Correspondence
Borderline Systolic Hypertension
N Engl J Med 1994; 330:1392May 12, 1994
- Article
To the Editor:
The article by Sagie et al. (Dec. 23 issue)1 states that “borderline systolic hypertension and the risk of cardiovascular disease are causally related.” I wonder whether the cart and horse have been reversed with regard to causality.
It is generally accepted that systolic hypertension is the consequence of decreased compliance in the major arteries. The usual cause of this problem is atherosclerosis. Is it not possible, therefore, that the discovery of borderline systolic hypertension merely sorted the study population into two groups: those with atherosclerotic vascular disease and those without it? The contribution of preexisting vascular disease or its consequence, hypertension, to the eventual development of cardiac disease is not at all clear.
My comments are not meant to suggest that treatment may not be worthwhile. I suspect, however, that successful management of hypertension will not convert such patients into those who are fortunate enough to have compliant arteries from the start.
1 ReferencesNorman J. Selverstone, M.D.
Harvard Medical School, Boston, MA 021151
Sagie A ,Larson MG ,Levy D . The natural history of borderline isolated systolic hypertension. N Engl J Med 1993;329:1912-1917
Full Text | Web of Science | Medline
Author/Editor Response
The authors reply:
To the Editor: Dr. Selverstone suggests that atherosclerosis of the major arteries reduces vascular compliance, which in turn produces an elevation of systolic pressure. If so, borderline isolated systolic hypertension (systolic pressure, 140 to 159 mm Hg; diastolic pressure, <90 mm Hg) would be considered a marker of existing atherosclerotic disease rather than a causal contributor to the outcome of cardiovascular disease.
Although this explanation for the association of borderline isolated systolic hypertension with an increased risk of cardiovascular disease is possible, a more plausible explanation comes from a combined reading of epidemiologic studies and trials of hypertension treatment. When combined with epidemiologic data pointing to systolic hypertension as a risk factor for cardiovascular disease, the results of intervention trials offer compelling evidence of a causal relation between systolic hypertension and cardiovascular risk. An earlier study from Framingham1 described the extent of increase in the risk of cardiovascular disease in subjects with definite isolated systolic hypertension (systolic pressure, ≥ 160 mm Hg). Similarly, a follow-up of over 350,000 people who had been screened in the Multiple Risk Factor Intervention Trial2 documented clearly the continuous relation between the level of systolic pressure and the risk of fatal coronary events. As in our report, associations from observational studies do not prove causality, they merely support it. More definitive evidence of causality comes from placebo-controlled, randomized trials of blood-pressure reduction in subjects with systolic hypertension. For example, in the Systolic Hypertension in the Elderly Program, treatment of systolic hypertension resulted in a 32 percent reduction in cardiovascular events3. Similarly, in the Swedish Trial in Old Patients with Hypertension, active blood-pressure treatment was associated with a 40 percent reduction in cardiovascular events4.
4 ReferencesAlex Sagie, M.D.
Martin G. Larson, Sc.D.
Daniel Levy, M.D.
Framingham Heart Study, Framingham, MA 017011
Wilking SVB ,Belanger A ,Kannel WB ,D'Agostino RB ,Steel K . Determinants of isolated systolic hypertension. JAMA 1988;260:3451-3455
CrossRef | Web of Science | Medline2
Stamler J ,Neaton K ,Wentworth D . Blood pressure (systolic and diastolic) and risk of fatal coronary heart disease. Hypertension 1993;13:Suppl I:2-123
SHEP Cooperative Research Group
CrossRef | Web of Science4
Dahlof B ,Lindholm LH ,Hansson L ,Schersten B ,Ekbom T ,Wester P-O . Morbidity and mortality in the Swedish Trial in Old Patients with Hypertension (STOP-Hypertension). Lancet 1991;338:1281-1285
CrossRef | Web of Science | Medline
