reading, leaving me looking like a fool.

When these patients return to me, do I proceed to ignore the readings over 150/100 mm Hg in my office because their ambulatory numbers were normal? No, I treat on the basis of the higher readings I see in my office. If I am charged with overtreatment, Spence will back me up, as he correctly states that our current success in preventing heart attacks and strokes comes from treating on the basis of office blood pressure readings.

There are now blood pressure testing machines in many drugstores, and many patients also take their own readings at home with equipment we recommend. In virtually every case, the systolic numbers are at least 20 mm Hg lower than what I find at the office.

I advise patients that the office readings, taken in a more stressful situation than most ambulatory settings, demand attention. This may be contrary to current teaching that physicians should base treatment on the lower levels of blood pressure, but life is a compromise. So we may split the difference, shaving a few mm Hg from the top readings. This leaves everybody happy.

David Rapoport, MD
Toronto, Ont.

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Reference
  1. Spence JD. Withholding treatment in white-coat hypertension: wishful thinking. CMAJ 1999;161(3):275-6.

[Contents]

Foreign graduates deserve better

The acute shortage of physicians we face is due not only to government shortsightedness but also to parochialism within the medical profession. For instance, specialists with many years' experience in another province and possessing Royal College certification are not, as a rule, considered fit to practise in Ontario. Are Ontarians more delicate than others or are we more equal than others?

Forty years ago the Malayan Medical Association used excuses such as maintenance of the standard of care to keep people out of practice. My medical degree from Taiwan was a useless piece of paper back in 1959. I was forced to teach high school at a time when the physician­population ratio in my own country was 1 in 10 000. My hometown and its 30 000 people did not have a single practising doctor, yet my wife and I had no opportunity to return to practice because of our foreign qualifications — a plight faced by many foreign medical graduates in Ontario today.

The concern that foreign-trained physicians are inferior is prevalent. To limit foreign medical graduates to a minuscule number of training positions is in itself a form of institutionalized discrimination.

I would like to present a cohort's experience to illustrate a point. Seventy-two students entered the premed class at the National Taiwan University in 1952, and eventually 26 of them completed postgraduate training in North America. One graduate became professor and chief of the Department of Microbiology at Uniformed Services University of Health Sciences in Washington, DC, while another is the chair of cardiovascular surgery at McGill University. Two others became professors at George Washington University in Washington, and another is a professor at the University of Missouri. Only 6 of us ended up doing general practice in North America — everyone else is a board-certified specialist.

If we had arrived in Canada today, we would be consigned to a life of servitude washing bottles and dissecting rats in laboratories. I think the experience of this cohort is proof that foreign medical graduates deserve a fair chance to serve the public.

Ah Yin Eng, MB, DPH
Pembroke, Ont.

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[Contents]

Ticklish distinctions

The CMAJ case report of concurrent babseiosis and Lyme disease in Ontario by Claudia C. dos Santos and Kevin C. Kain [full article]1 contains some incorrect information.

First, the authors state that "205 cases of Lyme disease were reported in this country between 1984 and 1994." In fact, the "205 cases" were in Ontario, not all of Canada.2

Second, they state that Ixodes scapularis and I. pacificus ticks "have been identified in about 250 locations in Canada." The "250 locations" refer to the distribution of the blacklegged tick, I. scapularis, not I. pacificus. In the original reference2, there is no mention of the western blacklegged tick, I. pacificus. This tick has only been documented in British Columbia.

Third, Long Point peninsula is not in Point Pelee National Park. These 2 locations are approximately 200 km apart — a 3-hour car drive.

Finally, the common name of I. scapularis is blacklegged tick, not deer tick.3

John D. Scott, BSc(Agr)
President
Lyme Disease Association of Ontario
Fergus, Ont.

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References
  1. dos Santos CC, Kain KC. Two tick-borne diseases in one: a case report of concurrent babesiosis and Lyme disease in Ontario. CMAJ 1999;160(13):1851-3.
  2. Banerjee SN, Christensen CI, Scott JD. Isolation of Borrelia burgdorferi on mainland Ontario. Can Commun Dis Rep 1995;21:85-6. [MEDLINE]
  3. Keirans JE, Hutcheson HJ, Durden LA, Klompen JSH. Ixodes (Ixodes) scapularis (Acari: Ixodidae): redescription of all active stages, distribution, hosts, geographical variation, and medical and veterinary importance. J Med Entomol 1996;33:297-318. [MEDLINE]

    [Contents]

    Ticklish distinctions
    [The authors respond:]

    We thank John Scott for identifying a typographical error in this report: the sentence that mentions Long Point peninsula should have read "... Long Point peninsula and [not in] Point Pelee National Park."

