| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
TRACK to:
|
|
Electronic letters published:
![[Read Comment]](/icons/misc/sectionDOWN.gif){kind=icon}
Prehypertension
Re: Prehypertension---yet another pseudodisease
Prehypertension and Cardiovascular Mortality
Prehypertension---yet another pseudodisease
|
|
|||
|
William E. Feeman Jr., M.D., Bowling Green, OH Family physician Wood County Hospital
Send response to journal:
|
I would like to comment on the article by Liszka, etal, (1) and the accompanying editorial by Green (2) concerning prehypertension and its effect on morbidity and mortality. My comments are based on my own study of my patients over the 4 November 1974-4 November 2003 time frame. (3-5) My study is called The Bowling Green Study (BGS) of the Primary and Secondary Prevention of Atherothombotic Disease (ATD). Over the 29-year time frame, 1009 patients developed some form of ATD, such as acute myocardial infarction, acute brain infarction, abdominal aortic aneurysm, etc. Blood pressures are available for all 1009 patients. 539 patients are males; 470 patients are females. Examining the systolic blood pressure data, one finds that 48% of males and 47% of females had hypertension based on systolic blood pressure (SBP)> 140 HG. 39% of males and 35.7% of females had pre-hypertension (SBP: 120-138 mostly). 13% of males and 19% of females had normal blood pressure (SBP<118). Of course, other risk factor data is available for these patients. Cigarette-smoking data is present in virtually all of these patients. Lipid data is present in 71% of these patients. Taken together, cigarette smoking, dyslipidemia, and hypertension are the main risk factors for ATD. (5) The lipid risk factor that I use is the cholesterol retention fraction (CRF, or [LDL-HDL]/LDL). (3-5) The CRF exceeds the ability of LDL-cholesterol by itself to predict ATD. (6) The CRF is abnormal at levels > 0.70, of at any level if LDL-cholesterol >170 mg/dl. This latter scenario holds because HDL-cholesterol is unable to compensate for unlimited LDL-cholesterol and this effect begins when LDL-cholesterol > 170 mg/dl. (3-5) The cholesterol threshold (CThr) is exceeded if CRF> 0.70 and/or LDL>170 mg/dl. Cigarette smoking is the chief risk factor for ATD. (7) Cigarette smoking can cause ATD events in the absence of CThr abnormalities. Hypertension has similar properties but mainly affects older ATD patients. In ATD, diabetes tracks with SBP. (8) Turning to the subject of prehypertension, in my practice, only 5% of male ATD patients and 21% of female ATD patients with prehypertension could not have been predicted by CThr and/or cigarette smoking status. Those males who were not predicted by CThr and/or cigarette smoking status, yet had prehypertension, had an average of ATD onset of 80 years, whereas their female counterparts had an average age of ATD onset of 74 years. In the author's opinion, this difference is due to passive smoking. In the BGS, it is rarely is ever found that a never-smoking male is married to a current-smoking female. On the other hand, it is common for a never-smoking female to be married to a current-smoking male. Hence, a male who is classed as a never-smoker is rarely exposed to cigarette smoke, whereas the same cannot be said for females. Passive smoking is a known risk factor for ATD. (8) Diabetes in the absence of the major three risk factors, may also be operative here. This is not to imply that SBP had no role in ATD. The role of SBP, however, is subservient to that of CThr or cigarette-smoking status. Indeed, ATD in younger patients is characterized by more marked abnormalities of CThr and/or cigarette-smoking whereas ATD in older patients is characterized by milder abnormalities of CThr, a past history of cigarette smoking, and diabetic hypertension. (8). In other words, the concept of prehypertension is at best unnecessary in the prediction of ATD. At worst, the concept of prehypertension diverts attention away from the major causes of early-onset ATD: CThr abnormalities and cigarette-smoking. Sincerely, William E. Feeman Jr. M.D. References: 1. Liska, Heather. Prehypertension and Cardiovascular Morbidity. Annals of Family Medicine. Vol. 3;No.4. July/August 2005. 294-299. 2. Green, Lee. Prehypertension, Patient Outcomes, and the Knowledge Base of Family Medicine. Annals of Family Medicine. Vol. 3; No. 4. July/August 2005. 292-293. 3. Feeman, W.E. Jr. The Bowling Green Study of the Primary and Seconday Prevention of Atheroschlerosis: Descriptive Analysis, Findings, Applications, and Conclusions. Ohio J. Sci. 92(5):153-181. 