New hypertension guidance risks overdiagnosis and overtreatment

The UK’s National Institute for Health and Care Excellence (NICE) has launched an updated draft guideline for the diagnosis and management of hypertension in adults.1 The main changes are to recommend drug treatment of stage 1 hypertension for people with a 10% risk of cardiovascular diseases over 10 years—down from a previous threshold of 20%—and to consider treating younger adults with a risk below 10%. NICE presents limited evidence for these recommendations, concluding that “evidence suggested some benefit of treating people with stage 1 hypertension” but “most uncertainty was in treating stage 1 hypertension, particularly for people with a lower cardiovascular risk.”1

Lowering the threshold for treating hypertension has implications beyond changes to disease definitions, including risks to our wellbeing and shifts in our conceptualisation of health and disease. The new draft NICE guidance has at least three serious problems.

Firstly, the guidance does not benefit from a recently published checklist of eight essential items that must be considered before modifying a disease definition.2 This checklist has been used to scrutinise the 2017 American College of Cardiology/American Heart Association (ACC/AHA) hypertension guideline,3 concluding that most new “patients” created by the expanded criteria will not benefit from the label “hypertensive.” One item in the checklist (differences between new and previous definitions) is assessed adequately in the NICE guidance; one is assessed inadequately (reasons for modification); and the remaining six items are not assessed at all (box 1).

The only harms mentioned in the new draft guidance are hypotension and “harms, such as injury from falls and acute kidney injury.”1 However, five decades of studies have reported the harms associated with being labelled hypertensive.45 These include increased absenteeism from work, lower self rated health, and psychological and marital harm from, for example, anxiety and depression.345 In addition, the SPRINT trial, to which the guidance refers, found that 1 in 50 patients experienced serious adverse drug effects during 3.3 years of intense treatment.3 These included hypotension, syncope, electrolyte derangements, acute kidney injury, and acute renal failure.

Secondly, the guidance gives insufficient attention to patients’ preferences and values, one of the three fundamental principles of evidence based medicine.6 NICE highlights “the importance of discussing the person’s preferences and encouraging lifestyle changes before starting treatment”1; but how should this be done in the face of so much uncertainty (box 1), including limited evidence? Furthermore, robust evidence shows that lifestyle interventions offered after a health check (plus pharmacological primary prevention for some) have no effect on cardiovascular mortality or morbidity even among people with identified risk factors or hypertension.7

Thirdly, the guidance is not explicit about why a 10% risk of cardiovascular disease over 10 years should be classified as a disease. This is a fundamental question. The ontological status of hypertension is primarily as a risk factor4: the higher the blood pressure, the greater the risk of cardiovascular disease, and the better the chance of benefit from drug treatment.8 Blood pressure is a continuum with no clear boundary between normal (health risk small enough to be accepted) and pathological (health risk unacceptably high). To avoid overmedicalising healthy people, recommendations must be evidence based and follow a detailed consideration of the consequences of any changes for individuals, populations, and health systems. This has not been done for NICE’s proposed changes, but use of the 2017 ACC/AHA guidance labels 46% of all US adults9 and 63% of those aged 45 to 7510 as having hypertension.