The Systolic Blood Pressure Intervention Trial (SPRINT), sponsored by the National Heart, Lung and Blood Institute in the USA, allocated 9361 hypertensive patients (mean age 68 years) to two systolic blood pressure treatment targets (either < 120mmHg or < 140mmHg). Although SPRINT intended to enrol hypertensive patients at high cardiovascular risk, it specifically excluded patients with diabetes mellitus or prior stroke. SPRINT was stopped earlier than planned, after a mean follow-up of 3.26 years, on the recommendation of its data and safety monitoring board, and data were published on 9 November 2015. A mean systolic blood pressure reduction to 121.4 mmHg in the intense-treatment group, compared with a mean systolic blood pressure reduction to 136.2 mmHg, was reported to significantly decreasethe primary outcome (the composite of myocardial infarction, acute coronary syndrome, stroke, heart failure or death from cardiovascular disease) by 25% and all-cause mortality by 27%. Although the SPRINT trial provided important information, a number of criticisms has been raised regarding some results of the study. For example the patients included in SPRINT, although all had to have ‘increased’ cardiovascular risk, cannot be considered at a particularly high level of risk. Indeed, the group with standard treatment had an overall incidence of major cardiovascular events (inclusive of myocardial infarction, acute coronary syndrome, stroke, heart failure and cardiovascular death) just above 2% per year. In particular, incidence of death from cardiovascular disease was rather low (0.43% per year) and only about a quarter of all-cause death, against an expectation of about 50%. A further element of criticisms came from the evidence that the cause-specific event most importantly reduced by intense treatment in SPRINT appears to be heart failure (38 heart failure events prevented of a total of 76 cardiovascular events prevented; a marked reduction in sudden cardiac death, known to be particularly prevalent in heart failure patients). Heart failure is certainly a clinically relevant outcome, but at clear difference from myocardial infarction and stroke, not to say mortality, heart failure in trials is not defined by really ‘hard’ measures, but on the basis of symptoms diagnosed by hospital physicians the patients are referred to. Furthermore, of all cardiovascular outcomes, heart failure is the one that is not only influenced by blood pressure-lowering per se but also by the class of blood pressure-lowering drugs being used.
With this critical background in mind this presentation will examine whether and to what extent the SPRINT trial results can be of help in the treatment of the diabetic hypertensive patients, well known to be characterized by a very high cardiovascular risk as well as by the need of obtaining an effective blood pressure control by antihypertensive treatment. This because international guidelines on hypertension recommend maintaining blood pressure below 140 mmHg systolic and 90 mmHg diastolic in the general hypertensive population up to the age of 80 years. A more aggressive blood pressure target is recommended when the hypertensive patient has an additional risk for cardiovascular disease, such as if the patient has diabetes, renal disease, or a prior history of cardiovascular disease. In these situations, guidelines encourage decreasing blood pressure below 130/80 mmHg to grant additional cardiovascular protection. The possibility that the SPRINT trial results might be applied in diabetic hypertensive patients will be critically examined by reviewing three sets of relevant studies: randomized trials, post-hoc analysis of prospective studies, and studies on organ damage.
University Milano-Bicocca, C/O San Gerardo Hospital, Italy