Article Text
Statistics from Altmetric.com
Commentary on: OpenUrlCrossRefPubMed.
Context
There is uncertainty regarding optimal blood pressure (BP) targets in treating hypertension. Most recent guidelines have recommended a systolic target of <140 mm Hg. The Systolic Blood Pressure Intervention Trial (SPRINT) compared cardiovascular (CV) outcomes in non-diabetic hypertensive patients randomised to standard (systolic blood pressure (SBP) <140 mm Hg) or intensive treatment (<120 mm Hg).1 Composite CV events and total mortality were significantly reduced with intensive treatment. A prespecified analysis evaluated older patients (≥75) and has now been published.
Methods
SPRINT compared outcomes with treatment targets of <120 mm Hg and <140 mm Hg in hypertensive patients at medium/high CV risk identified by previous CV events (except stroke), high Framingham risk scores or age ≥75.1 Patients with diabetes or recent heart failure were excluded. Patients were randomised to one of the BP targets, but thereafter treatment was open label, with drugs selected at investigator discretion to achieve the appropriate goals. BP was measured by an automated device: after a 5 min rest, three readings at 1 min intervals were averaged to provide the official measurement; readings were unobserved by medical staff. The primary study end point was a composite of CV events and included non-fatal myocardial infarction, acute coronary syndrome not resulting in a myocardial infarction, non-fatal stroke, non-fatal acute decompensated heart failure and death from CV causes. Only patients aged ≥75 were included in this new analysis.
Findings
The mean age of patients was 80; 62% were men. The median follow-up was 38 months. SBPs were 123.4 mm Hg in the intensive group (n=1317) and 134.8 mm Hg in the standard group (n=1319). On average, the intensive group received one more antihypertensive drug than the standard group. Event rates for the primary CV outcome were 2.59%/year in the intensive group and 3.85%/year in the standard group: HR 0.66 (95% CI 0.51 to 0.85). The key secondary outcome of total mortality also favoured intensive treatment: 0.67 (0.49 to 0.91). A prespecified frailty index divided patients into ‘fit’, ‘less fit’ and ‘frail’ categories. Intensive treatment was similarly beneficial for CV events and mortality across all three frailty subgroups. Adverse events trended higher in the intensive group than the standard group: for hypotension, 2.4% vs 1.4%; and for acute kidney injury or renal failure, 5.5% vs 4.0%.
Commentary
This analysis demonstrates compelling CV and mortality benefits of intensive BP control in patients aged ≥75. The measurement method in SPRINT provided BP values about 7–10 mm Hg lower than conventional readings, so the SPRINT intensive and standard systolic values of 123 and 134 mm Hg approximate to 130 and 142 mm Hg in clinical practice. This is important because aiming for <120 mm Hg in older patients in clinical practice has not been tested and could pose risks. Indeed, there were trends towards symptomatic hypotension and reduced renal function with intensive treatment.
The landmark Hypertension in the Very Elderly Trial (HYVET) studied patients aged ≥80 (mean: 84).2 Compared with placebo, active therapy in HYVET (144 mm Hg) significantly reduced mortality and CV events. SPRINT now reports that a further BP reduction to 130 mm Hg in older people produces additional benefits. In SPRINT, progression of frailty was associated with increased events, but intensive therapy protected against events and death regardless of frailty status. Frailty should no longer justify withholding treatment.
One question arising from SPRINT is whether the benefits of intensive therapy were due to lower BP or to non-haemodynamic protective effects of the additional drugs in these patients. Empirically, however, the outcome benefits of up-titrating drug therapy to achieve an intensive BP target are now clearly established. In early 2014, JNC8 recommended that the systolic goal in patients aged ≥60 be relaxed to <150 mm Hg.3 This new SPRINT analysis refutes that recommendation. Even so, guideline writers should not overextrapolate from SPRINT. For instance, patients at lower CV risk than SPRINT4 or with diabetes5 could be in danger of increased events with excessive BP reduction.
Implication for practice
A conventionally measured SBP target of 130 mm Hg provides strong CV and mortality protection in medium/high risk hypertensive adults aged ≥75, including those classified as ‘frail’. Hypotensive and renal adverse events can occur, but are outweighed by the benefits of treatment.
Footnotes
Competing interests None declared.
Provenance and peer review Commissioned; internally peer reviewed.