4. Feeman W.E. Jr. The Bowling Green Study of the Primary and Secondary Prevention of Atherochlerotic Disease: Update 1991-1993. Ohio J. Sci. 94(4): 105-112. 5. Feeman W.E. Jr. Prediction of the Population at Risk of Atherothrombotic Disease. Experimental and Clinical Cardiology. Winter 2004. 9:(4); 235-241l 6. Data presented at the 2002 Annual Scientific Assembly of the American Academy of Family Physicians in San Diego. 7. Feeman W.E. Jr. The Role of Cigarette Smoking in Atherothromboic Disease: An Epidemiologic Analysis. J. Cardio Risk. 1999; 6:333- 335. 8. Data presented at the Annual Heart Association Second International Conference on Heart Attacks and Strokes in Women in Orlando. Competing interests: None declared |
|||
|
|
|||
|
John G. Scott, New Brunswick, USA Assistant Professor of Family Medicine UMDNJ-Robert Wood Johnson Medical School
Send response to journal:
|
Bravo to Maryann Napoli! While I admire the technical statistical expertise in the paper by Lizka, et al., I am troubled by their interpretation of the data, and the larger implications of further medicalizing well people. We already know that lack of exercise, poor eating habits and psychosocial stress decrease the quality (and perhaps quantity) of life, both in the present and in the future. We don’t need a new disease, prehypertension, with which to bludgeon our patients into changing their life styles. Even though JNC-7 does not recommend drug treatment for prehypertension, I agree with Ms. Napoli that this paper will be used by the pharmaceutical companies as a rationale for expanding the indications for antihypertensive medications. I can hear the pharmaceutical rep’s spiel now: “Doctor, you know how difficult it is to get people to change their life styles. For those who won’t or can’t, our product will bring that blood pressure to normal and cut their risk of heart attack or stroke in half.” By looking at the life table figure in the paper, it appears to me that the unadjusted absolute increased risk of having a cardiovascular event for people with prehypertension is about 5% at 17 years. It would have been helpful for the readers if the authors had explicitly reported that risk rather than forcing us to guesstimate from the figure. Because of the statistical techniques used to adjust for confounders, it is not possible to convert the 1.32 hazard ratio into an adjusted absolute risk increase, but it is clear that the adjusted number would be smaller than 5%. While hazard ratios allow the calculation of confidence intervals and are useful to researchers, the relevant information to clinicians and patients (as so cogently pointed out by Ms. Napoli) is the absolute risk increase (or reduction). Reporting of only relative risks overemphasizes both the degree of risk and the value of treatment. Finally, I note from the paper that by defining prehypertension as an illness, 80% of the population is sick. Something is wrong with this picture. Competing interests: None declared |
|||
|
|
|||
|
William B Kannel, Framingham, MA, UA Physician, epidemiologist, Framingham Heart Study, Ramachandran S, Vasan, MD
Send response to journal:
|
The report of Liska and colleagues examines the outlook for the new JNC-7 promulgated prehypertension risk category. Prior Framingham reports investigating the former normal and high normal blood pressure categories (JNC-6) provided the impetus for the recommended change in hypertensive blood pressure characterization (1,2). This report confirms the Framingham finding of an excess risk in prehypertension in a larger and more generalizable population sample. The finding of an incremental blood pressure risk within the prehypertensive category reflects the continuous graded influence of blood pressure with absence of critical values (3).The interesting finding in this report is the observation that 80-90% of the prehypertensive population sample had at least 1 cardiovascular risk factor. An adiposity-related tendency for other risk factors to cluster with elevated blood pressure has been well documented (4). It is likely that the CVD risk in this prehypertensve blood pressure range increases with the number of associated risk factors present. CVD risk ratios in the prehypertensive range while significantly increased, are still on average quite low. This observation suggests that persons in this category need a global cardiovascular risk assessment using the Framingham Study scoring system to select those who should be targeted