    We did not claim that there were exactly, or only, 250 locations where either I. scapularis or I. pacificus has been found, nor is this relevant. The point is simply that although ticks capable of transmitting Borrelia burgdorferi or Babesia spp. or both have been found in a number of locations in the country, they are only established in a few.

    Scott is incorrect that blacklegged tick is the only commonly used name for I. scapularis. The term deer tick remains in common use in the medical literature and lay press (in fact, the Centers for Disease Control refer to them as deer ticks in their public information handouts on Lyme disease).

    More importantly, Scott's comments in no way change the conclusion or implications of this case. In fact, since this case was submitted for publication, we have identified and treated 3 more cases of babesiosis in residents of Ontario.

    Claudia C. dos Santos, MD
    Kevin C. Kain, MD
    Toronto Hospital and University of Toronto
    Toronto, Ont.

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    [Contents]

    Controversial cancer care

    I have to hand it to Bill O'Neill, a real entrepreneur (or good samaritan?), for finding a hiatus in the delivery of health care and taking advantage of it [full article].1

    Some time ago, he managed to convince a reporter of the Ottawa Citizen to report extensively on his activities, but that he was able to induce Barbara Sibbald, an editor of CMAJ, to write a 3-page commercial about the so-called Canadian Cancer Research Group is highly disturbing. Interviews with oncologists as quoted by Sibbald would lead the reader to believe that O'Neill's activities are accepted by at least some physicians.

    I express shame and indignation that my own medical journal is willing to sacrifice space to publish such an insult to our beloved profession.

    George Tolnai, MD
    Ottawa, Ont.

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    Reference
    1. Sibbald B. Private company offers hope to cancer patients — for a price. CMAJ 1999;160(11):1619-21.

    [Contents]

    Controversial cancer care
    [The editor-in-chief responds:]

    We believe the report was balanced. Interviews with Robert Buckman, an oncologist, Mike McBurney, a research scientist with the Ottawa Regional Cancer Centre, and Robert Phillips of the National Cancer Institute of Canada provide testimony that counters the claims made by O'Neill. Some of our patients with cancer do visit this and similar clinics. Knowing more about what these clinics are doing — and think they are doing —should help physicians manage the clinical care of their patients with cancer.

    John Hoey, MD

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    [Contents]

    Keeping clinics open

    In their commendable efforts to keep the x-ray clinic in Richmond, Ontario, open [full article],1 Drs. Lucy and Rod Rabb have come up against the hard reality facing most community-based radiologists in the province. The Ontario Health Insurance Plan's facility fees, which are meant to cover the operating costs of a radiology clinic, are insufficient for this purpose unless the clinic is operating at full capacity. As are the Rabbs, many radiologists in Ontario have been subsidizing these costs from their professional fees for years.2 This situation has led to the closure of many small x-ray offices across Ontario and the concentration of operations in larger referral centres where economies of scale can be found.

    Ian Hammond, MD
    Department of Radiology
    Ottawa Hospital
    Ottawa, Ont.

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    References
    1. Sibbald B. Rural docs provide rent-free space to keep lab open. CMAJ 1999;161(5):477.
    2. Deloitte & Touche Management Consultants. Ontario Association of Radiologists survey of practice economics. 1995.

    [Contents]

    Drug information handouts

    A recent CMAJ editor's preface [full article]1 discussed drug reactions and interactions and outlined the need for information to be given to the patient. You specifically commented on the importance of the information given to patients by their pharmacist.

    Throughout the years I have been grateful to pharmacists who keep my patients (and me) out of trouble by double-checking drug doses and instructing the patient about important drug interactions. However, in recent years there has been an increasing tendency for drugstores to hand out printed sheets that cover every possible side effect of a drug. This scares many patients and frequently leads to noncompliance, anxiety and confusion.

    As a dermatologist, I have found the information on these printed sheets to be a problem for patients suffering from acute or recent-onset dermatitis. I have instructed the patients to use the strong steroid frequently and consistently, but the instruction sheet has warned them of side effects and told them to use it sparingly. This advice is incorrect, because in some cases it is necessary to use potent doses to achieve a therapeutic effect. Side effects can develop from long-term use of topical steroids but they are not, practically speaking, a problem over the short term when the drugs are used under close supervision. My prescription pads now state the following at the bottom: "No instruction sheets for topicals or Kenalog please." I prefer to fully inform patients in the office about the medication they are prescribed.

    Information about drugs is important to patients but I believe that the printed drug handout sheets lack perspective and are presently doing more harm to patients than good.

