Chicago - The continuing decline in mortality rates associated with cardiovascular disease in this country still cannot be fully explained, but University of Minnesota researchers assert that lower blood pressure trends may provide important clues.
Aaron R. Folsom, MD, and colleagues read the blood pressures of adults in 1980 and found a significant decrease compared to BP rates of a similar group tested in 1973. In a recent issue of the Journal of the American Medical Association, the researchers say that the lower pressures may explain the recent reduction of cardiovascular disease rates seen in the studied community.
"Improvements in the control of moderate and severe hypertension have probably contributed to the recent decline in coronary heart disease mortality in the United States," the researchers say. "It is likely that the improved hypertension detection and control demonstrated herein have contributed to this favorable trend."
But in an accompanying editorial, Harvard Medical School researcher Oglesby Paul , MD, warns against making generalizations based on the study's results.
"The overall detection and control of hypertension are still far from ideal , and one must consider that the experience of the Minneapolis-St. Paul area is not necessarily or probably representative of many other parts of the country," says Paul.
The Minnesota researchers surveyed blood pressures of 1,656 adults in 1980-1981, and compared results with a similar survey of 3,475 adults conducted in 1973-1974. In the earlier period, only 40% of hypertensive persons had adequately controlled blood pressures; 13% were treated but had uncontrolled conditions; 20.4% had known hypertension but were untreated; and 25.5% had previously undetected hypertension.
By contrast, the 1980-1981 group had 76.1% hypertensive persons with adequately controlled blood pressures; 8.5% treated but uncontrolled; 8.8% known but untreated hypertension; and 6.6% previously undetected hypertension.
"Improvements in the control of moderate and severe hypertension have probably contributed to the recent decline in CHD mortality in the United States, " the researchers conclude.
Paul's cautionary note adds, "Before physicians congratulate themselves or the way in which they have prolonged and saved many lives by prescribing diuretics, B-blockers, reserpine, hydralizaine, and other agents, they must recall that the decline in mortality in the United States from hypertensive and cerebrovascular diseases has been documented at least since 1940, beginning well before the current approach to hypertension."