Controversies in Hypertension – what are the implications of SPRINT in the context of recent treatment trials?News - Mar. 30, 2017
Special invited plenary - Professor Richard McManus, University of Oxford, United Kingdom
Controversies in Hypertension – what are the implications of SPRINT in the context of recent treatment trials?
Hypertension was discussed with focus on the SPRINT trial and the discussion it has elicited since publication of its results. Prof. Richard McManus first summarised the design and results of this trial, in which 9361 patients aged 50 years or older with SBP between 130 and 180 mmHg, and an increased CVD risk were randomised to either intensive (<120 mmHg) or standard (<140 mmHg) treatment. Medications (less than 4) were up- or downtitrated in both groups to attain the respective targets. Contrary to common practice in most countries, automated clinic BP measurement was performed, consisting of three readings, mostly unattended, of which the average was taken. Measurements were done after the patient rested for five minutes. McManus shared some data of his own that showed a 9 mmHg drop in SBP was seen over three consecutive readings.
The SPRINT trial was terminated early after a median follow-up time of 3.5 years. A reduction of 25% was seen in the primary composite outcome of MI, ACS, stroke, acute HF or CV death, in the intensively treated group as compared with standard treatment. The reduction of the primary outcome in a subanalysis in patients over 75 years old was even larger with an HR of 0.66 for those on intensive versus standard therapy.
McManus reviewed these data in light of other BP-lowering trials, such as the ACCORD trial, in patient with type 2 diabetes. With mean SBPs achieved in groups receiving intensive (119 mmHg) or standard (134 mmHg) treatment similar to the SPRINT trial, no significant difference was seen in a primary composite outcome. The SP3 trial studied targeting 130-149 mmHg or <130 mmHg in patients of at least 30 years old, with recent lacunar stroke. Between those in the higher target group (mean: 138 mmHg) and the lower target group (127 mmHg), no significant difference was seen in the stroke endpoint, nor in all cause death or the other endpoints.
A meta-analysis was performed on RCTs that evaluated different BP targets and included 17 trials, among which SPRINT. Data hinted at a dose-dependent benefit, albeit non-significant, of a lower SBP target when compared to a reference target of <160 mmHg, but when compared to lower reference targets, the RR was even closer to 1, and all comparisons were non-significant.
While discussing the potential benefits of BP-lowering seen in these trials, McManus also pointed out the increased number of adverse events observed with intensive regimes. Modelled projections of applying the SPRINT regimen to the US NHANES population, revealed that not only may this prevent 107500 deaths per year, but it would also be associated with over 55000 episodes of hypotension, and over 34000 of syncope, over 43000 electrolyte disorders, and almost 90000 cases of acute kidney injury.
Thus, the SPRINT data are topic of discussion of various reasons.