Hypertension Guidelines disagree on the definition of the more appropriate blood pressure (BP) target to achieve. A shared feature of Guidelines was the definition of precise (albeit differing across Guidelines) BP targets in different patient categories (Table).
Does the evidence support the definition of precise BP targets overall and in different patient categories?
Evidence from observational studies. A direct relation between BP and risk of cardiovascular disease emerged from observational studies including a large meta-analysis (Lancet 2002). Most studies showed that after correction for several confounders (cancer; heart failure etc) the lowest cardiovascular risk occurred at low values of achieved BP (<120/80 or even < 100/60 mmHg).
Evidence from intervention studies. Meta-analyses of randomized studies between different drugs or BP targets showed two main findings:
(a) The larger the BP difference between randomized groups in the achieved BP the greater the benefit (particularly on stroke and heart failure) in the group with the lower achieved BP.
(b) When comparing a more intensive with a less intensive BP target (i.e. 120 vs 140 mmHg) the risk of major cardiovascular disease was lower with the more intensive strategy. In a meta-analysis a more intensive strategy reduced stroke by 20%; myocardial infarction by 15%; heart failure by 25%; cardiovascular death by 18% and all-cause death by 11% (Hypertension 2016) when compared to a less intensive strategy. BP targets considerably differed across the studies.
Evidence regarding tolerability of treatment. Some Guidelines suggest that a more intensive BP target could be achieved at condition that the treatment is well tolerated. However the concept of good treatment tolerability holds at any level of achieved BP (not only below 140/90 mmHg) irrespective of the BP target. There is no evidence supporting safety thresholds not to be exceeded when the treatment is well tolerated.
The lowest well tolerated BP is a reasonable and evidence-based BP target irrespective of the cardiovascular risk status of the patient.
Table: BP targets according to major hypertension Guidelines.