    Robert N. Richards, MD
    Toronto, Ont.

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    Reference
    1. Drug interactions: Who warns the patient? [editor's preface]. CMAJ 1999;161(2):117.

    [Contents]

    Toying with titles

    Your article "Vinyl toys, medical devices get clean bill of health" notes that the American Council of Science and Health (ACSH) offers reassurance about the safety of phthalates in these items [full article].1 The article identifies the leader of this panel as Dr. Everett Koop, former US surgeon general and by implication an independent authority. However, what is not revealed in your report is that the ACSH may be heavily freighted with conflicted interest. One source claims that the ACSH receives 76% of its funding from industrial contributors, including Exxon, the largest manufacturer of phthalates in the world, and that "most of the ACSH panel have ties to the chemical industry."2

    The Pugwash Foundation, which addresses health and environmental issues related to scientific advances, claims that the scientific community has to a certain extent lost the trust of the public.3 The title and content of your article illustrate one of the reasons. A firm conclusion on a controversial scientific question is headlined and supported by an apparently credible source without mention of competing interests. A policy of stating such interests is applied elsewhere in CMAJ but apparently not in the News and analysis section.

    Alban C. Goddard-Hill, MD
    Belleville, Ont.

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    References
    1. Vinyl toys, medical devices get clean bill of health. CMAJ 1999;161(4):361,363.
    2. Montague P. Precaution and PVC in medicine, Part 2. Rachel's Environ Health Weekly 1999;(662).
    3. Atiyah M. Science for evil: the scientist's dilemma. BMJ 1999;319:448-9. [MEDLINE]

    [Contents]

    Toying with titles

    As a Canadian-born and trained physician, I was both amused and disappointed by the irony in the same-page publication of 2 news articles in CMAJ. In "Media coverage of health stories often inaccurate, MDs report" [full article],1 Greg Basky nicely reviews a Canadian Science Writers Association survey in which only 34% of physicians believed that accurate media coverage occurs for medical health information. Forty-one percent felt that poor reporting was "primarily due to the media's desire to grab audience or reader attention."

    The irony comes when this sentence is seen in juxtaposition with the headline of the subsequent anonymous report. "Vinyl toys, medical devices get clean bill of health" [full article]2 cites the findings of "an independent, non-profit group of US researchers" formed by the ACSH, an organization apparently self-described as "helping Americans distinguish between real and hypothetical health risks." Your reporter acknowledges that this panel's report "directly contradicts another study from an international consortium of 180 organizations, including the American Nurses Association."

    The headline clearly gives CMAJ readers the impression that these chemicals are safe, in spite of grave doubt about the matter. Not stated is that the ACSH is a source of considerable controversy itself, being heavily funded by the chemical industry. One might reasonably question if any panel of experts chosen would likely reflect the views of the body that formed it.

    In the spirit of accuracy in medical reporting, I would suggest that a more appropriate title to this article would be "Debate continues over safety of vinyl toys, medical devices."

    Gerald H. Ross, MD
    Past President
    American Academy of Environmental Medicine
    Salt Lake City, Utah

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    References
    1. Basky G. Media coverage of health stories often inaccurate, MDs report. CMAJ 1999;161(4):361.
    2. Vinyl toys, medical devices get clean bill of health. CMAJ 1999;161(4):361,363.

    [Contents]

    Toying with titles
    [The associate editor, news and features, responds:]

    Alban Goddard-Hill's points are well taken. He is quite correct in surmising that the News and analysis section does not list competing interests. This section and the Features section contain medical news items written by journalists. If we are aware of conflicts of interests that may call into question the credibility of a source we certainly report them. Likewise, we make every attempt to provide balanced coverage. In the article in question, we also quote from Health Care Without Harm, an organization of 41 groups including Greenpeace and the American Public Health Association, which refutes the claims of the ACSH.

    Gerald Ross' comments about the headline are similarly well taken. We attempt to write objective yet enticing titles; sometimes we fail.

    Barbara Sibbald, BJ

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    [Contents]

    Are alternative funding plans a good idea? [Correction]

    In the response by Sam Shortt and Marshall Godwin1 to a letter to the editor by Michael Jacka and Brian Milne, the first sentence of the third paragraph should have read, "Second, 71% of the referring physicians stated that they had not increased referrals to consultants not participating in the alternative funding plan in Kingston or to consultants in other secondary care centres." We apologize for this error.

    The online version is correct.

    Reference

    1. Shortt S, Godwin M. Are alternative funding plans a good idea? [letter]. CMAJ 1999;161(5):485-6.