for lifestyle measures of diet, weight control, and physical exercise (5). For some individuals with multiple risk factors indicating a high multivariable vascular risk, even antihypertensive monotherapy along with control of the other risk factors may be considered. Only with global vascular risk assessment is it possible to avoid needlessly alarming or falsely reassuring these prehypertensive patients and subjecting them to therapy they do not need. William B. Kannel M.D., Ramachandran S. Vasan, M.D. Framingham Heart Study, Boston University School of Medicine, Framingham, MA References 1. Vasan RS, Larson MG, Leip EP, et al. Assessment of frequency of progression to hypertension in non-hypertensive subjectsin the Framingham Heart Study. Lancet 2001; 358:1682-1686. 2. Vasan R, Larson MG, Impact of high normal blood pressure on the risk of cardiovascular disease. NEJM 2001; 345:1291-1297. 3. Kannel WB, Vasan R, Levy D, Is the relation of blood pressure to risk of cardiovascular disease continuous and graded or are there critical values? Hypertension 2003; 42:453-456. 4. Wilson PWF, Kannel WB. Clustering of risk factors, obesity and syndrome X. Nutr Clin Care 1999; 1:44-50. 5. Wilson PWF, D’Agostino RB, Levy D, Belanger AM, Silbershatz H, Kannel WB. Prediction of coronary heart disease using risk factor categories. Circulation 1998; 97:1837-1847. Competing interests: None declared |
|||
|
|
|||
|
Maryann Napoli, New York City, USA Center for Medical Consumers
Send response to journal:
|
Every dozen or so years, the threshold is lowered for high blood pressure, thereby labeling more and more Americans as hypertensive. In 2003, the JNC-7 went one step further with new classification called prehypertension. Overnight, 50 million Americans became candidates for drug therapy. Heather A. Liszka and colleagues have identified an increased risk for heart disease in the upper reaches of prehypertension, and multiple risk factor reductions are advised. But we already know that lifestyle changes are not effective. Multiple lifestyle changes together can make significant reductions in blood pressure, but studies have failed to demonstrate that this will reduce the rate of heart attack and stroke.1 And it’s well established that multiple risk factor reductions have no effect on mortality. 2 Here’s how I see this study play out. Many insured people labeled prehypertensive will eventually go on lifelong drug therapy. They will not be informed about side effects (e.g., sexual dysfunction) or that drug trials last only five years, at best. Nor will they be warned about the potential adverse interactions with multiple non-hypertensive drugs—a likely scenario for most elderly people. If I were diagnosed as prehypertensive—and in the unlikely event that I would consider taking drugs for it—I would want to know what my ten-year risk is in absolute terms--both with and without drug therapy. Instead Liszka and colleagues express the increased cardiovascular risk as 1.32. That’s not going to mean much to the average intelligent layperson, or perhaps most doctors. Furthermore, this study comes at a time when some researchers are questioning the excessive focus on blood pressure measurement. They argue that a person’s entire risk profile should be taken into account before drug treatment is proposed. 3 Whenever a committee of experts expands the boundaries for who has a disease or condition, I always look for the pharmaceutical industry’s influence. It’s not hard to find. Strong financial ties to drug companies were found in nine of the 11 committee members who created prehypertension.4 Think of all the diagnostic thresholds that have been lowered in recent years. Cholesterol, osteopenia, diabetes 2…just to name a few. Pretty soon there won’t be a healthy adult left in the entire country. At very least we’ll all be pre-disease. -- 1 Alderman M. Looking toward JNC-8: The future of hypertension treatment guidelines: a panel discussion at the New York Academy of Sciences, May 11, 2005. 2 Ebrahim S, Davey Smith G. Multiple risk factor interventions for primary prevention of coronary heart disease. The Cochrane Database of Systematic Reviews 1999, Issue 2. 3 MacMahon S, Neal B, Rodgers A. Hypertension—time to move on. Lancet. 2005 March 19-25. 4Wilson, Duff, The hidden big business behind your doctor’s diagnosis. The Seattle Times, June 26, 2005 www.seattletimes.com see Special Reports: Suddenly sick. Competing interests: None declared |
|||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
TRACK: