Umeå scientist in Lancet: Only one blood pressure value matters for over 50s

Systolic blood pressure (SBP) is the peak pressure in the arteries at the beginning of the heart’s pumping cycle, while diastolic blood pressure (DBP) is the lowest pressure in the rest phase of the cycle. Both are routinely measured in patients, to give a value of systolic over diastolic, e.g. 120/80 mm Hg.

Three world leading hypertension experts — Bryan Williams, University of Leicester; Lars Hjalmar Lindholm, Umeå University, and Peter Sever, Imperial College, London — now say that, because of aging populations, systolic hypertension (SH) is becoming much more common and important due to its high prevalence in patients over 50, compared with diastolic hypertension (DH).

SBP rises with age; but DBP only rises until age 50 years and falls thereafter, at a time when risk of cardiovascular disease begins to rise. Thus there is an increased prevalence of SH over age 50 years and an almost total disappearance of DH:
“Since more than 75% of people with hypertension are aged over 50 years, the burden of disease in mainly due to systolic pressure. The use of diastolic pressure for diagnosis and risk analysis in our ageing populations has thus become illogical.”

To simplify treatment strategies for physicians and policy makers, as well as to better focus the minds of drug innovators on the correct targets, the authors propose that, in patients over 50, only SBP needs to be measured, for four reasons.

Firstly, SBP is more easily and accurately measured than DBP and is a better predictor of risk. Second, communication with patients would be much easier with just one number. Third, doctors themselves have received many conflicting messages about SBP and DBP, and this proposal would simplify things for them. Lastly, focussing a public-health campaign on a single number for people aged over 50 years has the potential to dramatically improve treatment outcomes and reduce the associated disease and death rates.

The risk of cardiovascular disease rises continuously as SBP increases from 115 mm Hg. Most international and national guidelines advocate a target of below 140 mm Hg, but there is a lack of evidence from prospective randomised clinical trials to define the best target for SBP treatment. The authors say:
“Such trials are much needed and perhaps our call for a renewed focus on SBP will provide a catalyst for them to be designed.”

The authors acknowledge that for patients aged under 50 years, the scenario is different. In patients aged under 40 years, up to 40% of patients with hypertension have isolated DH, while between 40 and 50 years this figure is around a third. Thus for these patients, a continued emphasis on both SBP and DBP is appropriate. The authors say:
“However, this much smaller group of patients should not dilute the key message regarding the overwhelming importance of systolic blood pressure for most patients with hypertension.”

The proposal is put forward in a Viewpoint published early Online and in an upcoming edition of The Lancet. All three experts are attending this week’s meeting in Berlin of the International Society of Hypertension (ISH), in which Professor Lindholm is President.

For more information, contact Professor Lars Hjalmar Lindholm, Department of Public Health and Clinical Medicine, mobile: + 46 (0)70 585 35 26,
E-mail: larsh.lindholm@fammed.umu.se

Bryan Williams, Lars H Lindholm, Peter Sever: “Systolic pressure is all that matters”, Lancet, published online, June 17, 2008, DOI:10.1016/S0140-6736(08)60804-1

Editor: Hans Fällman