A key trigger for the decision to lower the diagnostic threshold appears to be the results of the US-based SPRINT trial. This found benefits to reducing blood pressure to a systolic reading of 120mmHg, rather than 140mmHg, for those at high risk of heart disease or stroke.
Even before the new guidelines were released there were concerns that SPRINT would promote a “one size fits all” approach to lowering blood pressure. Other trials, including those done in lower-risk populations, failed to find the same benefits as SPRINT. This underscores the importance of individualising decisions about lowering blood pressure, taking into account both the patient’s overall risk profile and their preferences.
Why is this harmful?
Our analysis found 9% of newly diagnosed hypertensives who are at high risk of a heart event or stroke, or who already have a history of heart disease, might benefit from the tighter guidelines. But the vast majority, which is the 80% of newly diagnosed who are at low risk of a heart event or stroke, will not benefit and may be harmed by the new diagnostic criteria. For the 11% of newly diagnosed who have an intermediate risk of heart disease, the benefits and harms are often in rough balance.
Changing the diagnostic and treatment thresholds for hypertension could put people at risk in three ways:
First, wider disease definitions mean more people are labelled as unwell, even if they have a low risk of a disease. Labelling a person as having hypertension increases their risk of anxiety and depression, as compared to the risk for people with the same blood pressure who aren’t labelled as hypertensive.