SPRINT Trial Type Blood Pressure Measurements in Patients After Kidney Transplantation
Condition: Arterial Hypertension; Kidney Transplant; Complications
MeSH terms: Hypertension
Study type: Observational

Summary: 
      The SPRINT study used a blood pressure measurement procedure that differs from earlier
      studies in arterial hypertension. SPRINT type readings are lower than regular office
      measurements. The extent of the disagreement between SPRINT and office measurements may
      differ in distinct patient groups. This difference is not yet known for patients after renal
      transplantation. However, it is important to know the difference in order to apply SPRINT
      findings to transplant recipients.
    

Detailed description: 
      Most clinical trials on the treatment of arterial hypertension use office blood pressure
      measurements (Franklin et al. 2001; Hansson et al. 1998) both as inclusion criteria and study
      end-points. In these trials, blood pressure is taken by manual or automated devices in
      outpatients coming to a study center, as recommended by the European Society of
      Cardiology/European Society of Hypertension (ESC/ESH) Guidelines for the management of
      arterial hypertension (Mancia et al. 2013). The target blood pressure as recommended by
      European (Mancia et al. 2013) or US (James et al. 2014) guidelines largely depends on the
      results of the Hypertension Optimal Treatment (HOT) study (Hansson et al. 1998). This large
      trial with >18.000 participants measured blood pressure with an oscillometric device three
      times in a row in seated patients after 5min of rest. This and similar trials form the
      backbone of our knowledge about what is considered normal blood pressure and what blood
      pressure levels should be aimed at when using antihypertensive treatment (Zanchetti et al.
      2009).

      Studies using 24h-blood pressure measurement devices indicated that the normal values are
      lower (average 10/5mmHg) with this technique than with regular office measurements (Head et
      al. 2010). It is well known that there is a so called "white coat" hypertension, i.e. higher
      blood pressure values are taken in the doctor's office than at home (Mancia et al. 1987). The
      amount of this white-coat effect is largely different between individuals. Although
      white-coat hypertension itself has some prognostic impact on the patient (Verdecchia et al.
      2005) it is much less relevant than overt hypertension. It seems reasonable to keep the White
      coat effect in mind to avoid over-therapy in patients in whom this effect is particularly
      strong.

      While the framework for clinical decision making is mostly based on studies using office
      blood pressure readings, the SPRINT study (Wright et al. 2015) recently used another way of
      measuring blood pressure. The SPRINT study included more than 9.300 cardiovascular high-risk
      individuals without diabetes mellitus. It was a randomized prospective trial with
      intervention aiming at a low (<120 mmHg) vs. standard (<140 mmHg) systolic blood pressure.
      The trial was stopped early because of the large benefit of the intervention on the combined
      cardiovascular end-point. Since publication of this study, there is a vivid scientific
      discussion whether the low blood pressure goal should be aimed at in different patient
      populations.

      The SPRINT study used a unique way of determining blood pressure. Patients were left alone in
      a quiet room with a programmed blood-pressure reading device that took readings at intervals
      after 5 minutes of relaxing. Recent studies showed that the blood pressure readings taken
      with the SPRINT technique are relevantly lower than the readings with regular office blood
      pressure measurements (Wohlfahrt et al. 2016).

      Patients after renal transplantation very frequently have arterial hypertension (Kasiske et
      al. 2004; Paoletti et al. 2009). This is in part induced by the kidney disease or effects of
      the transplant and the immunosuppressive therapy; thus it might be considered a form of
      secondary hypertension. The KDIGO guideline (KDIGO clinical practice guideline for the care
      of kidney transplant recipients 2009) recommends to maintain blood pressure <130/80 mmHg in
      these patients. This recommendation is based on analogy to data from the general population
      and has not been formally proven in transplant patients. In order to determine if the SPRINT
      results can be extrapolated to transplant recipients as well, it is important to show the
      effect size of the different blood pressure measurement techniques (SPRINT vs. regular office
      BP) in this particular patient group.

      The study intends to quantify the difference in blood pressure when read by regular ("real
      life") measurement or by the SPRINT procedure (primary goal).

      In addition the study will describe factors that influence this difference (e.g. renal
      function, proteinuria, age, time since transplantation...) (secondary goals).
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        -  Patients (m/f) with a functional renal transplant who are not dependent on dialysis
             treatment

          -  Age 18 - 99 years

          -  Riva-Rocchi blood pressure measurement at least at one arm possible

          -  Informed consent