Geriatricians’ perspective on findings from the STEP and the SPRINT trials with a special focus on their similarities and differences

The Trial of Intensive Blood Pressure Control in Older Patients with Hypertension (STEP trial) is a very recent major trial which sought to determine whether lower systolic blood pressure (SBP) targets are beneficial for older adults with arterial hypertension. The Systolic Blood Pressure Intervention Trial (SPRINT) was another ‘big impact’ trial that sought evidence regarding benefits and risks of strict blood pressure (BP) targets on cardiovascular outcomes. There are several similarities and differences between these two trials. The STEP trial allocated patients aged 60– 80 either to the intensive (SBP target: 110–130mmHg) or to the standard treatment (SBP target: 130–150mmHg) group. In a median follow-up of 3.3 years, intensive approach yielded a 26% relative risk reduction in primary cardiovascular composite outcome. Noteworthy, safety outcomes were not different among groups besides hypotension in the intensive arm. The SPRINT trial, which compared the benefit of SBP target <120mmHg with treatment to a target <140mm Hg in a same median follow-up period, demonstrated the same risk reduction, i.e. 25% lower risk of primary cardiovascular composite outcome with intensive approach. Unlike the STEP trial, the SPRINT, however, reported an increased risk of serious adverse events with intensive treatment; i.e. syncope, electrolyte disturbances and acute kidney injury in addition to hypotension. Both the STEP and the SPRINT should be interpreted with caution because most of the frail older adults (i.e. people having dementia, previous stroke, advanced stage renal disease) were excluded. In the STEP trial, the participants had a relatively young mean age (66.2 years) and low prevalence of co-morbidities (diabetes, 19%; cardiovascular disease, 6.3%; chronic kidney disease, 2.5%). Mean diastolic blood pressure (DBP) was 83mmHg. Body-mass index (BMI) was 26 kg/m2 suggesting that malnutrition was not a major issue neither was frailty. The SPRINT trial, similarly, comprised young-older adults (mean age, 68 years) and mostly individuals with overweight and a baseline DBP of 78mmHg, all suggesting low frailty prevalence. Considering the baseline characteristics of both trials, lower BP targets seem beneficial for healthy, fit older adults. Of note, physical frailty should not be overlooked while determining such strict thresholds and in order to avoid treatment-related harm, more flexible treatment targets should continue to be adopted in frail older people. SPRINT trial has an important plus value because, a further analysis for those aged 75 years or older has been conducted in which physical frailty was taken into account via gait speed and frailty index (FI). These analyses showed that, there was no significant benefit favouring the intensive approach in frail people, except a favourable result was obtained for FI when primary composite outcome and all-cause mortality were considered together (P¼0.02). Yet, FI is criticized as being more like a disease checklist, and a reliable frailty assessment can rather be made by adopting a phenotypic-not cumulative-model of frailty. As such, the results of the SPRINT should not be interpreted as an advantage of an intensive treatment of arterial hypertension compared to standard treatment in frail people. Another major difference that needs consideration is the BP measurement protocol. Namely, the SPRINT used automated office BP (AOBP) measurements, eliminated white-coat effect, and ended up with lower BP measurements than usually expected. This was important since SBP readings are consistently lower (approximately 5–15mmHg) with AOBP compared to conventional methods. Hence, it can be interpreted that the targets showing benefits in the SPRINT were equivalent to_126–136mmHg for conventional methods (where BP is measured by staff); that fits very well to the targets recommended by several current guidelines for older adults. Although both trials used validated ‘‘oscillometric’’ devices (Omron Healthcare, Model 907 in the SPRINT and Omron HBP-1100U in the STEP), allowed an at least five minutes resting before BPmeasurement and took an average of three measurements taken one minute apart, only the STEP trial performed office BP measurements not automatically but by a trained staff member in a research-protocol. This way of measurement is expected to give higher BP values than AOBP, which is reported as high as 7mmHg for SBP. It is remarkable that SBP obtained in the STEP trial (126.7mmHg SBP measured by staff-guided research office measurement protocol that is equivalent to 119.7mmHg SBP if AOBP technique would be used) was _2mmHg (1.8mmHg) lower than the SBP obtained in the SPRINT trial (a SBP 121.5mm Hg measured by AOBP). Hence, the results of the STEP trial suggest a beneficial effect of even lower SBP target in fit older adults. This finding is noteworthy and pointed out for the first time in this paper and should be taken into account. Indeed, the aim of the SPRINT investigators, i.e. providing an SBP <120mmHg in the intensive-arm, has been accomplished by the STEP group.