Why Is It So Difficult to Influence the Clinical Management of Hypertension?

The capacity to influence the practice of medicine can be seen as being dependent on two forms of communication. First, there are those scientists who have made remarkable discoveries and who have had the ability to communicate them for the betterment of mankind. Examples abound, but just to name a few: Pasteur, Lister, Fleming, and the bevy of 20th-century Nobel Laureates in medicine serve as examples. But these geniuses of science are not my primary concern, which is to focus on the potential for a very different mode of communication to effect change, namely the ability of what may be termed clinical scientists to influence the practice of medicine; these are for the greater part practicing doctors who have devoted much of their lives to clinical research and to communicating their research in the traditional way by publishing articles in peer-reviewed journals, in articles for the lay press, in books, and in the visual and auditory media of radio and television. I was prompted to explore this theme not only to question a fundamental flaw in scientific reasoning, but also to deplore my inadequacy as a clinical scientist who has had ample opportunities to exert a modest influence on the practice of medicine. The assumption in all areas of clinical medicine and among the lay public is that blood pressure (BP) measurement is arrived at as easily as weighing a stone of potatoes, or estimating total cholesterol, when we know, and have known for nearly half a century that, more often than not, the measurement of BP is not only inaccurate but also downright misleading. But all this has been said time and time again by me and by a host of clinical scientists. An editorial from my department back in 1988 stated: “Faced with a patient with borderline hypertension, the doctor should be slow to diagnose hypertension until some attempt has been made to categorise the behaviour of blood pressure over time: ambulatory blood pressure measurement is the best way to do this.”1 So, not alone have we known about the inaccuracy of so-called office BP for half a century, but the serious errors in diagnosis, prognosis, treatment, and demographic assessment have also been evident along with the inevitable wastage of financial resources that must result from reliance on an inaccurate technique.2 To put this into perspective, let us discard for a moment the denotation of hypertension which, after all, is an illness that causes little concern to the average layman. Indeed, dinner conversations may refer flippantly to a “touch of hypertension” or the more fashionable denouement “of course, I have white-coat hypertension.” We do not find such euphemisms of description applied to cancer. So let us assume that medicine devised a measurement that could detect mitotic change in any cellular system in the body, and let us assume further that after decades of use it was shown scientifically that this measurement overdiagnosed cancer in about 20% and underdiagnosed it in 10% of patients. In such a circumstance it would not be unreasonable to expect an outcry from a public outraged that so many people had been overtreated for cancer and so many others had not been correctly diagnosed. Scientists would rightly be indicted for not having discovered the inaccuracy in a measurement technique that had caused so much unnecessary suffering. And, what if a new diagnostic technique would not only identify the patients who had been previously overdiagnosed but would also detect those who had been missed with the previous measurement? There is little doubt but that our healthcare providers would be obliged to make the new measurement available to the population at large. What if the new measurement was more expensive than the previous test and necessitated wearing a monitor for 24 hours? Again, where cancer is concerned, we would all be glad to pay more and put up with a little discomfort in the interest of accurate diagnosis. Moreover, any fiscal considerations would be decided ultimately by the market demand, as the new measurement inevitably became part of the health care armamentarium. This contrived scenario for cancer becomes reality for hypertension, which causes more global morbidity, death, and suffering than all forms of cancer together. The equivalent to the old test for cancer is office BP measurement, which overdiagnoses hypertension in at least 20% of normotensive people (white-coat hypertension) and fails to detect hypertension in at least 10% of the population (masked hypertension).2 But the difference is that there has been no outcry from an indignant public! Not even outrage at the fact that we have had the technique of ambulatory BP measurement (ABPM) for 40 years and have been continuously misclassifying and treating patients over that time. Numerous guidelines and recommendations from international authorities have emphasised time and time again that diagnostic and management decisions for patients with hypertension should be based on ABPM rather than on clinic measurement of BP. Most notable among these have been the recommendations from the National Institute for Health and Care Excellence (NICE) in 2011,3 and just recently from the US Preventive Services Task Force,4 each of which state unequivocally that ABPM should be offered to anyone who has ever had a BP value ≥140/90 mm Hg. Moreover, it has been shown that ABPM is more cost-effective than clinic BP or home BP measurement. Yet, despite all these recommendations, the technique is not routinely available, which brings me back to where I started. How can the enormity of this scientific fiasco be communicated to the public, to the medical profession, and to the healthcare providers? Why, one has to ask, are expensive MRI scans of the brain available to anyone who has had a bang on the head but ABPM is denied patients with elevated BP? Or why, it has been asked, is ABPM not as readily available to patients with hypertension as an ECG is to patients with chest pain? Surely the blame has to be shared. We, the scientists, who know the facts, are ineffective in communicating important lifesaving methodologies and we must learn to do better. The public is badly educated as to the dangers of hypertension and the need to effectively diagnose and manage the condition and again this deficiency must rest with us. Finally, one asks, are editors of medical journals not somewhat culpable in not assisting scientists to communicate their messages more effectively?